4A3-SC8

Literature evidence · DC82001

Formulation & Performance

The 2022 phospholipid study holds 4A3-SC8, cholesterol and DMG-PEG2000 constant while changing the phospholipid. The DOPE formulation below is one defined study variant, not a universal recipe for every experiment involving this lipid.

4A3-SC8 is distinct from 4A3-SC7 and 4A3-SCC-10. Evidence from those other lipids is not assigned to DC82001.

Formulation components and molecular-weight conversion

Component	DC Chemicals product	Molecular weight	Molar ratio	Mass at 1 µmol total lipid (mg)
4A3-SC8	DC82001	1467.2	38.5	0.564872
Cholesterol	DCD-041	386.65	30	0.115995
DOPE	DC33634	744.03	30	0.223209
DMG-PEG2000	DC40169	2507	1.5	0.037605

Study DOPE variant: 4A3-SC8/cholesterol/DOPE/DMG-PEG2000 = 38.5:30:30:1.5 mol%. The phospholipid was varied in parallel groups. Reported 4A3-SC8:mRNA mass ratio = 23:1; this is not total lipid:mRNA or N/P.

Component mass calculator

Prefilled proportions follow the source specified above. Molecular weights and ratios are editable. Results are calculated, not measured study data. No N/P or RNA dose is inferred.

Total lipid (µmol)

Component	Mass (mg)	Mass %
4A3-SC8	—	—
Cholesterol	—	—
DOPE	—	—
DMG-PEG2000	—	—

DSPC comparator in the phospholipid screen

Component	DC Chemicals product	Molecular weight	Molar ratio	Mass at 1 µmol total lipid (mg)
4A3-SC8	DC82001	1467.2	38.5	0.564872
Cholesterol	DCD-041	386.65	30	0.115995
DSPC	DC57005	790.15	30	0.237045
DMG-PEG2000	DC40169	2507	1.5	0.037605

Same fixed molar proportions, with DSPC replacing DOPE. The biological findings show that this substitution changes performance; equivalent delivery is not assumed.

Component mass calculator

Prefilled proportions follow the source specified above. Molecular weights and ratios are editable. Results are calculated, not measured study data. No N/P or RNA dose is inferred.

Total lipid (µmol)

Component	Mass (mg)	Mass %
4A3-SC8	—	—
Cholesterol	—	—
DSPC	—	—
DMG-PEG2000	—	—

Particle properties across the phospholipid screen

Study / condition	Result	Interpretation
Four-component variants	Approximately 100 nm; PDI <0.2; zeta potential about −2 to −4 mV	Screen-level characterization, not a batch release specification.
RNA encapsulation	>80% for most variants; cardiolipin variant approximately 50%	The cardiolipin result is not assigned to DOPE LNPs.
Storage observations	Physical characteristics followed over 72 h at room temperature and 4°C	This is not a long-term shelf-life validation.

Main Results and Supplementary Figs. S1–S2 as described by the authors. Complete SI retrieval remains pending.

Cellular mRNA delivery

Study / condition	Result	Interpretation
HEK293T and HeLa cell studies	PE-headgroup phospholipids supported higher reporter expression than the tested PC-containing comparators	Phospholipid chemistry was the experimental variable.
Uptake versus expression	Differences in uptake did not fully explain reporter expression	Internalization alone is an incomplete delivery endpoint.
DOPE versus DSPC imaging	Lower lysosomal colocalization for the DOPE formulation	Supports improved intracellular release in this comparison.

Main Figs. 2–3; comparisons remain specific to the tested cells and formulations.

Membrane-interaction evidence

Study / condition	Result	Interpretation
Endosomal-mimic liposomes	PE-containing formulations showed greater lipid fusion	Cell-free mechanistic assay.
DOPE and DSPC formulations	Fusion and intracellular localization supported the delivery ranking	Not a direct quantitative measurement of in vivo endosomal escape.
Generalization	Helper-lipid identity can alter productive delivery with the same ionizable lipid	No claim that every PE phospholipid is optimal for every RNA or tissue.

Main Fig. 4 and associated discussion.

Mouse organ expression and SORT context

Study / condition	Result	Interpretation
Female C57BL/6; 0.03 mg luciferase mRNA/kg IV; 6 h; n = 3	DOPE-, POPE- and 4ME-containing LNPs gave liver-predominant expression	Reporter protein expression, not an RNA biodistribution measurement.
BMP phospholipid variant	Spleen-predominant expression	Lower total expression than leading PE formulations does not negate organ selectivity.
Separate five-component SORT experiment	20% and 30% BMP produced spleen-selective delivery; 20% was the strongest tested setting	Different formulation series from the 38.5:30:30:1.5 screen.
SORT composition boundary	Results state a 15:15:30:3 base; Methods contains an extra ratio term	No prefilled SORT recipe is supplied until the SI table resolves the discrepancy.

Main Figs. 5–6. The malformed Methods ratio is not silently treated as a validated formulation.

Additional study and limits of evidence

Study / condition	Result	Interpretation
2020 theranostic study	4A3-SC8 with a PEGylated BODIPY co-component supported reporter delivery and tumor imaging	Different PEG component and formulation; no DMG-based recipe is inferred.
Tumor imaging versus treatment	Reporter expression and near-infrared imaging were measured	These endpoints do not demonstrate antitumor efficacy.
Safety scope	No comprehensive repeat-dose toxicity margin established by the 2022 phospholipid study	Do not import safety results from 4A3-SC7 or other related lipids.

Álvarez-Benedicto et al. (2022); Xiong et al. (2020).

Original study figures

Cellular localization and membrane fusion — Figures 3–4 — Original source figures.

Organ expression and SORT comparison — Figures 5–6 — Original source figures.