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.

ALC-0315 analogue-2 is an analogue of ALC-0315. ALC-0315 is an ionisable aminolipid that is responsible for mRNA compaction and aids mRNA cellular delivery and its cytoplasmic release through suspected endosomal destabilization. ALC-0315 can be used to form lipid nanoparticle (LNP) delivery vehicles. Lipid-Nanoparticles have been used in the research of mRNA COVID-19 vaccine.

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.

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.

Lipid88​​ is a high-performance, novel ionizable lipid component engineered for advanced mRNA-LNP vaccine delivery. LNP88 formulation demonstrates superior biodistribution, achieving >10-fold higher transfection efficiency in spleen and lymph nodes compared to benchmark lipids like ALC-0315 via intramuscular delivery. When encapsulating antigen-encoding mRNA (e.g., optimized mCSA construct), Lipid-88 based LNPs drive robust humoral and cellular immunity, enabling complete protection against challenging SARS-CoV-2 variants (WA1/2020, Omicron BA.1, BQ.1) in preclinical models. Its design prioritizes potent immunogenicity with favorable safety profiles.

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.

​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. 

A12-Iso5-2DC18 is a novel amine containing lipid can be used for mRNA delivery, activate the stimulator of interferon genes (STING) pathway, and exhibit anti-tumor immunity.

A18-Iso5-2DC18 that could not only deliver mRNA vaccines robustly but also activate the stimulator of interferon genes (STING) pathway.

A2-Iso5-2DC18 is a top-performing lipid for mRNA delivery in bone marrow-derived dendritic cells (BMDCs), BMDMs and HeLa cells.

​​DM3-BTA-14​​ is a cationic lipid compound engineered for high-efficiency mRNA delivery developed by Hefei AlphaNA Biotechnology. Its structure features a rigid benzene-1,3,5-tricarboxamide core linked to a protonatable dimethylamino headgroup (-N(CH₃)₂) via a propylene spacer (-CH₂CH₂CH₂-) and two saturated C14 alkyl chains. This design enables ≈90% endosomal escape efficiency , superior lymph node targeting for vaccines , and effective tumor-specific mRNA delivery . It outperforms benchmark lipids while maintaining low cytotoxicity, forming stable nanoparticles with cholesterol/DSPC/DSPE-PEG (50:39:10:1 ratio) for therapeutic applications.

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

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

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.

TS-202 is a novel ionizable lipid for RNA delivery.

SM86 is a cationic, ionizable lipid developed by Moderna as a core component of its lipid nanoparticle (LNP) platform for mRNA therapeutic delivery.SM-086 is structurally optimized and analogous to SM-102 (used in Moderna’s COVID-19 vaccines), with modifications aimed at enhancing mRNA delivery efficiency and safety.SM-86 serves as the primary cationic lipid in three investigational mRNA therapies targeting rare metabolic disorders:mRNA-3927: Restores propionyl-CoA carboxylase activity in propionic acidemia (PA). mRNA-3705: Delivers methylmalonyl-CoA mutase mRNA for methylmalonic acidemia (MMA). mRNA-3210: Provides phenylalanine hydroxylase mRNA to treat phenylketonuria (PKU).

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.

YK-009 is an advanced, biodegradable ionizable lipid designed for efficient mRNA delivery. Via intramuscular injection, it demonstrates superior targeting to draining lymph nodes, boosting immune cell transfection for vaccines. When administered intravenously, it distributes to the liver but leverages a highly degradable chemical backbone to ensure rapid clearance post-endosomal escape. This effectively eliminates the risk of long-term tissue accumulation and liver toxicity seen in traditional lipids. Delivering a balance of high transfection efficiency and exceptional biocompatibility, YK-009 is an ideal component for safe and potent lipid nanoparticle (LNP) formulations.

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.​

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 29 is an ionizable amino lipid (pKa = 6.91) from Moderna platform that has been used in combination with other lipids in the formation of lipid nanoparticles (LNPs).Administration of human erythropoietin (EPO) mRNA in lipid 29-containing LNPs increases serum EPO levels in mice.

Lipid B3 is a biodegradable ionizable lipid for liver targeted delivery. Lipid B3-LNP shows high delivery efficacy and low toxicity in delivering RNA to liver cells.

H7T4-4 is an ionizable lipid designed for mRNA delivery via lipid nanoparticles (LNPs). It features a cyclic amine headgroup (derived from cyclen tetrahydrochloride) and four C14 hydrophobic alkyl tails, synthesized through a Michael addition reaction between cyclen and 1,2-epoxytetradecane. With a high transition temperature (Tm = 58.6°C) due to strong intermolecular interactions from its cyclic headgroup and multi-tail structure, H7T4-4 alone forms rigid aggregates incompatible with mRNA encapsulation. However, when blended with low-Tm helper lipids (e.g., DOPE, Tm = -16°C), the system’s overall Tm decreases, enabling stable LNP formation. Optimized formulations (20% H7T4-4, 41% DOPE, 38% cholesterol, 1% DMG-PEG) exhibit efficient mRNA encapsulation (>90%) and transfection. Structural analyses (SAXS, cryo-TEM) confirm monodisperse LNPs with lamellar/hexagonal phases. In vivo, H7T4-4 LNPs show tumor-targeted and intranasal mRNA delivery with reduced off-target accumulation compared to SM-102-based LNPs. This rational design highlights Tm-guided helper lipid selection to overcome rigidity challenges in ionizable lipids.

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.

NT1-O12B, an endogenous chemical and a neurotransmitter-derived lipidoid (NT-lipidoid), is an effective carrier for enhanced brain delivery of several blood-brain barrier (BBB)-impermeable cargos. Doping NT1-O12B into BBB-impermeable lipid nanoparticles (LNPs) gives the LNPs the ability to cross the BBB. NT-lipidoids formulation not only facilitate cargo crossing of the BBB, but also delivery of the cargo into neuronal cells for functional gene silencing or gene recombination.

NT1-O14B is a tryptamine-containing cationic lipidoid.1 It has been used in combination with other lipids in the formation of lipid nanoparticles (LNPs). Intravenous administration of LNPs containing NT1-O14B and encapsulating antisense nucleotides against tau decreases tau brain levels in mice.

Lipid C12-A1 is an ionizable lipid. C12-A1-LPN is a potent and safe LNP platform to deliver Foxp3 mRNA to CD4+ T cells to engineer immunosuppressive FP3T cells. C12-A1 has a slightly lower average cell viability than C14-A1.

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.

503O8,12​​ is an ionizable lipidoid synthesized via Michael addition, combining a hydrophilic amine headgroup ("503" series) with two hydrophobic branched acrylate tails (C8 and C12 chains, likely with unsaturated bonds). Its design emphasizes organ-specific delivery, exhibiting ​​spleen-tropic targeting​​ in vivo.

C14-4 (C14-494,Lipid B-4,Lipid B4) is a novel ionizable lipid with the highest T-cell transfection efficiency and low cytotoxicity.The C14-4 ionizable lipid has been explored for CAR-T therapy.To screen the excellent formulations for mRNA delivery, a lipid library of 24 ionizable lipids was constructed to make iLNPs, which were used to deliver luciferase mRNA into Jurkat cells.[115] The optimal iLNPs formulation was C14-4 iLNPs (C14-4 ionizable lipid, DOPE, chol, and PEG at a molar ratio of 35%, 16%, 46.5%, and 2.5%) (Figure 6c). The optimal dose of luciferase mRNA for C14-4 iLNPs was 30 ng. Compared with electroporated CAR T cells, the CAR T cells engineered via C14-4 iLNPs showed potent cancer-killing activity when they were cocultured with Nalm-6 acute lymphoblastic leukemia cells. To obtain a safer and more effective CAR mRNA delivery vehicle, the orthogonal design provided 256 potential formulations, and 16 representative iLNPs formulations were evaluated.Through evaluating the safety, delivery efficiency, and transfection efficiency of 16 iLNPs, the formulation B10 (C14-4 ionizable lipid, DOPE, chol, PEG at a molar ratio of 40%, 30%, 25%, and 2.5%) was screened out as the optimal performing formulation. The luciferase expression based on B10 formulation was increased threefold than the initial formulation. Reducing the accumulation and clearance of iLNPs in the liver can increase the expression of CAR mRNA in T cells, further improving the therapeutic effect of CAR-T. Studies have shown that cholesterol analogs can alter the mechanisms of intracellular circulation and enhance the delivery of mRNA, which may be related to the reduced recognition of iLNPs by the Niemann Pick C1 (NPC1) enzyme.The addition of a hydroxyl group to various locations in the cholesterol molecule can alter the binding kinetics between the modified cholesterol and NPC1, and reduced NPC1 recognition of cholesterol. The results showed that replacement of 25% and 50% 7 α-hydroxycholesterol for cholesterol in iLNPs improved mRNA delivery to primary human T cells in vitro by 1.8-fold and twofold, respectively.C14-4 is one of the ionizable lipids to efficiently deliver mRNA to Jurkat cells or primary human T cells. It will effectively promote the development of mRNA delivery by iLNPs for CAR-T therapy.