Iso-A11B5C1 is an ionizable lipid. The iso-A11B5C1 LNP demonstrates a high level of muscle-specific mRNA delivery efficiency. exhibiting transfection efficiency comparable to the commercially available lipid SM-102, while considerably reducing inadvertent mRNA expression in main organs such as the liver and spleen.Additionally, study results show that intramuscular administration of mRNA formulated with iso-A11B5C1 LNP caused potent cellular immune responses, even with limited expression observed in lymph nodes.

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.

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.

503O13 is a next-generation, biodegradable lipid nanoparticle (LNP) engineered for highly efficient and targeted siRNA delivery. Designed through rational structure-activity criteria—including optimal tail length (O13), tertiary amines, and a surface pKa ≥5.5—this single-component LNP achieves unparalleled gene silencing with an ultra-low EC50 of 0.01 mg/kg in preclinical models.503O13 outperforms non-degradable counterparts (e.g., C12-200) with improved toxicity profiles—no hepatic necrosis or pancreatic inflammation—while maintaining rapid blood clearance (t1/2: 6 min) and organ-specific accumulation (liver/spleen).

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.

Lipid S4 is an advanced ionizable lipid engineered for systemic mRNA delivery to the brain, leveraging SR-57227—a high-affinity 5-HT3 receptor ligand—as its core head group to enable targeted blood-brain barrier (BBB) penetration via receptor-mediated transcytosis, while incorporating amino linkers for pH-responsive ionization and biodegradable branched ester tails to facilitate efficient endosomal escape and intracellular mRNA release; optimized through orthogonal screening into OS4 LNP (formulated at S4/DOPE/Chol/DMG-PEG2k = 40:40:60:0.75 molar ratio), it demonstrated a 13.3-fold increase in brain mRNA expression compared to FDA-approved MC3 LNPs, and further conjugation with the Tat cell-penetrating peptide yielded OS4T LNP, boosting delivery efficiency by 12.7-fold over OS4 alone and enabling broad mRNA expression across neurons, astrocytes, microglia, and endothelial cells; validated in orthotopic glioblastoma models, OS4T delivered engineered IL-12 mRNA, suppressing tumor growth and extending median survival to 37 days (vs. 17 days for controls) with minimal systemic toxicity, positioning S4-based LNPs as a robust, translatable platform for CNS-targeted therapeutics.

MK-16(pKa 6.86) is a specialized lipid designed to traverse the blood-brain barrier (BBB) for effective mRNA delivery. Its formulation, MK 16 BLNP, leverages dual mechanisms involving caveolae and γ-secretase to facilitate BBB penetration, ensuring the targeted and efficient transport of functional mRNA to diverse brain cell types. Demonstrating excellent tolerability across a range of dosing regimens, MK16 BLNP represents a promising platform for brain-targeted therapeutic applications.

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.

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.

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.

SM-86 Analog-1 is a novel ionizable lipid designed to improve the delivery of RNA via lipid nanoparticles (LNPs) It is derived from SM-86,with 8 carbon within its hydrophobic tail.

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.

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.​

ADA (Acid-Degradable Anionic Lipids) is revolutionizing mRNA delivery with its unique azido-acetal linker, enabling rapid hydrolysis in endosomes (pH ~6.0). This breakthrough technology ensures efficient endosomal escape, significantly enhancing mRNA delivery to target cells. ADA-LNPs excel in delivering mRNA to the spleen and liver, making them ideal for immune-related therapies.By degrading into biocompatible byproducts, ADA minimizes long-term tissue persistence and toxicity.ADA-LNPs outperform traditional LNPs, delivering mRNA more effectively to immune cells like macrophages and B cells.

Acid-degradable Cationic Lipid (ADC) composed of cationic lipid is synthesized with the azido-acetal linker and used to generate RD-LNPs, which significantly improves the performance of LNP-mRNA complexes in vitro and 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.

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.

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.

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.

A1-EP10-O18A​​ is an ​​asymmetric ionizable lipid​​ developed by Starna Therapeutics for mRNA vaccine delivery. Synthesized via Michael addition between amine alcohols and acrylates, its optimized structure—combining a hydrophilic C10 chain and hydrophobic unsaturated C18 tail—enables pH-dependent ionization. As the core component of the ​​STAR0225 lipid nanoparticle (LNP)​​ platform, it efficiently encapsulates mRNA and facilitates endosomal escape. Preclinical studies demonstrate superior in vivo mRNA delivery (vs. commercial SM102 LNPs), with enhanced local biodistribution and minimal off-target accumulation. This lipid underpins ​​STR-V003​​, an RSV prefusion F mRNA vaccine showing robust immunogenicity and protection in animal models, supporting its clinical transition (NCT06344975).

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.

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.

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