514O6,10 is an ionizable lipidoid. 514O6,10 formulated LNPs facilitate mRNA delivery to the pancreas.

Si5-N14 is a lipid-based molecule engineered with siloxane groups, designed specifically for efficient mRNA delivery to the lungs. The incorporation of siloxane units boosts the cellular uptake of mRNA-loaded lipid nanoparticles (LNPs) and enhances their ability to escape from endosomes. These properties significantly increase the overall effectiveness of mRNA delivery, making Si5-N14 a promising tool for targeted therapeutic applications.

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.

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.

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.

DLin-KC3-DMA, a nucleic acid, shows in vivo silencing activity. DLin-K-C3-DMA can be used in the synthesis of nucleic acid-lipid particle to delivery of nucleic acid.

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.

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).

L-369 (Lipid 369,L369) is novel class of ionizable lipid for siRNA delivery with improved in vivo elimination profile with excellent translation across species,including NHP, wide safety margin.

C24 is a novel multiprotic ionizable lipid. C24 lipid nanoparticle (LNP) has a multistage protonation behavior resulting in greater endosomal protonation and greater translation compared to the standard reference MC3 LNP. C24 LNP also lower injection site inflammation and higher stability compared to MC3 LNP.

306Oi10 is a branched-chain ionizable lipidoid that has shown significant promise in the generation of lipid nanoparticles (LNPs) for mRNA delivery. Its unique structural and functional properties make it a highly efficient delivery vehicle for mRNA-based therapeutics.

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.

TNT-b10 is a novel Lipid-like compound suitable for delivery of siRNA and mRNA both in vitro and in vivo TNT-b10 LLNs was more than 10-fold more potent than TNT-a10 LLNs formulated under the same condition.

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.

Lipid 331 is a biodegradable cyclic ionizable lipid. LNPs containing Lipid 331 result in robust transfection in the nasal and lung tissues of mice and efficient transfection of lung epithelial cells and lung-resident APCs. Lipid 331 is a promising candidate for mRNA vaccine delivery, offering the potential for further enhancing the potency of mRNA vaccines.

L202 is an ionizable lipid designed for mRNA vaccines, featuring a pH-responsive N-methylpiperidine head and a unique branched-tail structure with ester linkages to enable biodegradability. With a pKa of ~6.04–6.29, it facilitates efficient endosomal escape while maintaining stability in physiological conditions. Formulated into lipid nanoparticles (LNPs) of ~103 nm (PDI 0.08), L202 achieves >97% mRNA encapsulation efficiency. Its optimized structure drives robust immunogenicity: in mice, a single 0.1–10 μg dose induced dose-dependent SARS-CoV-2 spike-specific IgG titers, outperforming MC3-based LNPs and protein-alum vaccines. L202-LNPs elicited balanced Th1/Th2 responses (IgG2a/IgG1 ratio) and potent germinal center B cell activation, critical for durable immunity. Lyophilization with 16% sucrose preserved mRNA integrity and immunogenicity after 1-month storage at 5°C or 25°C, addressing cold-chain limitations. In nonhuman primates, two 100-μg doses generated neutralizing antibody titers exceeding convalescent human sera, with broad efficacy against Alpha, Beta, Gamma, and Delta variants. Rapid tissue clearance (72 hours post-injection) and minimal hepatic accumulation, attributed to ester hydrolysis, enhanced safety profiles. Additionally, L202-LNPs functioned as intrinsic adjuvants, amplifying protein vaccine responses. Combined with its lyophilization compatibility, potent cross-variant immunity, and favorable pharmacokinetics, L202 represents a promising platform for next-generation mRNA 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.

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.

LIPID 14 is a novel ionizable lipid used for mRNA delivery.In 2021, Elia et al. used lipid 2 LNPs and lipid 14 LNPs to deliver mRNA encoding SARSCoV-2 human Fc-conjugated receptor binding domain (RBDhFc mRNA). While both lipid 274 LNP RBD-hFc mRNA and lipid 14 LNP RBD-hFc mRNA induced equal cellular and humoral responses in mice at an mRNA dose of 5 μg, only lipid 14 LNP RBD-hFc mRNA exhibited strong immunogenicity following intradermal administration. Both intradermal administration and intramuscular administration of lipid 14 LNPs could activate antigen presenting cells (APCs), thus inducing cellular responses.

A18-Iso5-2DC18 that could not only deliver mRNA vaccines robustly but also activate the stimulator of interferon genes (STING) pathway. A18-Iso5-2DC18 strongly binds to the stimulator of interferon genes (STING) and induces potent cytolytic T lymphocyte responses, resulting in substantial antitumor immunity (Miao et al. 2019).

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).

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.

306-O12B is a cationic lipidoid.306-O12B LNP is more efficient than MC-3 LNP in inducing loss-of-function mutations in Angptl3 through CRISPR-Cas9-based genome editing. It has been used in the generation of lipid nanoparticles (LNPs). Intravenous administration of LNPs containing 306-O12B and encapsulating an mRNA reporter accumulate specifically in the mouse liver. LNPs containing 306-O12B and encapsulating mRNA encoding the Cas9 nuclease (mCas9) and single-guide RNA targeting Angptl3 (sgAngptl3), the gene encoding angiopoietin-related protein 3, have been used to induce CRISPR-mediated gene knockdown in mice resulting in a reduction of serum Angptl3 protein, LDL, and triglyceride levels. A novel ionizable lipids library was constructed by a combinatory solvent-free Michael addition reaction between disulfide bondincorporated acrylate lipid tails and amine-containing heads. In this library, the tail-branched bioreducible ionizable lipid 306-O12B was screened out. Due to the presence of special ester bonds and branches in lipid tails, the accumulation of iLNPs in the liver was increased, and endosome escape was prompted. These iLNPs were used to deliver CRISPR-Cas9 mRNA and sgRNA targeting to angiopoietin-like 3 (Angptl3). Compared with FDA-approved MC3, 306-O12B induced more specific and efficient Angptl3 gene knockout in the liver, resulting in significant decrease in the levels of serum Angptl3 protein, low-density lipoprotein cholesterol (LDL-C), and triglyceride. According to the molecular shape hypothesis outlined several decades ago, the increase of branches can create ionizable lipids with more cone-shaped structure to enhance the destructiveness of the membrane structure of the endosome and increase mRNA release. However, it is unknown whether the structural stability of iLNPs will be sacrificed with the increase of branches. The optimal branches and chain length need to be further explored.

113-O16B is a disulfide bond-containing ionizable cationic lipidoid. It has been used in the generation of lipid nanoparticles (LNPs) for the delivery of mRNA.

LIPID-10a-26 is an analogue of ALC-0315 with the head adjusted to imidazole. It is a novel cationic ionizable Lipid for RNA delivery.

80-O16B is a disulfide bond-containing ionizable cationic lipidoid. It has been used in the generation of lipid nanoparticles (LNPs) for the delivery of CRISPR complementary single-guide RNA (sgRNA) and Cas9 for genome editing in mice. LNPs containing 80-O16B conjugated to phenylboronic acid (PBA) and encapsulating an mRNA reporter increase luciferase reporter expression in HeLa cancer cells.2 LNPs containing 80-O16B conjugated to PBA and encapsulating p53 mRNA decrease the viability of DU145 prostate and SiHa and HeLa cervical cancer cells.

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.

AA3-DLin is an ionizable cationic amino lipid (pKa = 5.8) that has been used in combination with other lipids in the formation of lipid nanoparticles (LNPs) for the delivery of mRNA.LNPs containing AA3-DLin and encapsulating mRNA for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein induce immunogenicity in mice.

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.

ALC-0315 analogous-1 is a derivative of the ionizable cationic amino lipid ALC-0315. It has been used in the synthesis of ionizable cationic lipids used in the generation of lipid nanoparticles (LNPs).