Ionizable Lipids for Liver Delivery

CQ-12 (CQ12) is a chloroquine-derived, autophagy-inhibitory lipidoid containing a 7-chloroquinoline headgroup and a hydroxyl-bearing C12 lipid chain. It was selected from the CQ6–CQ18 series for incorporation into autolysosomal degradation-inhibitory lipid nanoparticles (AUDI-LNPs). Replacing 30% of the SM-102 molar fraction with CQ-12 produced a five-component formulation containing 15 mol% CQ-12 and increased luciferase expression approximately 5.3-fold in HEK293T cells under the reported conditions. The study also evaluated CQ-12-substituted MC3 and ALC-0315 formulations, subcutaneous and intravenous mRNA delivery, and local intratracheal delivery. IL-10 and TGF-β mRNA formulations were investigated in mouse models of psoriasis and acute lung injury, respectively. CQ-12 supports research into autophagy-modulating LNPs and cytokine mRNA delivery.

A18B8C14 is an α-branched amine ionizable lipid developed using the photochemistry-based ionizable lipid library (PILL) platform. Its structure contains two secondary amines linked by a pentamethylene spacer and two ester-containing branched hydrophobic arms. A18B8C14 was identified as a lead for mRNA delivery; the publication reports higher in vivo expression with its optimized LNP formulation than with an MC3-based benchmark. The supporting information documents intravenous reporter-mRNA delivery, formulation screening, cellular uptake and endosomal colocalization, particle stability, and dose-dependent blood chemistry. It is intended for research on mRNA-LNP formulation and delivery.

U-502 is a Janus dendritic ionizable lipid with two tertiary amines, two hydroxyl groups and six C8 alkyl tails attached through ether-containing dendrons and ester linkers. In a 16-lipid study, U-502 and U-503 were the leading intravenous mRNA-expression candidates, with modestly higher luciferase signals than ALC-0315 in BALB/c mice at 0.5 mg/kg mRNA and a 3-hour readout. The U-502 formulation had a reported size of 108 nm, PDI of 0.125, apparent LNP pKa of 6.36 and mRNA encapsulation efficiency of 91.83%. U-502 also underwent cell transfection, lysosomal colocalization and representative tissue-histology studies. It supports preclinical research into liver-dominant systemic mRNA delivery and headgroup–tail structure–activity relationships.

U-503 is a Janus dendritic ionizable lipid with two tertiary amines, two hydroxyl groups, two ester linkers and six C10 alkyl tails connected to dendritic cores through ether bonds. It was identified alongside the C8-tail analogue U-502 as a leading intravenous mRNA-expression candidate in a 16-lipid study. In BALB/c mice given 0.5 mg/kg luciferase mRNA, U-503 produced a modestly higher 3-hour expression signal than the ALC-0315 comparator under the reported formulation conditions. Its LNP formulation had a size of 114 nm, PDI of 0.122, apparent LNP pKa of 6.31 and encapsulation efficiency of 89.36%. U-503 is a preclinical research candidate for systemic mRNA delivery and matched tail-length comparisons with U-502.

U-510 is a three-tail Janus dendritic ionizable lipid containing an N-methyl tertiary amine, a hydroxypropyl head segment, an ester linker and three C8 ether-linked hydrophobic tails. In an intravenous luciferase-mRNA study in BALB/c mice, it showed a spleen-biased organ-expression profile within the U-509–U-512 series. The authors reported 52% spleen-targeting efficiency in the context of liver and spleen luminescence at 3 hours after 0.5 mg/kg mRNA; this is not a percentage of transfected spleen cells or injected dose. The U-510 LNP formulation had a reported size of 113 nm, PDI of 0.146, apparent LNP pKa of 6.38 and encapsulation efficiency of 87.88%. It supports preclinical evaluation of splenic mRNA expression rather than maximum whole-animal expression.

iL-19 is an aminoethoxy-functionalized ionizable lipid with a triamine scaffold, two ester linkages and four doubly branched hydrophobic tails. It was identified as the overall lead for circular RNA delivery in a 2026 JACS study. With circRNA encoding firefly luciferase, iL-19 LNPs produced approximately 28-fold higher expression than the SM-102 benchmark in C2C12 cells and approximately 2.5-fold higher expression after intramuscular administration in BALB/c mice under the reported conditions. The reported circRNA formulation uses iL-19, DSPC, cholesterol and DMG-PEG2000 at 50:10:38.5:1.5 mol%. It supports preclinical investigation of circular RNA delivery to muscle; comprehensive safety and immunogenicity evaluation remains outstanding.

PA97MD101 is an ester-containing ionizable lipid with a tetraethylenepentamine-derived headgroup and two branched hydrophobic ester arms. Identified through machine-learning-guided screening and independent animal validation, its LNPs produced approximately fourfold higher hepatic luciferase expression than SM-102 in mice after intravenous Fluc mRNA delivery at 0.1 mg/kg. The study also demonstrated Cre-dependent liver recombination and Cas9/sgTtr-mediated TTR suppression. Formulation-dependent activity was associated with acidic-pH membrane activity and reduced lysosomal colocalization. PA97MD101 is a preclinical research candidate for hepatic mRNA and CRISPR cargo delivery.

LC-1 (LC-lipid-1) is an ionizable lipid identified by screening a 384-member Ugi-reaction library with a large, 5.7-kb ABE–NanoLuc mRNA cargo. The cited study evaluated LC-1 lipid nanoparticles for delivery of Cas9 and base-editing cargos to the liver, brain and lung in mice, using different formulations and administration routes.

6Ac1-C12 is an ionizable cationic lipid with a hexaester degradable core and six C12 hydrophobic alkyl tails, featuring a pKa around 6.0 and strong endosomal escape capacity. Its four-component LNPs deliver mRNA mainly to liver endothelial cells after IV injection and remain stable for 30 days at 4°C. Formulated without cholesterol, its three-component system enables lung-targeted delivery with low in vivo toxicity, and the ester core facilitates biodegradation for versatile mRNA applications.

11-10-8 is a degradable, branched ionizable lipidoid identified in a combinatorial screen for mRNA delivery. In the cited mouse study, its optimized LNP formulation supported liver-directed reporter mRNA expression, TTR gene editing with Cas9 mRNA and sgRNA, and FGF21 mRNA expression in a diet-induced obesity model.

D-Lin-MC3-DMA(MC3) is the most potent cationic lipid that has been synthesized for Lipid nanoparticles (LNPs) to deliver the siRNA.

DLin-DMA is an ionizable amino lipid with cationic properties and a pKa of 6.7. It is widely utilized in lipid nanoparticle (LNP) formulations alongside helper lipids to enable efficient nucleic acid delivery.

DLin-KC2-DMA is a highly potent ionizable lipid used in the formulation of lipid nanoparticles (LNPs) for the delivery of siRNA. It represents a significant advancement over earlier generations of lipids, such as DLin-DMA, due to its dramatically improved gene silencing efficiency.

LP-01 is an ionizable cationic amino lipid (pKa = ~6.1). It has been used in the generation of lipid nanoparticles (LNPs). LNPs containing LP-01 and encapsulating both Cas9 mRNA and modified single-guide RNA (sgRNA) for the transport protein transthyretin (Ttr) induce gene editing in liver cells in mice in a dose-dependent manner resulting in reduced serum Ttr levels for at least 12 months.

DODMA, also known as MBN 305A is a a cationic lipid containing the unsaturated long-chain (18:1) oleic acid inserted at both the sn-1 and sn-2 positions. It has been used in the composition of lipospomes formulated as stable nucleic acid lipid particles that can encapsulate siRNA or other small molecules to be used for drug delivery

DODAP, also known as 1,2-Dioleoyl-3-dimethylammonium-propane, is a cationic lipid. It has been used as a component in liposomes that can be used to encapsulate siRNA, immunostimulatory oligodeoxynucleotides, antisense oligonucleotides, or chemotherapeutic agents for in vitro and in vivo delivery.

ALC-0315 is an ionisable aminolipid that used for mRNA compaction and aids mRNA cellular delivery. ALC-0315 can be used to form lipid nanoparticle (LNP) delivery vehicles.

CKK-E12 is a ionizable lipid in combination with other lipids make up the lipid nanoparticles which are used to deliver RNA-based therapeutics. cKK-E12 was highly selective toward liver parenchymal cell in vivo.Multitail lipids usually have three or more tails and tend to form more cone-shaped structures due to the increase of tail crosssection, which enhances the endosome escape and mRNA delivery efficiency.CKK-E12 is an ionizable lipid with four lipid tails and diketopiperazine core-based head. It has shown excellent efficiency in delivering CRISPR-Cas9 mRNA and sgRNA.cKK-E12 iLNPs encapsulated mRNA was used to investigate the effect of Toll-like receptor 4 (TLR4) on iLNPsmediated mRNA delivery, and it has been demonstrated that the targeting, safety and efficacy of iLNPs are closely related to disease state. In other words, even though iLNP delivers therapeutic mRNA to a given cell type in one disease state, it is not guaranteed to deliver mRNA to the same cell type in another disease. As same as MC3 and C12-200, CKK-E12 is also used to be a positive control ionizable lipid when exploiting new ionizable lipids.

503O13 is a degradable, four-tail ionizable lipidoid from a second-generation siRNA-delivery library. In the cited mouse Factor VII study, the non-optimized 500-series formulation was screened at 5 mg/kg and optimization of the 503O13 formulation reduced its reported EC50 to 0.01 mg/kg. The exact optimized helper-lipid molar ratio was not disclosed. Results below apply to the cited LNP, not to the neat lipid or a commercial batch.

5A2-SC8 is a dendrimer for miRNA delivery to late-stage liver tumors with low hepatotoxicity. 5A2-SC8 shows potent EC50 < 0.02 mg/kg (siRNA against FVII (siFVII)) in dose-response experiments, and well tolerated in separate toxicity studies in chronically ill mice bearing MYC-driven tumors. 5A2-SC8 is a degradable lipid-like compound (ester-based dendrimer) for small RNAs delivery.5A2-SC8, was obtained by screening a large library of more than 1500 ester-based dendrimers containing ionizable amino groups, which have three tertiary amine heads and five lipid tails. Based on this library, the in vitro transfection efficiency of different formulations of 5A2-SC8 iLNPs was evaluated, discovering the optimal formulation (5A2-SC8, DOPE, cholesterol, PEG at a molar ratio of 15:15:30:3) of 5A2-SC8 iLNPs for delivering fumarylacetoacetate hydrolase (FAH) mRNA to liver.After the intravenous injection via tail, the model mice of hepatorenal tyrosinemia type I had strong FAH protein expression, which prevented body weight loss and increased the survival rate of hepatorenal tyrosinemia mice . In addition to introducing utility of 5A2-SC8 iLNPs for the therapeutic intervention, the 5A2-SC8 iLNPs containing DOTAP have been used to establish complex mouse models via intravenous injection, including in situ liverspecific cancer model and in situ lung-specific cancer model. Based on this iLNPs delivery system, 5A2-SC8 induced model construction method overcomes the time-consuming and costly disadvantages of traditional animal models establishing methods, including transgenesis and gene engineering in embryonic stem cells.

FTT5 is a lipid-like compound for efficient delivery of long mRNAs in vivo.

246C10 is a synthesized ionizable lipid. 246C10 can be formulated into lipid nanoparticles (LNPs) with dioleoylphosphatidylethanolamine (DOPE), cholesterol, and C16-PEG2000 ceramide (PEG-lipid) as well as mRNA. The lipid nanoparticle formulations can be used for mRNA delivery. To obtain iLNPs that could specifically target liver sinusoidal endothelial cells (LSECs), six different ionizable lipids (241C10 to 246C10) were synthesized by an epoxide ring-opening reaction with piperazine- or piperidine-containing amines. Biodistribution and gene regulation of various iLNPs were assessed in vivo, and the results showed that the 246C10 iLNPs (containing piperazine amine) had the highest luciferase expression in the liver. When further analyzing the 246C10 iLNPs transfection efficiency in different types of liver cells, it was found that tdTomato fluorescence was mainly concentrated in hepatocytes, not in LSECs. Figure 6f shows that 80% of hepatocytes are fluorescent, 40% of LSECs are fluorescent, and 20% of Kupffer cells are fluorescent. Due to the mannose receptor on LSECs, mannose-PEG lipid was introduced into 246C10 iLNPs to alter the distribution of iLNPs in different liver cells. As shown in Figure 6g, tdTomato fluorescence distribution was 15% of hepatocytes, 70% of LSECs, and 15% of Kupffer cells, significantly improved the ability of iLNPs to actively target LSECs. In contrast, this work indirectly shows that the iLNPs with piperazine head lipid are more able to deliver mRNA to the liver and translate the target protein than the iLNPs with piperidine head lipid. It is worth mentioning that the preparation buffer of 246C10 iLNPs could influence the encapsulation efficiency of mRNA. With the addition of sodium chloride in the citrate buffer, the encapsulation efficiency of CRISPR-Cas9 mRNA and sgRNA was increased. These iLNPs were able to treat hemophilia safely, without causing hepatotoxicity, the immune response induced by Cas9 and off-target editing.

SM-102 is an ionizable amino lipid that has been used in combination with other lipids in the formation of lipid nanoparticles.Administration of luciferase mRNA in SM-102-containing lipid nanoparticles induces hepatic luciferase expression in mice. Formulations containing SM-102 have been used in the development of lipid nanoparticles for delivery of mRNA-based vaccines.

L319 (LIPID 319) is a novel ionizable, biodegradable lipid for delivery of short interfering RNAs (siRNAs). L319-LPN displays rapid elimination with pKa of 6.38 and also shows well tolerated up to 10 mg/kg.

ATX-126(ATX-0126, 10p) is an ionizable cationic lipid (pKa = 6.38).It has been used in the generation of lipid nanoparticles (LNPs) for the delivery of siRNA. Intravenous administration of LNPs containing ATX-126(ATX-0126, 10p) and encapsulating Factor VII siRNA decrease Factor VII blood levels in mice.

C12-200 is a well-known cationic lipid used in the formulation of lipid nanoparticles (LNPs) for the delivery of therapeutic nucleic acids, including siRNA, mRNA, and CRISPR components. It is widely recognized for its high in vivo potency at low doses and is often used as a positive control ionizable lipid in research exploring new ionizable lipids.

ssPalmO-Phe(SS-OP) is a self-degradable material for the delivery of oligonucleotides. ssPalmO-Phe is a self-degradable derivative of ssPalm that is self-degraded in the intraparticle space by a specific hydrolytic reaction. ssPalmO-Phe is beneficial for overcoming the plasma/endosomal membrane, LNP-ssPalmO-Phe can be used to deliver both nucleic acids.

Genevant CL1 (lipid 10) is a novel ionizable lipid for rna delivery.Lipid 10 rapidly accumulated in the liver within the first hour of dosing (reflecting LNP uptake), but levels then steadily declined over the ensuing 2 weeks period, similar to MC3.Lipid 10 afforded more than double the expression of either approved lipid. We also observed high splenic expression for ALC-0315, which correlated with higher MCP-1 levels.Animals received a single 5 µg IM dose of LNP encapsulating firefly luciferase (fLuc) mRNA. Whole body imaging was performed 6 h later and expression at the injection site quantified. Lipid 10, ALC-0315, and SM-102 showed similar expression at the injection site, all greater than the older generation benchmarks lipids (DLinDMA, KC2, MC3). Lipid 10 and ALC-0315 also showed high expression in the liver, while SM-102 was less, and more similar to MC3.Lipid 10-based LNP reported similar anti-HA IgG titers to MC3 and ALC-0315 (Comirnaty) LNP, and higher than the SM-102 (SpikeVax) LNP composition. MCP-1 levels were generally similar, although the ALC-0315 composition had a significantly higher response at the 5 µg dose. All formulations reported good stability when stored frozen at −80 °C or at 2–8 °C for 1 month.

Lipid 2,2(8,8) 4C CH3 is an ionizable cationic lipid (pKa = 6.69).1 It has been used in the generation of lipid nanoparticles (LNPs) for the delivery of siRNA in vivo. LNPs containing lipid 2,2(8,8) 4C CH3 and encapsulating siRNA targeting Factor VII decrease plasma Factor VII protein levels by 90% in mice.

CL4F8-6 is an ionizable cationic lipid (pKa = 6.14) that has been used in combination with other lipids in the formation of lipid nanoparticles (LNPs).1 LNPs containing CL4F8-6 and encapsulating an mRNA reporter accumulate specifically in the mouse liver after intravenous administration. LNPs containing CL4F8-6 and encapsulating mRNA encoding the Cas9 nuclease (mCas9) and single-guide RNA (sgRNA) targeting Ttr (sgTtr), the gene encoding transthyretin, have been used to induce CRISPR-mediated gene knockdown in mice resulting in a reduction of serum levels of TTR.

4A3-SCC-10 is a disulfide bond-containing biodegradable ionizable cationic lipid (pKa = 6.22) that has been used in the generation of lipid nanoparticles (LNPs) for the delivery of mRNA in vitro and in vivo. LNPs containing 4A3-SCC-10 and encapsulating a Cy5-RNA reporter have improved endosomal escape ability over Cy5-RNA-encapsulated LNPs containing 4A3-SC-10, which does not contain disulfide bonds, in HeLa cells. Intravenous administration of LNPs containing 4A3-SCC-10 and encapsulating an mRNA luciferase reporter selectively accumulate in mouse liver.

4A3-SCC-PH is a groundbreaking linker-degradable ionizable lipid (LDIL) that features a glutathione (GSH)-responsive cone-shaped molecular structure. This unique architecture enables superior endosomal escape and rapid mRNA release, making it highly effective for mRNA delivery. In vivo studies have highlighted its exceptional performance, showing a 176-fold increase in mRNA delivery efficiency to the liver compared to DLin-MC3-DMA, a widely used benchmark lipid. Both 4A3-SCC-PH and its structural analog, 4A3-SCC-10, also demonstrated significantly enhanced mRNA delivery efficacy compared to their non-disulfide-containing parent compounds and disulfide-containing controls with modified lipid tails.

200Oi10 is a highly potent, biodegradable ionizable lipidoid optimized for targeted mRNA delivery, with its organ tropism dynamic to the route of administration. Under intravenous injection, it demonstrates an extraordinary 97.7% liver specificity mediated by endogenous ApoE binding. Strikingly, shifting to intraperitoneal injection redirects its tropism, yielding up to 46.4% pancreatic targeting, which can be further boosted when co-formulated with DOTAP. Featuring ester-conjugated cleavable tails, 200Oi10 guarantees rapid metabolic clearance and negligible tissue accumulation toxicity, making it an exceptional candidate for localized pancreatic therapy and efficient hepatic gene delivery.

GVS-18-B6 is a silicon ether-based ionizable lipid (pKa:6.15) developed by Genevant, optimized for mRNA-LNP delivery, characterized by a short-chain trialkyl structure with three C10 alkyl chains (including a cis double bond) and a dimethylamino (DMA) head group linked via a 4-carbon spacer (pKa ~6.15). Its LNP formulations exhibit a narrow particle size distribution (89 nm, PDI=0.06), high mRNA encapsulation efficiency (90%), and pH-dependent surface charge (−0.11 mV at pH 7.5 vs. +2.69 mV at pH 5.5), facilitating endosomal escape. ​​In vivo​​, GVS-18-B6 demonstrated superior liver-specific mRNA expression (5.30×10⁷ pg EGFP/g liver, 2.6× higher than MC3) with minimal spleen accumulation (liver/spleen ratio 92:1 vs. MC3’s 10:1), attributed to rapid non-enzymatic hydrolysis of its silicon ether bonds. This mechanism enables near-complete hepatic clearance within 6 hours in mice and 24 hours in NHPs, avoiding long-term organ retention (MC3 retained 25% in liver after 28 days). Compared to benchmarks (MC3, SM-102, LP-01), GVS-18-B6 showed enhanced potency in RBC hemolysis assays (pH 6.2), indicating earlier endosomal membrane disruption, and maintained stability through 12-month frozen storage or repeated freeze-thaw cycles. ​​Toxicity profiling​​ revealed minimal immunogenicity (MCP-1 levels 0.58×10⁶ vs. MC3’s 1.10×10⁶) and no ALT/AST elevation or anti-PEG antibody induction in NHPs after repeated dosing. Its species-agnostic clearance, low off-target effects, and high tolerability (6 mg/kg dose in mice) position GVS-18-B6 as a leading candidate for chronic disease therapies requiring frequent mRNA administration.

Lipid 119-23 is an ionizable lipid for mRNA delivery. 119-23 LNP exhibits an enhanced capability to express functional mCre in several categories of immune cells, spanning the liver, spleen and lung.

A4B4-S3 is a novel biodegradable ionizable lipid that has been meticulously designed through modular platforms and optimized specifically for mRNA delivery. It serves as a critical component of lipid nanoparticles (LNPs) and enhances mRNA delivery efficiency by facilitating endosomal escape. The structural design of A4B4-S3 leverages the Passerini reaction, a highly efficient and modular chemical method that enables the rapid generation of diverse lipid libraries. The design focuses on optimizing the methylene units between lipid headgroups and linkages to strengthen hydrogen bonding interactions with mRNA ribophosphate complexes. This enhanced hydrogen bonding allows for more effective release of mRNA from endosomes, thereby boosting delivery efficiency. Concurrently, the structural optimization improves biodegradability, reducing potential long-term toxicity risks. In experimental studies, A4B4-S3 has demonstrated superior gene editing efficacy in mouse liver compared to SM-102, a clinically prevalent lipid used in Moderna's COVID-19 vaccine. It also shows potential for repeat-dose protein replacement therapies, suggesting enhanced stability and safety for long-term treatment regimens. Technologically, A4B4-S3 not only provides a more efficient LNP formulation but also deepens the understanding of the relationship between structure and delivery efficiency. This offers new directions for the development of future mRNA therapeutics. In summary, A4B4-S3 represents a next-generation delivery carrier achieved through rational design and high-throughput screening strategies. Its performance enhancements and biodegradable properties position it as a promising candidate for gene therapies and vaccine applications.

CF3-2N6-UC18​​ is a rationally designed chloroquine-inspired ionizable lipid that enables robust mRNA delivery and genome editing. It integrates three modular components: a 7-trifluoromethyl-substituted quinoline scaffold (mimicking chloroquine’s endosomolytic properties), a hexamethylenediamine linker with two ionizable nitrogen atoms (pH-responsive protonation), and two unsaturated oleyl (C18:1) hydrophobic tails (enhancing membrane fusion and nanoparticle stability). This lipid self-assembles into ecoLNPs (endosomolytic chloroquine-like lipid nanoparticles) with spherical morphology (~200 nm diameter, 98% mRNA encapsulation). Its pH-sensitive activity triggers endosomal escape through dual mechanisms: ​​proton sponge effect​​ (buffering endo-lysosomal pH) and ​​saposin B-mediated membrane disruption​​ (molecular docking confirms chloroquine-like binding to lysosomal saposin B). In vitro, ecoLNPs outperform commercial reagents (18.9-fold higher mRNA delivery than Lipofectamine 2000) and penetrate 3D cell models. They resist serum/RNase degradation and retain >90% activity after 7-day storage at 4°C. In vivo, ecoLNPs achieve tissue-specific mRNA expression via multiple routes (intravenous, intramuscular, etc.), with strong lymph node tropism (90.2% after intramuscular injection) comparable to SM-102 LNPs (Moderna’s COVID-19 vaccine carrier). They mediate efficient Cre mRNA-driven recombination and CRISPR-Cas9 editing in transgenic mice. CF3-2N6-UC18’s modular design, stability, and dual endosomal escape strategies position it as a versatile platform for mRNA vaccines, gene therapy, and genome editing applications.

AO12 is a novel antioxidant ionizable lipid derived from SM-102 skeleton with para-hydroxyphenyl propionic acid side chains. Integrated into LNPs, it efficiently scavenges diverse reactive oxygen species including ·OH and ONOO⁻, shielding encapsulated mRNA from oxidative degradation. It retains fine LNP formulation features and cellular uptake capacity of conventional lipids, boosting in vivo mRNA translation. Applied for regenerative mRNA therapy and CRISPR gene editing against fibrosis and inflammatory disorders.

AA-T3A-C12 is a leading anisamide-tethered lipidoid (AA-lipidoid) identified through a combinatorial library screening for targeted RNA delivery to activated fibroblasts, offering a promising approach to treat liver fibrosis.AA-T3A-C12 is a leading anisamide-tethered lipidoid (AA-lipidoid) identified through a combinatorial library screening for targeted RNA delivery to activated fibroblasts, offering a promising approach to treat liver fibrosis. It is synthesized via a one-pot, two-step modular method that combines anisamide—a ligand for sigma receptors overexpressed on activated hepatic stellate cells (HSCs)—with a T3A polyamine core and C12 epoxide tails, enabling efficient siRNA encapsulation in lipid nanoparticles (LNPs). In vitro, AA-T3A-C12 LNPs exhibit enhanced cellular uptake and gene silencing in activated fibroblasts, dependent on sigma receptor binding, as confirmed by haloperidol blockade studies, and outperform non-targeted analogs and the FDA-approved MC3 LNPs in fibroblast selectivity.In a mouse model of CCl4-induced liver fibrosis, AA-T3A-C12/siHSP47 LNP achieves approximately 65% knockdown of heat shock protein 47 (HSP47), a key fibrotic target, leading to significant reduction in collagen deposition and fibrosis alleviation, with a good safety profile and no exacerbation of liver injury.

VL-422 is an ionizable cationic lipid. VL-422 delivers CRISPR complementary single-guide RNA (sgRNA) and Cas9 mRNA to enable in vitro and in vivo gene editing. LNPs containing VL-422 loaded with Cas9 mRNA and sgRNA targeting the ANGPTL3 gene induce the deletion of premature stop codons within the ANGPTL3 gene in the liver of cynomolgus monkeys. Loss-of-function of ANGPTL3 leads to decreased levels of LDL, HDL and cholesterol in plasma. The VL-422 delivery system can be used for the research of gene editing strategies targeting lipid metabolism diseases.

YSK 12C4 is an ionizable cationic lipid primarily used to enhance siRNA cellular delivery via multifunctional envelope-type nanodevices (MEND). YSK 12C4 promotes siRNA uptake and endosomal escape, effectively silencing genes in human immune cell lines.

Acuitas Lipid III-25 is an novel ionizable amine lipid used for mRNA delivery from Acuitas Therapeutics patent US 10,166,298 B2, with pKa 6.22, Liver Luc 1648 for 0.3mgkg(ng luc/g liver), Liver Luc 13880 for 1mgkg(ng luc/g liver) . It is an analgous of ALC-0315, showing higher activity than ALC-0315.

MoChol is a cationic cholesterol derivative used as a membrane component in charge-reversible amphoteric nanoliposomes. It has been incorporated with CHEMS, DOPE and POPC into liposomal formulations for the delivery of anti-BCL-2 antisense oligonucleotides.

BiP-20 is a branched ionizable phospholipid identified as a lead compound for efficient hepatic mRNA delivery.BiP-20 is a novel, efficient, and safe liver-targeted LNP delivery vehicle. With an ideal pKa of 6.56, it achieves highly efficient liver targeting and endosomal escape primarily through the ApoE/LDL-R pathway. It demonstrates exceptional performance in gene editing at very low doses: for CRISPR-Cas9-mediated editing of TTR, a 10 μg dose achieved ~64% efficiency, which is 8-fold higher than the clinical benchmark lipid LP-01. In Prime Editing targeting the PCSK9 gene, its efficiency (4.30%) also significantly surpassed that of MC3, SM102, and LPO1. Furthermore, it mediates a 5.9-fold increase in hepatic protein expression compared to MC3. Safety assessments indicate it does not induce liver function abnormalities, showing strong therapeutic potential.

Lipid A10 (CSS-A10) is a diketopiperazine-core ionizable lipid used in the LNP67 formulation for mRNA delivery to hematopoietic stem and progenitor cells. In the cited study, ligand-free LNP67 delivered reporter mRNA to mouse bone-marrow HSC/HSPC populations and to CD34+ cells in young rhesus monkeys after intravenous administration.

CSL3 is a pH-switchable cationic lipid optimized for siRNA LNP delivery. Its core design features central pyridine and two ortho-methoxy groups, forming intramolecular hydrogen bonds under endosomal pH 5–6 to trigger conformational flip, which drives membrane fusion and efficient endosomal escape—an advantage absent in control lipid CSL4 without methoxy moieties. Formulated with DSPC, cholesterol and DMG-PEG2000 at a fixed molar ratio, CSL3-based LNPs achieve 85–95% siRNA encapsulation, uniform particle size and decent serum stability. In vitro tests show potent gene silencing with low cytotoxicity; in vivo intravenous administration enables obvious liver accumulation and dose-dependent Factor VII knockdown in mice, proving its great potential for hepatic RNAi therapeutic research.

98N12-5 is an ionizable cationic lipid. It has been used in combination with other lipids in the generation of lipid nanoparticles (LNPs). LNPs containing 98N12-5 and encapsulating proprotein convertase subtilisin kexin type 9 (PCSK9) siRNA selectively accumulate in the liver and reduce total serum cholesterol levels in mice and rats and serum LDL levels in cynomolgus monkeys.

YSK 05 is a pH-sensitive cationic lipid. YSK 05 improves the intracellular trafficking of non-viral vectors. YSK 05-MEND shows significantly good gene silencing activity and hemolytic activity. YSK 05 overcomes the suppression of endosomal escape by PEGylation. YSK 05 effectively enhances siRNA delivery both in vitro and in vivo.

Lipid A6 is an ionizable cationic and biodegradable alkyne lipid (pKa = 6.65).It has been used with other lipids in the formation of lipid nanoparticles (LNPs) for the delivery of mRNA. LNPs containing lipid A6 and encapsulating mRNA encoding human erythropoietin (EPO) increase and then maintain homeostatic levels of hemoglobin in the blood in an adenine-induced mouse model of renal anemia.

113-O12B LNP, an LN-targeting LNP delivery system, is developed for a mRNA cancer vaccine.

306Oi10 is a branched ionizable lipid that can be used to construct lipid nanoparticles (LNPs) for delivering messenger RNA. The surface ionization of lipid nanoparticles is related to the effectiveness of mRNA delivery. The tail of 306Oi10 has a one-carbon branch, which provides it with stronger surface ionization compared to lipids with linear tails, thereby enhancing its mRNA delivery efficacy. 306Oi10 can be used in research related to mRNA delivery.

4A3-SC8 is a novel Ionizable amino lipid for RNA delivery.The CRISPR-Cas9 gene editing system has been a hotspot in the field of gene therapy, especially the gene correction induced by homology-directed repair (HDR). However, its application has various obstacles, such as large molecular weight, poor stability, off-target risk, and the complexity of codeliver multiple genes. Farbiak et al. established a novel ionizable lipid library consisting of four distinct amine cores (3A3, 3A5, 4A1, 4A3) and nine peripheries with different alkyl chain lengths (SC5-SC14), and screened out a class of iLNPs with ability of encapsulating Cas9 mRNA, sgRNA and donor DNA simultaneously. The delivery efficiency (quantified by luciferase mRNA expression) and iLNPs toxicity were evaluated with three different cell lines (HEK293T, HeLa, and IGROV-1), indicating the formulation containing 4A3-SC8 was the best. 4A3-SC8 iLNPs successfully induced HDR in HEK293 cells by one-pot delivery of Cas9 mRNA, sgRNA, and the correct ssDNA template. Confocal microscopy imaging showed that a portion of blue fluorescence in cells was corrected to green fluorescence. Furthermore, the nucleic acid ratios of Cas9: sgRNA: donor DNA loading in iLNPs at a ratio of 2:1:3 could maximize the HDR efficiency with the editing efficiency up to 23%, which breaks through the current bottleneck of HDR efficiency of only 1–5%. This progress is undoubtedly an important advance in the gene therapy field to cure diseases caused by genetic mutations.

306-O12B-3 is an ionizable lipidoid with cationic properties, commonly used in lipid nanoparticle (LNP) formulations for antisense oligonucleotide (ASO) delivery. When administered intravenously in mice, LNPs incorporating 306-O12B-3 exhibit liver-specific accumulation. Studies show that ASO-loaded LNPs containing 306-O12B-3 effectively silence hepatic PCSK9 expression by targeting the proprotein convertase subtilisin/kexin type 9 gene. Additionally, when combined with the cationic lipidoid NT1-O14B (Item No. 37095), these LNPs can deliver tau-targeting ASOs to the brain, reducing tau protein levels in mice.

PPZ-A10 is an ionizable cationic lipid.It has been used in the generation of lipid nanoparticles (LNPs) for the delivery of siRNA and mRNA in vitro and in vivo. Intraperitoneal administration of LNPs containing PPZ-A10 and encapsulating an mRNA reporter preferentially accumulates in hepatic Kupffer cells and splenic macrophages in mice.

ND-O1 (SM-86 Analog-2) is a novel ionizable lipid designed to improve the delivery of siRNA via lipid nanoparticles (LNPs) for treating liver fibrosis. It is derived from SM-86 (structurally similar to SM-102, used in COVID-19 mRNA vaccines) but incorporates an ether bond within its hydrophobic tail, a first-of-its-kind modification aimed at enhancing delivery efficiency. In Vitro Efficiency: ND-O1 LNPs (LNP-O1) showed significantly higher siRNA transfection efficiency in activated fibroblasts compared to Lipid 5 LNPs (LNP-M). In Vivo Efficacy: In a CCl4-induced liver fibrosis mouse model, LNP-O1/siHSP47 (loaded with HSP47-targeting siRNA) reduced HSP47 expression by ~84%, threefold more effective than LNP-M. This led to a dramatic reduction in collagen deposition and marked improvement in liver fibrosis. Safety: The ether bond modification did not introduce additional toxicity, maintaining biocompatibility. ND-O1 represents a breakthrough in ionizable lipid design, demonstrating that strategic placement of ether bonds in hydrophobic tails can enhance LNP performance without compromising safety. Its success highlights its potential for clinical translation in RNA-based therapies for liver fibrosis and other hepatic diseases.

OF-02 (OF-2) is an alkenyl amino alcohol (AAA) ionizable lipid for highly potent in vivo mRNA delivery.Alkenyl amino alcohols (AAA) are a functional group found in sphingosine and other bioactive molecules. It was used to prepare AAA-based ionizable lipids through ring-opening reactions between alkenyl epoxides (AEs) and polyamine cores. These AAA-based iLNPs could promote high-level protein expression Therefore, AAA-based ionizable lipids OF-00, OF-01, OF-02, and OF-03 were prepared. The results of in vivo delivery of human erythropoietin (hEPO) mRNA showed that the AAA ionizable lipid OF-02 with the linoleic acid derivative could effectively deliver hEPO mRNA. Compared with the positive control CKK-E12, OF-02 showed an increased ability to induce serum EPO protein expression by nearly twofold (Figure 7b). Likewise, it outperformed two benchmark ionizable lipids (503013 and C12-200) in the nucleic acid delivery field. Furthermore, the mRNA delivered by OF-02 iLNPs was mainly in vivo.translated into the liver. The liver-targeting ability of OF-02 iLNPs improves their delivery efficiency. Therefore, the OF-02 iLNPs may become excellent delivery vehicles for the treatment of liver diseases without other side effects of damage to other organs during the treatment

CL15F 9-5, a piperidine-based ionizable lipid, exhibits favorable properties for mRNA delivery in lipid nanoparticles (LNPs). Its apparent pKa ranges between 6.24–7.15, ideal for mRNA encapsulation and endosomal escape. LNPs formulated with CL15F 9-5 (50:38.5:10:1.5 molar ratio of ionizable lipid:cholesterol:DSPC:DMG-PEG2k) demonstrated high mRNA encapsulation efficiency (>90%) and maintained physicochemical stability (size, PDI, zeta potential) during storage at 4°C for 5 months . In vitro, CL15F 9-5 LNPs showed superior luciferase expression in HEK-293T cells compared to CL4F-based LNPs. In vivo, liver-targeted LNPs delivered hEPO mRNA effectively, with sustained serum hEPO levels post-storage. Intravenous administration of FLuc mRNA-loaded CL15F 9-5 LNPs yielded strong hepatic bioluminescence, confirming liver tropism. As a vaccine candidate, CL15F 9-5 induced robust antigen-specific cellular immunity in mice, with a 14-fold increase in IFN-γ spots compared to SM-102. Its enhanced stability is attributed to reduced aldehyde impurities, minimizing mRNA-lipid adduct formation.

4A3-SC7​​ is a proprietary, ionizable lipid component central to the SORT LNP platform developed for targeted organ delivery. It features a unique ​​branched-tail structure​​ designed to enhance mRNA encapsulation and endosomal escape. In the study, it served as the ​​primary ionizable lipid​​ in both Liver SORT LNPs and updated Lung SORT LNPs. For liver targeting, it was formulated at ​​15.04 mol%​​ alongside helper lipids (DOPE: 23.04%, Cholesterol: 38.72%), PEG-lipid (DMG-PEG2000: 3.2%), and the liver-targeting lipid ​​4A3-Cit (20 mol%)​​. This specific composition (Total lipid:RNA = 20:1 wt/wt) yielded LNPs with ​​~74 nm size​​, ​​low PDI (0.17)​​, and ​​high encapsulation efficiency (87%)​​ for large mRNAs like ABE editors (~5000 nt). Its branched-tail architecture was critical for stabilizing nanoparticles encapsulating large RNAs, overcoming a key limitation of previous formulations. 4A3-SC7-based Liver SORT LNPs enabled ​​>40% base editing in hepatocytes​​ in vivo, achieving durable correction of the disease-causing SERPINA1 mutation in PiZ mice and significantly reducing pathological protein aggregates. In the updated DualSORT system, 4A3-SC7 was also paired with ​​DORI​​ (instead of DOTAP) for improved lung targeting, demonstrating its versatility as a foundational ionizable lipid for multi-organ gene editing therapeutics.

306-N16B is a lipidnanoparticle, and allows systemic codelivery of Cas9 mRNA and sgRNA. 306-N16B can transport mRNA to the pulmonaryendothelial cell. 306-N16B can be used for research of genome editing-based therapies. Based on the same lipid libraries with 306-O12B, the researchers also found that N-series ionizable lipids were able to selectively deliver mRNA to the lungs of mice. Compared with the liver-targeted O-series ionizable lipids which contained ester bond in lipid tail found in previous work, such as 306-O12B, the N-series ionizable lipids with the lipid tail containing amide bond prefer to deliver mRNA to the lung. As a N-series ionizable lipid, the chemical structure of the 306-N16B is shown in Figure 4a,b. The difference of organ targeting may be due to their adsorption of different protein coronas during blood circulation caused by their different structures mentioned earlier.It has shown that the second major protein of the protein corona adsorbed by liver-targeting 306-O12B iLNPs was apolipoprotein E (ApoE), while the three dominant proteins in the protein corona adsorbed by lung-targeting 306-N16B iLNPs were serum albumin, fibrinogen beta chain, and fibrinogen gamma chain. However, the 306-N16B iLNPs showed less organ selectivity when systematically codelivered Cas9 mRNA and sgRNA in vivo, which could simultaneously activate tdTomato expression in the liver and lung of Ai14 mice, whereas single mRNA delivery could almost exclusively deliver mRNA to the lungs. This surprising phenomenon requires further investigation. Both the change of iLNPs charge and the change of lipids functional group can influence the distribution of iLNPs in vivo due to the altering of protein corona composition. Therefore, it is possible to control the organ targeting of iLNPs by controlling the composition of the outer protein corona of iLNPs.

L1 is a biodegradable, branched self-immolative lipid optimized for ​​high-efficiency mRNA delivery​​. Its disulfide-based architecture enables rapid glutathione-triggered degradation in the cytosol (liver half-life: 4.2 days), promoting rapid clearance while maintaining serum stability. In vivo, L1 achieves ​​exceptional mRNA translation​​, producing twice the hEPO protein levels of the clinically approved MC3 lipid at 0.1 mg/kg. Its reported apparent pKa is 6.57. Tolerability is dose-dependent: supplementary clinical observations record abnormalities at 5 mg/kg through 48 hours; these findings should be considered alongside body-weight and cytokine measurements. Structural features (C7 alkyl tails, carbamate linker) balance potency and biodegradability, making L1 ideal for mRNA vaccines and protein-replacement therapies.

304O13 is a novel Biodegradable lipidoid for RNA delivery.

Lipid 20b​​ is a thiophene-based ionizable lipid synthesized via the Gewald reaction. It features dual unsaturated linoleic tails (C18:2) attached to the same side of the thiophene core and a tertiary amine headgroup. Formulated into LNPs (~100 nm, PDI ~0.2) with DSPC/cholesterol/DMG-PEG, it exhibits high mRNA encapsulation (>90%). Unlike traditional lipids, 20b lacks a pH-dependent ionization profile, likely due to electron delocalization in the thiophene ring. Intravenously, 20b LNPs transfect the liver and spleen in mice. Notably, subretinal delivery in mice and non-human primates (NHPs) achieved robust mRNA expression in photoreceptors (35% rods, 45% cones at high dose) and retinal pigment epithelium (RPE) with minimal acute toxicity. Immunosuppression enhanced rod transfection efficiency. High-dose administration in NHPs caused subretinal debris, but low doses (2.5 µg mRNA) maintained retinal health. This lipid demonstrates potential for liver and retinal gene therapy.

C10-200-based LNPs show enhanced liver tropism for mRNA delivery, outperforming branched-chain lipidoids (e.g., C12-200) in hepatic reporter gene expression. The system's therapeutic potential is confirmed through successful EPO production, with measurable increases in circulating protein levels following administration.

Lipid 5D8 is a novel biodegradable ionizable lipid (IL) developed through a combinatorial chemistry strategy to overcome the limitations of conventional lipid nanoparticles (LNPs) in mRNA delivery. Synthesized via a one-step, solvent-free Michael addition reaction between amine and thiol monomers, 5D8 features asymmetric lipid tails and a biodegradable ester backbone, ensuring both structural versatility and reduced toxicity. In preclinical studies, 5D8-based LNPs demonstrated exceptional liver-targeting efficiency and mRNA delivery performance. A single intravenous dose (1 mg/kg) achieved 61% CRISPR-Cas9-mediated editing of the TTR gene in mice, reducing serum TTR protein by 90%, outperforming benchmark lipids like C12-200 (51% editing). Moreover, 5D8 enabled efficient delivery of base editors (ABE8.8 and CBE4max), achieving 42% PCSK9 editing (74% serum protein reduction) and correcting hereditary tyrosinemia in mice, significantly extending survival. Beyond gene editing, 5D8 LNPs effectively delivered siRNA (complete serum TTR clearance at 0.05 mg/kg) and enhanced hepatocyte targeting by enriching apolipoprotein E on particle surfaces. Crucially, 5D8 exhibited superior biocompatibility with no hepatotoxicity (normal ALT/AST levels), contrasting traditional LNPs. Its rapid biodegradability and "plug-and-play" design make 5D8 a versatile platform for mRNA therapeutics, holding broad potential for treating genetic disorders, cardiovascular diseases, and beyond. This innovation represents a critical advancement toward safer, high-efficiency clinical translation of gene-editing therapies.L

Lipid 17 is a novel, highly potent ionizable lipid designed for mRNA delivery within lipid nanoparticles (LNPs) developed by AstraZeneca . Its structure features a secondary amine head group attached to a cyclic ether moiety (specifically, the 2-oxaspiro[3.3]heptan-6-amine head group). It possesses an asymmetric tail architecture: one tail is derived from heptadecan-9-ol (a branched C17 secondary alcohol), while the other tail is a modified nonyl chain (C9) with a key ethyl branch at the 3-position. The linker connecting the head group to the tails has a length equivalent to n=3 (three methylene units) as defined in the study. This specific combination of the secondary amine cyclic ether head group, asymmetric tails, and the ethyl branch at the 3-position of the nonyl chain proved critical for its exceptional performance. When formulated into LNPs and administered intravenously in mice, Lipid 17 demonstrated a remarkable 6-fold increase in functional protein (eGFP) expression in the liver compared to the benchmark lipid MC3, with high statistical significance (P < 0.0001). This makes Lipid 17 one of the most active lipids identified in the study and a promising candidate for liver-targeted mRNA therapeutics.​​

4A3-LNSC8​ is a strategically designed thiourea-functionalized ionizable lipid that serves as the foundational core for a novel anion-coordination delivery platform. Its structure features a central 4A3 amine headgroup symmetrically extended with four hydrophobic tails, each incorporating a biodegradable ester linkage and a key thiourea-bridged linker. The inclusion of the thiourea group is the pivotal innovation, as it provides specific hydrogen-bonding sites capable of interacting with various halide anions (F⁻, Cl⁻, I⁻). When formulated into lipid nanoparticles (LNPs) without anion coordination, 4A3-LNSC8 itself exhibits a characteristic liver tropism, efficiently delivering mRNA to hepatocytes following systemic administration, with a measured surface pKa of approximately 5.54. However, its primary significance lies in its role as a versatile precursor. The strong anion-binding capability of its thiourea linkers allows for predictable modulation of the LNP's properties. Upon binding with anions like Cl⁻, the resulting complex (e.g., Cl-4A3-LNSC8) undergoes a significant pKa shift, which reprograms the LNP's in vivo fate, redirecting mRNA delivery from the liver to secondary lymphoid organs such as the spleen and lymph nodes. Thus, 4A3-LNSC8 is not merely an efficient ionizable lipid but a programmable scaffold that enables precise control over organ-targeting specificity through simple anion coordination, offering a powerful rational design strategy for advanced mRNA therapeutics.

244-9-cis is a novel ionizable lipid disclosed in United States Patent US 2026/0014075 A1, specifically engineered for advanced lipid nanoparticle (LNP) delivery systems. Its distinctive molecular architecture features biodegradable ester bonds, which contribute to excellent physicochemical properties such as a near-neutral surface charge (approximately -3 mV) for improved biocompatibility, an optimal pKa of about 6.2 to facilitate endosomal escape, and consistently high nucleic acid encapsulation efficiency exceeding 90%. In vivo studies confirm significantly enhanced delivery to hepatocytes and markedly higher therapeutic protein expression compared to control formulations, positioning 244-9-cis as a promising candidate for next-generation genetic medicines.

GA-16 is a novel ionizable lipid designed with an N-(2-Hydroxyethyl)piperazine-N'-(4-butanesulfonic acid) (HEPBS) core. Its key functional characteristic is enabling highly efficient, liver-tropic mRNA delivery through an ApoE-mediated yet Low-Density Lipoprotein Receptor (LDLR)-independent cellular uptake mechanism. When formulated in LNPs with the helper lipid DEPE, GA-16 achieves superior protein expression. More importantly, this uptake pathway bypasses the canonical LDLR dependency, making it a strategically valuable component for developing therapies targeting genetic liver diseases like familial hypercholesterolemia, where patients often have deficient LDLR function.

M10 is a piperazine-derived bis-tertiary amine ionizable lipid. With an optimal pKa of 6.56, it enables efficient liver-targeted CRISPR/Cas9 delivery, achieving durable PCSK9 silencing and LDL-C reduction after a single dose, alongside a favorable safety profile.

HGT5001, disclosed in patent US 2026/0125339 A1 by Translate Bio (now part of Sanofi), is a potent ionizable cationic lipid optimized for mRNA delivery, exhibiting versatile organ tropism governed by the route of administration. When delivered via intratracheal or pulmonary administration, it effectively crosses the mucosal barrier to achieve high transfection efficiency specifically within lung tissues. Conversely, intravenous injection redirects its tropism to the liver and spleen via endogenous ApoE mediation, facilitating systemic protein replacement therapies. Engineered with an optimized headgroup, HGT5001 ensures excellent encapsulation, rapid pH-responsive endosomal escape, and superior biocompatibility with minimal systemic toxicity, making it an exceptional candidate for cystic fibrosis therapies and hepatic treatments.

TT3 is an ionizable cationic amino lipid that has been used in combination with other lipids in the formation of lipid-like nanoparticles (LLNs). Administration of LLNs containing TT3 and encapsulating mRNA encoding human coagulation Factor IX induces human coagulation Factor IX expression in the plasma of mice.

E4i-200 is a branched ionizable lipid designed for efficient mRNA and CRISPR-Cas9 delivery. It features a 4-carbon (C4) lipid tail with an isopropyl (i) branch at the terminal position, enhancing its ability to disrupt endosomal membranes. The lipid is built around the 200 core, a polyamine structure (N1-(2-(4-(2-aminoethyl)piperazin-1-yl)ethyl)ethane-1,2-diamine), which facilitates mRNA encapsulation and delivery. E4i-200 excels in liver-targeted delivery, significantly improving mRNA translation and gene editing efficiency in vivo. In experiments, it outperformed linear lipids, achieving 1.5-fold higher liver luminescence compared to the gold standard C12-200. Its isopropyl branch promotes deeper membrane penetration, enhancing endosomal escape and cargo release. This lipid is particularly effective for hepatic gene editing, reducing target gene expression (e.g., TTR) by up to 90% in mouse models. Its modular design and low toxicity make it a promising candidate for mRNA-based therapies and CRISPR applications in the liver.

E8i-200 is a novel Branched Endosomal Disruptor (BEND) ionizable lipid, designed to enhance the efficiency of lipid nanoparticles (LNPs) in drug delivery, particularly for mRNA and protein delivery. Its unique structure, featuring terminal branching, improves endosomal escape, a critical step in the delivery of therapeutic cargo into cells.E8i-200 is designed to enhance endosomal escape, a key bottleneck in mRNA and protein delivery. Its terminal branching structure provides several advantages:Improved Endosomal Membrane Penetration: The branched structure allows E8i-200 to more effectively disrupt endosomal membranes, facilitating the release of mRNA and proteins into the cytoplasm.Enhanced Gene Editing Efficiency: E8i-200 has been shown to significantly improve the delivery of CRISPR-Cas9 ribonucleoprotein (RNP) complexes, enabling efficient gene editing in vivo.E8i-200 significantly enhanced mRNA expression in the liver, outperforming traditional linear lipids like C12-200 in mouse models.E8i-200 effectively delivered CRISPR-Cas9 RNP complexes, achieving high editing efficiency in the liver, surpassing that of linear lipids.E8i-200 also showed high transfection efficiency and low cytotoxicity in T cells, making it a promising candidate for CAR-T cell engineering and other immunotherapies.

O12-D3-I3 is an imidazole-based lipid for siRNA delivery. O12-D3-I3-LNPs encapsulating FVII siRNA (FVII@O-LNP) elicites greater gene silencing than those with the DLin-MC3-DMA (MC3) due to its stronger endosomal escape.

12T-O14 is a amidine-incorporated degradable (AID) lipid for versatile mRNA delivery. 12T-O14-LNPs mediate efficient intramuscular delivery of mRNA vaccines and systemic delivery of mRNA therapeutics without noticeable toxicity. 12T-O14 serves as a superior supplementary lipid to redirect liver-tropic LNPs to selectively target the lung or spleen via simple adjustment of the formulation.

Si6-C14b is a siloxane-incorporated lipid for livertargeting mRNA delivery. The siloxane moieties enhance cellular internalization of mRNA-LNPs and improve their endosomal escape capacity, augmenting their mRNA delivery efficacy.

CL4F11_ζ-2 is an ionizable lipid for hepatic delivery of CRISPR/Cas ribonucleoprotein (RNP). CL4F11_ζ-2 LNP shows an extremely strong inhibitory effect of serum TTR protein levels compared with all the approved ionizable lipids including DLin-MC3-DMA (MC3), SM-102, and ALC-0315.

THP1 is a tetrahydropyrimidine ionizable lipid for mRNA delivery. THP1 demonstrates higher transfection efficiency comparable to DLin-MC3-DMA (MC3). THP1 LNPs also demonstrates the ability to edit genes in specific liver tissues in a tdTomato transgenic mouse model.

31hP is an asymmetric A3-lipid for mRNA delivery. 31hP LNP exhibits higher stability and durability compared with MC3 LNP and SM-102 LNP. 31hP LNP achieves more efficient hepatic mRNA delivery with a much higher gene editing efficiency than MC3 LNP and LP01 LNP.

A2C18_D5 is an optimized lipid nanoparticle (LNP) component engineered with structural modifications to enhance mRNA delivery efficiency and safety. Its design incorporates a hydrophobic head group (A2, featuring a pentyl chain) and an unsaturated C18 tail, which collectively lower its pKa to the ideal range of 6–7, enabling stable encapsulation of nucleic acids and improved endosomal escape. In vitro and in vivo studies demonstrate that A2C18_D5 achieves mRNA delivery efficiency comparable to the clinically approved LNP benchmark MC3, while exhibiting over 200-fold higher potency than its precursor lipid (A1C11). The lipid’s reduced protonation capacity minimizes cytotoxicity and hemolytic risk, aligning with safety profiles of established LNPs. Upon intravenous administration, A2C18_D5 predominantly targets the liver and spleen, with a biodistribution profile favoring hepatic delivery. Its balanced combination of high transfection efficiency, low toxicity, and favorable pharmacokinetics positions A2C18_D5 as a promising candidate for next-generation mRNA therapeutics, including vaccines and treatments for liver-specific diseases. Further optimization of its head-tail structure highlights its versatility for tailored delivery applications.

4A3-Cit is an ionizable lipid used for the generation of lipid nanoparticles (LNPs). To investigate the role of unsaturated lipid tails in iLNPs, the nucleophilic amines were added to ester-based linkers, followed by Michael’s addition to the thiols to construct a library of 91 amino ionizable lipids. Such ionizable lipids were composed of an ionizable tertiary amine core, an ester-based degradable linker, and an alkylthiol tail periphery. Through in vitro and in vivo screening, the iLNPs with 4A3 core and citronellolbased (Cit) periphery can significantly increase endosome escape and delivery efficiency of mRNA, leading to 18-fold increase in protein expression compared with iLNPs without Cit periphery. Furthermore, the delivery efficiency of mRNA may be associated with the location/configuration of the unsaturated bond(s) in lipids. Although lipids with Cit periphery showed excellent membrane fusion ability to facilitate endosome escape, the fusion mechanism needs to be further clarified.

cKK-E15 is an ionizable cationic lipid and a derivative of cKK-E12 that has been used in the generation of lipid nanoparticles (LNPs).1 LNPs containing cKK-E15 and encapsulating Cre mRNA induce the expression of Cre in Kupffer cells, endothelial cells, and hepatocytes in Ai14 mice engineered to express the fluorescent protein tdTomato upon translation of Cre.

9A1P9 is a multi-tail ionizable cationic phospholipid. 9A1P9 induces membrane destabilization. 9A1P9 can be used for CRISPR-Cas9 gene editing in mice.

C9-200 is an ionizable cationic lipid that has been used in the formation of lipid nanoparticles (LNPs). LNPs containing C9-200 and encapsulating mRNA encoding erythropoietin (EPO) increase serum EPO levels in mice. LNPs containing C9-200 and encapsulating mRNA encoding the Cas9 nuclease and small-guide RNA (sgRNA) targeting transthyretin (TTR) induce 3-fold higher hepatic insertion and deletion (indel) formation than LNPs containing C12-200 and encapsulating mRNA encoding Cas9 in mice.

C14-490 is an ionizable cationic lipid (pKa = 5.94).1 It has been used in the generation of lipid nanoparticles (LNPs) for the delivery of mRNA in vivo.C14-490-containing LNPs accumulate primarily in the fetal mouse liver and, to a lesser extent, in the lungs, intestine, and brain after vitelline vein injection on gestational day 16 (E16).1 CD45-functionalized LNPs containing C14-490 and encapsulating mRNA encoding GFP transfect Jurkat cells, which constitutively express the CD45 receptor (CD45R).C14-490-containing CD45-functionalized LNPs encapsulating Cre mRNA mediate genome modulation in bone marrow hematopoietic stem cells (HSCs) for at least four months after in utero injection in R26mT/mG mice at E13.5.

9C-SCC-10 is a biodegradable ionizable lipid with a nine-membered triaza crown-like headgroup and three disulfide-containing hydrophobic arms. In the cited mouse study, LNPs containing uncomplexed 9C-SCC-10 showed liver-biased mRNA-derived expression and an apparent LNP pKa of 6.42. Coordination with zinc produced the distinct Zn-9C-SCC-10 system, which shifted expression toward the lung. DC67451 refers to the uncomplexed lipid; the zinc-coordinated formulation is described separately in the literature analysis.

Lipid 114 (pKa ~6.8) is an ionizable cationic lipid optimized for siRNA delivery via LNPs, demonstrating predominant hepatic accumulation with secondary renal uptake in murine models. When formulated with IL-1β-targeting siRNA, these LNPs effectively suppress pro-inflammatory cytokine expression in both macrophage cell lines and primary cells in a dose-dependent manner. In LPS/galactosamine-induced acute liver failure models, the therapeutic LNPs significantly reduce IL-1β levels in target organs while attenuating hepatic inflammation and injury markers.

BCP-NC2-C12 is an ionizable cationic lipid designed for mRNA delivery, forming LNPs that predominantly localize to hepatic and splenic tissues in vivo. When formulated with CRISPR-Cas9 components (Cas9 mRNA and Pcsk9-targeting sgRNA), these LNPs effectively generate gene-editing indels and significantly lower circulating PCSK9 levels in murine models.

​​nor-MC3​​ is a novel ionizable lipid develoed by Nanovation, derived from the MC3 structural framework, characterized by two ​​C17 alkyl chains​​ (each containing two Z-geometry double bonds) conjugated to a ​​4-(dimethylamino)butanoate​​ headgroup. Synthesized via a streamlined route involving Claisen condensation of methyl linoleate, hydrolysis/decarboxylation to generate a C17 ketone, reduction to the corresponding alcohol, and final esterification with 4-(dimethylamino)butanoic acid, nor-MC3 retains the ionizable amine functionality critical for pH-dependent nucleic acid binding and endosomal escape. Compared to the benchmark lipid MC3 (C18 chains), nor-MC3 demonstrates ​​superior mRNA delivery efficiency​​ in vitro (2-fold higher luciferase expression at 10 μg/mL mRNA) and enhanced in vivo biodistribution (higher liver and spleen targeting in mice). Notably, its shortened C17 chains challenge conventional assumptions about optimal hydrophobic chain length, offering improved synthetic scalability while maintaining or exceeding MC3's encapsulation efficiency (~95%), nanoparticle size (~80 nm), and low polydispersity (PDI ~0.08). For siRNA delivery, nor-MC3 achieves comparable EC₅₀ values (0.1644 μg/mL vs. MC3’s 0.1308 μg/mL), highlighting its versatility as a next-generation lipid nanoparticle (LNP) component for nucleic acid therapeutics.

L2 is a redox-responsive lipid engineered for ​​ultra-potent siRNA delivery​​. With shorter hexyl (C6) tails and a carbamate linker, it demonstrates the ​​fastest biodegradation​​ (liver half-life: 2.6 days) among tested lipids. L2 achieves >80% FVII gene knockdown at just 0.01 mg/kg—surpassing both L1 and MC3 in siRNA potency. Its higher apparent pKa (6.90) enhances endosomal disruption, correlating with strong in vitro hEPO expression. While slightly less effective for mRNA than L1, L2’s unmatched siRNA silencing efficiency, rapid cytosolic self-immolation, and low cytotoxicity position it as a leading candidate for RNAi therapeutics targeting hepatic diseases.

GVS-18-B34 is a highly potent, silicon ether-based ionizable lipid that enables efficient mRNA delivery via lipid nanoparticles (LNPs). Its key advantage lies in a biodegradable silyl ether linkage, which undergoes rapid, non-enzymatic hydrolysis, leading to near-complete clearance from the liver within 24 hours in both mice and non-human primates (NHPs). This degradation mechanism is species-agnostic, overcoming the variability associated with esterase-dependent lipids. In vivo, GVS-18-B34 LNPs demonstrated superior liver-specific protein expression and a high liver-to-spleen signal ratio, indicating minimal off-target accumulation and reduced immune stimulation compared to benchmarks like MC3 and SM-102. The LNPs exhibited excellent stability when stored frozen at -80°C, maintaining integrity over multiple freeze-thaw cycles. With its optimal pKa (~6.3) and efficient endosomal escape profile, GVS-18-B34 represents a promising candidate for therapeutic applications requiring frequent dosing, combining high potency with a favorable safety profile derived from its rapid clearance.

GVS-18-B35 is a leading silicon ether-based ionizable lipid that demonstrates exceptional performance in mRNA delivery. It features a biodegradable silyl ether linkage, which undergoes rapid, non-enzymatic hydrolysis, enabling near-complete clearance from the liver within 24 hours in both mice and non-human primates (NHPs). This degradation mechanism is independent of variable enzymatic activity, ensuring consistent pharmacokinetics across species. In vivo, GVS-18-B35 lipid nanoparticles (LNPs) achieve superior liver-specific protein expression with minimal off-target accumulation in the spleen, resulting in a high liver-to-spleen signal ratio and reduced immune stimulation. The LNPs exhibit excellent stability under frozen storage (-80°C) and maintain critical quality attributes, including particle size, polydispersity, and encapsulation efficiency, through multiple freeze-thaw cycles. With an optimal pKa (~6.3) and enhanced endosomal escape capability, GVS-18-B35 represents a robust and versatile platform for mRNA therapeutics, particularly suited for applications requiring frequent dosing due to its unique combination of high potency and rapid clearance profile.

CLinDMA, a cationic lipid known to potentially trigger inflammatory responses, is utilized in the synthesis of LNP201. This liposome-based assembly is specifically designed for the systemic delivery of siRNA.

Lipid A1-D1-5 is an ionizable lipid-like substance used for RNA interference therapy in heat-stable ionizable lipid-like nanoparticles (iLAND) for the treatment of hyperlipidemia.

DMAP-BLP is a lipid for RNA and vaccine delivery.DMAP-BLP exhibits optimized bilayer destabilizing and pKa properties leading to highly potent gene silencing in hepatocytes following IV administration that is similar to “gold standard” lipids such as DLinMC3-DMA.

Lipid 23 is an ionizable cationic amino lipid (pKa = 5.7) that has been used with other lipids in the formulation of lipid nanoparticles (LNPs). Intravenous administration of LNPs containing lipid 23 and encapsulating an mRNA reporter accumulate specifically in the mouse liver.