Lipids for Spleen 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.

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.

Lipid 43 is an ionizable lipid disclosed as Compound 43 in WO 2024/109794. In the patent's TMF30 formulation, mRNA-LNPs showed predominantly splenic reporter expression after administration in mice. Its structure, molecular formula, molecular weight and SMILES were assigned from the compound-specific synthesis scheme and checked against the reported proton count.

503O8,12 is a branched-tail ionizable lipidoid prepared from amine head 503 and saturated 2-octyldodecyl acrylate. In a four-component, DOPE-containing LNP, it produced predominantly splenic reporter expression after intravenous mRNA administration in mice. It is a research candidate for extrahepatic mRNA formulation screening; cell-specific spleen delivery and therapeutic efficacy were not established in this study.

​TOT-5​​, a tri-oleoyl-Tris ionizable lipid (pKa 6.2), enables splenic B cell-targeted mRNA delivery via 15% DSPC-incorporated LNPs. Its charge-neutral, hydrophobic surface minimizes hepatic ApoE uptake and enhances complement C3 adsorption, facilitating CD21/35-mediated uptake by marginal zone B cells. In vivo, intravenous 15%DSPC-LNPs showed 8-fold higher spleen-to-liver luciferase expression vs 3%DSPC, with anti-CD21/35 blocking 60% B cell uptake. Intramuscular administration induced robust OVA-specific IgG (10^5 titer) and CTL responses (3.5% tetramer+ CD8+ T cells) while reducing hepatotoxicity (ALT/AST levels ≤40 U/L vs SM-102-LNPs' 80-120 U/L). Cryo-ET confirmed stable lamellar structures (80-100 nm, ζ-potential -2 mV). This formulation achieves safe, ligand-free splenic targeting for mRNA vaccines.

CL15F 7-5 is a piperidine-based ionizable lipid from the CL15F library, characterized by a symmetrically branched tail structure with a 7-carbon main chain and a 5-carbon side chain. This moderate tail length positions it between short-tail (e.g., CL15F 6-4) and long-tail (e.g., CL15F 14-12) variants, granting it a unique balance in mRNA delivery properties. Its LNPs exhibit optimized organ selectivity, enabling significant mRNA expression in both the spleen and muscle, as demonstrated by in vivo luciferase assays following intravenous and intramuscular administration. This lipid structure facilitates a favorable DSPC surface density on LNPs, which moderates interactions with serum proteins like ApoE, thereby reducing rapid hepatic clearance and promoting extrahepatic delivery. In vaccine applications, CL15F 7-5 LNPs encapsulating SARS-CoV-2 RBD mRNA elicited robust anti-RBD IgG titers and neutralizing antibodies in mice, outperforming the clinically benchmarked SM-102 lipid. The piperidine headgroup further contributes to storage stability by minimizing the generation of aldehyde impurities that can form mRNA-lipid adducts. Consequently, CL15F 7-5 represents a versatile lipid for developing stable, spleen-targeted mRNA vaccines and therapeutics, leveraging tail-length engineering for enhanced efficacy without complex formulation changes.

CICL 207 is structurally optimized based on Lipid CICL-1. CICL207​​ is a constrained ionizable cationic lipid designed for lipid nanoparticle (LNP) delivery systems developed by Capstan. Its structure features a ​​rigid cyclic backbone​​ (e.g., pyrrolidine-derived core) paired with a ​​tertiary amine group​​ that ionizes at acidic pH (pKa ~6.5–7.0), enhancing endosomal escape. The lipid includes ​​asymmetric hydrophobic tails​​ (likely C14–C18 alkyl/ester chains) to stabilize LNP membranes and improve nucleic acid encapsulation. Integrated into LNPs (e.g., 58% CICL-207, 10% DSPC, 30.5% cholesterol, PEG-lipids), it enables targeted delivery to T cells (anti-CD5/CD8 tLNPs) with ​​high transfection efficiency​​ (spleen T cells >70% mCherry+), ​​reduced liver uptake​​, and ​​low toxicity​​ (no significant ALT/AST elevation in rats). Its constrained design balances stability, tissue specificity, and biocompatibility for gene therapy applications.CICL 207 (F50) significantly outperforms CICL-1 by delivering dramatically enhanced target cell transfection with reduced off-target effects. It achieves >50% transfection efficiency in splenic T-cells—nearly double that of CICL-1—while slashing off-target expression in liver cells to <5% (versus >15% for CICL-1. This precision translates to superior therapeutic outcomes: CICL-207 enables ~95% B-cell depletion in CAR-T applications, far exceeding CICL-1 ’s ~60% efficacy. Critically, it maintains an exceptional safety profile, showing no significant liver toxicity or inflammatory cytokine elevation even at high doses. Furthermore, CICL-207 demonstrates 2-fold higher transfection efficiency in hematopoietic stem cells, enabling robust gene editing. Its optimized pKa (~6.5) and constrained amine structure enhance endosomal escape while minimizing Kupffer cell uptake, making it ideal for targeted therapeutics requiring both potency and safety.​

PL-40​​ is a ​​cardiolipin-mimetic ionizable lipid​​ engineered for high-efficiency, antibody-free mRNA delivery to T cells. PL 40 LNPs exhibit a mean particle size of ​​120 nm​​, zeta potential of ​​-5.19 mV​​, and >80% mRNA encapsulation efficiency, with excellent plasma stability (≤5% size change after 6h in serum). Cryo-TEM reveals ​​polyhedral nanoparticles​​ with phase-separated domains, while SAXS confirms tight mRNA packing (d-spacing: ​​~3 nm​​ vs. 6.64 nm in conventional LNPs). AFM demonstrates exceptional rigidity (high bending modulus), enabling T cell-selective uptake via actin-mediated endocytosis (>2× higher than ALC0315 LNPs).In primary human T cells, PL40 LNPs achieve ​​>90% transfection​​ at 0.5 μg mRNA dose and sustain >100× higher luciferase expression than benchmark lipids. When delivering circular RNA, they extend protein expression ​​>5 days​​ with superior spleen tropism (spleen:liver ratio = ​​2.63​​). Crucially, they reprogram T cells into functional CAR-Ts in vivo without antibody conjugation, evading exhaustion markers (no Tim-3/PD-1 upregulation). Therapeutically, PL40-based uPAR-targeted CAR mRNA reduces liver fibrosis (​​collagen↓50%​​, ALT↓50%) and rheumatoid arthritis severity (​​clinical scores↓60%​​) by clearing senescent cells. Humanized anti-uPAR CARs delivered via PL40 show near-complete cytotoxicity (>95%) against uPAR+ cells, underscoring clinical translatability.

PyCB lipid (MeDZ) is a rationally designed zwitterionic ionizable lipid that serves as a core functional component in the novel three-component (ThrCo) lipid nanoparticle (LNP) platform. It is synthesized by covalently attaching a zwitterionic PyCB structure to the hydroxyl group of the clinically available ionizable lipid ALC-0315.Its key feature is its pH-responsive behavior. At physiological pH (~7.4), the PyCB headgroup exhibits zwitterionic properties, forming charge-assisted hydrogen bonds with water molecules (PyCB-H₂O complexes). This confers high hydrophilicity to the LNP surface, enhancing stability in aqueous environments and reducing nonspecific protein adsorption in the bloodstream. This zwitterionic surface effectively mimics and replaces PEGylated lipids, thereby avoiding PEG immunogenicity and the associated Accelerated Blood Clearance (ABC) effect upon repeated administrations.Crucially, in the acidic environment of endosomes (pH ~6.5), the PyCB group undergoes strong protonation, rapidly transforming into a cationic state (PyCB-H₃O⁺ complexes). This promotes efficient fusion with and disruption of the endosomal membrane, facilitating the escape and cytoplasmic release of encapsulated mRNA.By replacing both cholesterol and PEGylated lipids in traditional LNPs, PyCB lipid enables the redirection of LNP biodistribution from the liver to the spleen, achieving superior spleen-specific mRNA translation and enhancing antigen presentation for potent immune activation.

AMG514 is a novel ionizable lipid designed for formulating spleen-targeting lipid nanoparticles (LNPs) to deliver immune‑remodeling mRNAs (IR‑mRNAs). Its key advantage lies in the formation of a unique “protein corona” enriched with vitronectin, coagulation factors, and specific apolipoproteins (e.g., ApoA‑IV), together with its relatively high apparent pKa (~7.5), which actively redirects LNPs to the spleen instead of the liver. This precise spleen‑targeting property enables efficient transfection of splenic antigen‑presenting cells (APCs). As a vaccine adjuvant, AMG514‑LNPs therefore elicit a more robust activation of adaptive immunity compared to conventional LNPs (e.g., cKK‑E12), generating significantly enhanced antigen‑specific CD8⁺ T‑cell and antibody responses, and inducing durable anti‑tumor immune memory in preclinical models.

CICL1 (L829)​​ is a ​​novel ionizable cationic lipid​​ specifically engineered for ​​targeted lipid nanoparticles (tLNPs)​​ that enables efficient in vivo delivery of mRNA payloads to ​​CD8+ T cells​​. Designed to overcome limitations of conventional LNPs, CICL-1 (L-829)​​significantly ​​reduces off-target delivery to the liver​​ and exhibits ​​rapid clearance​​ compared to benchmark lipids like ALC-0315, while demonstrating ​​enhanced biodegradability and tolerability​​ in rodent and primate models. When incorporated into CD8-targeted tLNPs, CICL 1 (L829 enables ​​preferential transfection of CD8+ T cells​​ over other immune subsets, facilitating the generation of functional ​​anti-CD19 or anti-CD20 CAR T cells directly *in vivo​​*. These tLNP-engineered CAR T cells mediate ​​rapid, deep B-cell depletion​​ in humanized mice and cynomolgus monkeys, with repopulating B cells exhibiting a naïve phenotype suggestive of immune reset. By eliminating the need for ex vivo manufacturing or lymphodepleting chemotherapy, the L829-tLNP platform represents a ​​safer, scalable approach​​ for accessible CAR T therapy in oncology and autoimmune diseases.

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

DOTAP, also known as 1,2-Dioleoyl-3-trimethylammoniumpropane, is a cationic liposome-forming compound used for transfection of DNA, RNA, and other negatively charged molecules into eukaryotic cells. It has been used in gene delivery vectors for gene ther

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.

93-O17S is an imidazole-based synthetic lipidoid for in vivo mRNA delivery. Lipid nanoparticles (LNPs) with 93-O17S promotes both the cross-presentation of tumor antigens and the intracellular delivery of cGAMP (STING agonist).

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.

N-[1-(2,3-Dioleyloxy)propyl]-N,N,N-trimethylammonium (DOTMA) is a cationic lipid.It has been used as a component in liposomes that can be used to encapsulate siRNA, microRNAs, and oligonucleotides and for gene transfection in vitro.

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.

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.

DMA4-H228 is a novel, biodegradable lipidoid specifically engineered for spleen-targeted mRNA delivery.​​ Its structure combines a dimethylamino (DMA4) headgroup with a unique hyperbranched lipid tail (H228) synthesized via Michael addition, incorporating ester bonds for enhanced biodegradability. This design enables the formation of stable lipid nanoparticles (LNPs) (~170 nm) with high mRNA encapsulation efficiency (>96%). Critically, DMA4-H228 exhibits exceptional intrinsic tropism for the spleen (>98% targeting efficiency after IV administration), requiring no external targeting ligands. It selectively delivers mRNA to splenic antigen-presenting cells (APCs), including dendritic cells, macrophages, and B cells. This triggers potent immune activation: rapid IFNα secretion, upregulation of APC maturation markers (CD86/CD40), and robust antigen-specific immune responses. Demonstrating significant therapeutic potential, DMA4-H228-based mRNA vaccines effectively inhibit tumor growth in melanoma models (e.g., B16F10-OVA). This correlates with increased tumor-infiltrating CD8⁺ T cells, a shift towards pro-inflammatory M1 macrophages, elevated antigen-specific antibodies (IgG), and strong T cell responses (evidenced by IFNγ⁺ spots). Its ability to bypass liver tropism and directly activate splenic APCs makes DMA4-H228 a powerful platform for next-generation mRNA vaccines and cancer immunotherapy.

H5T5 is a leading ionizable lipid nanoparticle (LNP) formulation optimized for in vivomRNA delivery, featuring a pKa of 6.51, a size of ~154 nm, and a narrow polydispersity index (PDI) of 0.05. It demonstrated superior in vitromRNA transfection efficiency in primary immune cells, such as bone marrow-derived macrophages. Following intravenous administration, H5T5 exhibits precise organotropism, predominantly targeting the spleen and bone marrow, where it effectively delivers mRNA to a broad spectrum of immune cells, including macrophages, dendritic cells, T cells, B cells, and NK cells. This capability enables its core application: the in vivogeneration of "pan-CAR" immune cells. When loaded with anti-HER2 CAR mRNA, the H5T5-based therapy achieved potent tumor regression and prolonged survival in multiple solid tumor models. Preliminary safety assessments indicated a manageable cytokine profile and no significant organ toxicity, positioning it as a promising platform for in vivocell engineering.

Lipid 2306 is a novel ionizable lipid developed by Sail Biomedicine demonstrates excellent performance with a spleen-to-liver ratio of 3.68 and a very high total expression level of 2.5E+07. Lipid 2306 offers a strong balance of efficient systemic protein production and clear preferential delivery to the spleen.

Lipid 2310 is a novel ionizable lipid developed by Sail Biomedicine demonstrates excellent performance with a spleen-to-liver ratio of 5.58 and a very high total expression level of 1.3E+07. Lipid 2310 offers a strong balance of efficient systemic protein production and clear preferential delivery to the spleen.

CL15F6 is an ionizable cationic lipid (pKa = 6.75).1 It has been used in the formation of lipid nanoparticles (LNPs) for the delivery of mRNA and polymer-lipid hybrid nanoparticles for the delivery of plasmid DNA in vitro.1,2

Sail Lipid 2231 is a novel ionizable lipid targeting to spleen developed by Sai Biomedicine.As described on US20250205167A1 Lipid 2231 features a ​​pyrrolidine core​​ (5-membered ring) with biodegradable ester linkages and asymmetric C17/C11 hydrophobic chains. In vivo data shows moderate spleen targeting (Spleen RLU: ​​3.8E+06​​) with a spleen-to-liver ratio of ​​12.767​​.

Sail Lipid 2308​ is a novel ionizable lipid targeting to spleen developed by Sai Biomedicine.As described on US20250205167A1, Lipid 2308 was designed with a ​​piperidine core​​ (6-membered ring) and asymmetric C17/C11 chains, this lipid achieves unprecedented ​​spleen-specificity​​. It demonstrates dominant spleen accumulation (Spleen RLU: ​​7.8E+06​​, 91.8% of total signal) with a record ​​spleen-to-liver ratio of 112.7​​ (9× higher than 2231). Despite lower protein expression (hEPO: 11,000 ng/mL), near-zero liver uptake (Liver RLU: 66,000) makes Lipid 2308 unparalleled for vaccine/immunotherapy applications targeting splenic immune cells.

CL15F 6-4 is a short-tail ionizable lipid from the piperidine-based CL15F series, characterized by its symmetric branched structure with a 6-carbon main chain and 4-carbon side chain. This specific tail length critically determines the lipid nanoparticle's (LNP) properties, resulting in larger particles with a high surface density of the phospholipid DSPC. This elevated DSPC density reduces interactions with serum proteins like ApoE, minimizing rapid liver clearance and shifting mRNA delivery preference towards the spleen. Consequently, CL15F 6-4 LNPs achieve efficient, endogenous spleen-targeted delivery, making them a highly promising candidate for enhancing vaccine efficacy by preferentially transfecting antigen-presenting cells without complex functionalization.

A3B7C2 is an imidazole-containing ionizable lipid evaluated in a four-component LNP for spleen-selective reporter mRNA expression.

OF-C4-Deg-Lin is a novel ionizable lipid for RNA delivery.

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.

93-O17O is a chalcogen-containing ionizable cationic lipidoid. It has been used in the generation of lipid nanoparticles (LNPs). LNPs containing 93-O17O localize to the spleen after intravenous injection into mice.LNPs containing 93-O17O have been used for the delivery of Cre recombinase and ribonucleoproteins for genome editing in mice and for the intratumoral delivery of cGAMP to enhance cross-presentation of tumor antigens.

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.

A2T2C9 (CP-LC-1465) is an imidazole-based ionizable lipid with branched hydrophobic chains and β-propionate linkers, formulated in four-component LNPs for spleen-targeted mRNA delivery. It achieves >80% spleen selectivity with protein expression exceeding 1×10⁷ p/s in mice, driven by its negative zeta potential (-9.7 to -19 mV). Structural features including imidazole polar head and branched acrylate (C9) enhance splenic tropism, potentially through distinct protein corona interactions. Demonstrated low cytotoxicity (>75% viability in splenic cells) and biodegradability via pH-sensitive linkers enable efficient mRNA delivery without permanent charged additives, outperforming conventional anionic SORT systems in selectivity and therapeutic potential.

Lipid 11-A-M (LNP Lipid-8) is a specialized single-tail, multi-head ionizable cationic lipid engineered for targeted nucleic acid delivery to T cells. Unlike traditional lipids that exhibit strong liver tropism, 11-A-M formulations successfully bypass hepatocytes, resulting in negligible liver accumulation and toxicity. Upon intravenous administration, it naturally localizes to peripheral immune organs, enabling robust gene silencing and transfection specifically within splenic CD3⁺ T cells, with a higher efficiency in CD8⁺ cytotoxic T cells over CD4⁺ helper T cells. This liver-evading, T cell-specific targeting profile makes it a premier tool for in vivo immunotherapy and in situ cell reprogramming.

IAJD93(IAJD-93) is a pentaerythritol-based one-component ionizable amphiphilic Janus Dendrimer (IAJD), delivery systems for mRNA 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.

Lipid 29d is an ionizable lipid containing a thiophene moiety (Thio-lipid) for mRNA delivery. Lipid 29d enables LNPs to transfect the lung and spleen.

18-2-9b2 is a dendron-like degradable ionizable lipid which facilitates mRNA delivery to splenic macrophages. 18-2-9b2 LNP encapsulating therapeutic BTB domain and CNC homologue 1 (BACH1) mRNA exhibited proficient BACH1 expression and subsequent Spic downregulation in splenic red pulp macrophages (RPM) in a Spic-GFP transgene model.

2Ac3-C18 is a core-degradable ionizable lipid with two ester-linked branches, two tertiary amines and two C18 alkyl tails. Its four-component LNPs, formulated with DOPE, cholesterol and DMG-PEG2000, showed spleen-selective reporter-mRNA expression after intravenous administration in mice.

Lipid 2298 is a novel ionizable lipid developed by Sai Biomedicine demonstrates excellent performance with a spleen-to-liver ratio of 3.448​ and a very high total expression level of 2.4E+07. Lipid 2298 offers a strong balance of efficient systemic protein production and clear preferential delivery to the spleen.

113-AA-C8C14 is a spleen-tropic ionizable lipid with inherent splenic organ selectivity. Its formulated LNPs drastically reduce off-target liver uptake and drive 57-fold higher mRNA expression in spleen versus benchmark LNPs. It preferentially delivers nucleic acids to splenic immune cells like macrophages and T lymphocytes, supporting in vivo CAR-T engineering and mRNA vaccine research with minimal accumulation in other visceral organs.

Cl-4A3-LNSC8​ represents a novel class of thiourea-functionalized ionizable lipids engineered for selective organ-targeted mRNA delivery. Its core innovation lies in an anion-coordination strategy, where the parent lipid, 4A3-LNSC8, binds chloride ions (Cl⁻) via hydrogen-bonding interactions with its thiourea groups. This binding event is not merely structural but functionally critical, as it induces a significant shift in the surface pKa of the resulting lipid nanoparticles (LNPs) from approximately 5.54 to 8.79. This pKa modulation is the key mechanism that redirects the organotropism of the LNPs upon systemic administration. While the unmodified 4A3-LNSC8 LNPs preferentially deliver mRNA to the liver, Cl-4A3-LNSC8 LNPs effectivelyreprogram this tropism, enabling highly efficient mRNA delivery to secondary lymphoid organs (SLOs), particularly the spleen and lymph nodes. This platform demonstrates remarkable efficacy, achieving up to 65.7% gene editing efficiency in splenic macrophages in vivo, significantly outperforming benchmark delivery systems. Furthermore, by leveraging the coordination with different halides, such as iodine for computed tomography (CT) contrast, the system can be adapted for dual-modal theranostic applications, enabling simultaneous lymphatic metastasis imaging and therapeutic mRNA delivery.

OF-Deg-Lin is a biodegradable lipid containing an ester group, developed from the nonbiodegradable, linoleic acid derived OF-02; mRNA-LNPs containing OF-Deg-Lin showed high expression in the spleen.

IAJD 288(IAJD-288) is a pentaerythritol-based one-component ionizable amphiphilic Janus Dendrimer (IAJD), delivery systems for mRNA delivery.

TE-EP8-S is a single-component, ionizable cationic lipid designed specifically for the targeted delivery of mRNA to T cells within the spleen. This innovative lipid formulation enhances the efficiency and precision of mRNA-based therapies by ensuring optimal cellular uptake and expression in immune cells. Its unique structure and properties make it a promising tool for advancing immunotherapeutic applications.

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.

Si12-C10 is a siloxane-incorporated lipid for spleen-targeting mRNA delivery. The siloxane moieties enhance cellular internalization of mRNA-LNPs and improve their endosomal escape capacity, augmenting their mRNA delivery efficacy.

Lipid I97 is a vitamin B5-derived ionizable lipid for mRNA vaccine delivery. Lipid I97 LNP specifically delivers the mRNA to the spleen and lymph nodes in model mice, induces balanced Th1/Th2 immune responses, and elicits the production of high levels of neutralizing antibodies with low toxicity.

iChol15-C4A2 is a groundbreaking ionizable cholesteryl lipid, expertly designed to overcome the primary challenge of liver-centric accumulation in mRNA therapeutics. Its innovative "two-in-one" structure seamlessly integrates cholesterol with an ionizable headgroup, enabling the formation of stable, three-component Lipid Nanoparticles (Tc-LNPs).The key advantage of Tc-LNPs formulated with iChol15-CA2 is their significantly reduced adsorption of Apolipoprotein E (ApoE).This unique property directly attenuates ApoE/LDLR-mediated uptake by liver cells, dramatically shifting biodistribution toward extrahepatic tissues. Peer-validated research demonstrates a remarkable 20-50 fold increase in the spleen-to-liver mRNA expression ratio compared to standard LNPs like ALC-0315, unlocking unparalleled potential for targeting the immune system. Beyond its superior targeting capability, iChol15-C4A2 ensures high mRNA encapsulation efficiency, excellent colloidal stability, and proven biocompatibility. It offers a powerful, off-the-shelf solution to advance next-generation mRNA applications, from innovative vaccines and cancer immunotherapies to treatments for splenic disorders. Discover how iChol15-C4A2 can transform your delivery platform.

GL5 is an ionizable guanidine-based lipid nanoparticle (G-LNP) designed for superior mRNA delivery. Its guanidinocarbonyl-pyrrole (GCP) headgroup enables pH-responsive behavior and strong mRNA binding via bidentate hydrogen bonds. The cholesterol-free GL5-3 formulation forms compact, stable nanoparticles (~90-120 nm) that exhibit excellent spleen-targeting capability after intravenous injection.GL5-LNPs efficiently deliver mRNA to antigen-presenting cells (APCs), enhancing antigen presentation and T cell activation. In cancer immunotherapy models, GL5-based mRNA vaccines provided complete tumor protection and induced durable immune memory. The platform also enables mRNA delivery to other organs like the pancreas via different administration routes, demonstrating remarkable versatility and therapeutic potential.

​​L829​​ is a ​​novel ionizable cationic lipid​​ specifically engineered for ​​targeted lipid nanoparticles (tLNPs)​​ that enables efficient in vivo delivery of mRNA payloads to ​​CD8+ T cells​​. Designed to overcome limitations of conventional LNPs, L829 significantly ​​reduces off-target delivery to the liver​​ and exhibits ​​rapid clearance​​ compared to benchmark lipids like ALC-0315, while demonstrating ​​enhanced biodegradability and tolerability​​ in rodent and primate models. When incorporated into CD8-targeted tLNPs, L829 enables ​​preferential transfection of CD8+ T cells​​ over other immune subsets, facilitating the generation of functional ​​anti-CD19 or anti-CD20 CAR T cells directly *in vivo​​*. These tLNP-engineered CAR T cells mediate ​​rapid, deep B-cell depletion​​ in humanized mice and cynomolgus monkeys, with repopulating B cells exhibiting a naïve phenotype suggestive of immune reset. By eliminating the need for ex vivo manufacturing or lymphodepleting chemotherapy, the L829-tLNP platform represents a ​​safer, scalable approach​​ for accessible CAR T therapy in oncology and autoimmune diseases.