2Ac3-C18 is a unique ionizable lipid with a distinct degradable core structure：featuring 2 acrylate units and 3 amine groups—linked to a C18 alkyl chain. Its LNPs (formulated with DOPE/cholesterol/DMG-PEG2000) exhibit spleen-specific mRNA delivery in vivo.

Lipid te AA3-Dlin is a novel ionizable lipid developed for mRNA-LNP vaccines.When formulated into LNPs, te AA3-Dlin demonstrates excellent stability in serum and protects encapsulated mRNA from degradation. A key feature is its unique protein corona profile, with high ApoE abundance, which is crucial for efficient in vivo targeting, particularly to the spleen. This enables potent dendritic cell transfection, leading to enhanced antigen presentation and robust cytotoxic T-cell responses for superior antitumor immunity.

The PyCB (Pyridine Carboxybetaine) lipid 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.

Lipid A-12 is an ionizable cationic lipid from Capstan Therapeutics and a close analog of CICL-1 (L829). The key structural distinction is in the headgroup spacer length, where the value of 'n' is 1 in A-12, compared to 0 in CICL-1 (L829).

(4S)-KEL12​​ is a novel, biodegradable ionizable lipid developed for advanced mRNA vaccine delivery. It was rationally designed by incorporating both a ketal group in the linker and ester segments in the hydrophobic tails, a dual-degradable strategy aimed at enhancing its safety profile. Through iterative optimization, (4S)-KEL12 was identified as a lead candidate with an optimal pKa value of approximately 6.78, which is crucial for efficient mRNA encapsulation and endosomal release.

NC-TNP (noncationic thiourea lipids nanoparticles) could compress mRNA by strong hydrogen bonds interaction between thiourea groups of NC-TNP and the phosphate groups of mRNA. NC-TNP could escape the recycling pathway to inhibit the egress of internalized nanoparticles from the intracellular compartment to the extracellular milieu. NC-TNP-encapsulated mRNA shows higher gene transfection efficiency in vitro and in vivo than mRNA-LNP formulation. NC-TNP also shows spleen targeting delivery ability with higher accumulation ratio (spleen/liver), compared with traditional LNP.The C18 non-cationic thiourea lipid self-assembles into ~100 nm nanoparticles with neutral surface charge, utilizing strong hydrogen bonding between its thiourea groups and mRNA phosphate groups for efficient mRNA complexation. This delivery system demonstrates significantly enhanced EGFP expression efficiency—2.3-fold higher than standard C6/C12 formulations—in DC2.4, B16, and 4T1 cells, while sustaining luciferase activity for over 20 days post-subcutaneous injection. It exhibits exceptional stability, maintaining >94% mRNA integrity and <10% particle size variation after 30-day lyophilized storage. Importantly, the nanoparticles show pronounced spleen-targeting capability with 20-fold greater accumulation in the spleen versus liver, effectively activating twice the level of antigen-specific CD8⁺ T cells. Critically, the system avoids cationic lipid-associated toxicity, inducing no detectable IL-6/CXCL10 inflammation and causing no histopathological damage in cardiac or splenic tissues, thus establishing a novel high-efficacy, low-toxicity mRNA 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.

E12LA6B603（ILB3132，ILB-3132） is a novel ionizable amino lipid disclosed in patent WO2024198497A1, developed by MagicRNA, representing a highly efficient component for lipid nanoparticle (LNP) delivery systems.When formulated into LNPs, E12LA6B603 LNP achieves a remarkable 98.26% encapsulation efficiency for mRNA. It mediates superior in vitro transfection in dendritic cells (1.8E+05 intensity) and demonstrates best-in-class in vivo protein expression after intramuscular injection (2.2E+09 intensity). Most notably, in a B16-OVA melanoma model, therapeutic OVA-mRNA vaccines delivered by E12LA6B603 LNPs induced 100% complete tumor regression, highlighting its superior efficacy over benchmarks like DLin-MC3 and SM-102. Its biodegradable ester linkages and balanced structure make it a promising, potent candidate for next-generation mRNA vaccines and therapeutics.

​​Lipid 10a-26​​ is an ionizable lipid developed by Orna Therapeutics for lipid nanoparticle (LNP) formulations. It features a biodegradable ester backbone and an ionizable headgroup, enabling efficient encapsulation and delivery of circular RNA (oRNA). Experimental data show that Lipid 10a-26 mediates robust protein expression in hepatocytes and immune cells (e.g., T cells), with strong liver-targeting specificity observed in vivo. Its optimized hydrolysis profile ensures stable oRNA delivery and reduced immunogenicity. For instance, LNPs formulated with Lipid 10a-26 (molar ratio 50:10:38.5:1.5) demonstrate high transfection efficiency in splenic B cells and sustained therapeutic protein production.The lipid’s design balances efficacy and safety, making it ideal for applications like CAR-T therapy and hepatic protein replacement.

A5-CE-C7-6 is an ionizable lipid engineered for spleen-targeted mRNA delivery, integrating a hydroxylated dual-amine core (A5) for enhanced mRNA binding and endosomal escape, a biodegradable carbonate ester linker (CE) enabling rapid hydrolysis (61% degradation in 24 h), and branched heptyl hydrophobic tails (C7-6) that optimize nanoparticle stability and spleen tropism.​​ When formulated into cholesterol-free lipid nanoparticles (B-8 formulation), its unique architecture—combining hydroxyl groups for cellular uptake, carbonate-mediated biodegradability, and branched-chain fluidity—achieves unprecedented efficiency: low pKa (~6.0) minimizes liver accumulation while enabling ​​21% transfection of splenic NK cells​​, outperforming benchmark systems like MC3 SORT LNPs by >10-fold in spleen-specific delivery and establishing a new standard for in vivo immune cell engineering.

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.

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.

E10i-494 is a branched ionizable lipid designed to enhance the delivery of mRNA and CRISPR-Cas9 ribonucleoprotein (RNP) complexes. It belongs to the Branched Endosomal Disruptor (BEND) lipid family, which features terminal branching to improve endosomal escape and cellular uptake.E10i-494 demonstrated exceptional performance in T cell engineering, achieving >80% transfection efficiency in primary human T cells. This is significantly higher than the ~70% efficiency achieved by the linear lipid C14-494.The isopropyl branch enhances the lipid's ability to penetrate and disrupt endosomal membranes, leading to improved release of mRNA and RNPs into the cytoplasm.Despite its high efficiency, E10i-494 exhibits low cytotoxicity, making it suitable for therapeutic applications.E10i-494 is particularly effective for delivering mRNA to T cells, making it a promising tool for CAR-T cell therapy and other immunotherapies.Its ability to deliver CRISPR-Cas9 RNPs efficiently also makes it suitable for in vivo gene editing applications.

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.

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.

​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. 

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.

U-101 is an ionizable lipid for mRNA delivery. U101-LNP/IL-2F mRNA formulation demonstrats effective antitumor activity and safety.LNPs containing lipid U 101 and encapsulating mRNA encoding a fusion protein composed of IL-2, a linker, and CD25 inhibit tumor growth in an MC-38 mouse xenograft model.

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.

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.

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.

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.

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.

Lipid C14-A1 is an ionizable lipid. C14-A1-LPN is a potent and safe LNP platform to deliver Foxp3 mRNA to CD4+ T cells to engineer immunosuppressive FP3T cells.

9322-O16B is a lipidoid for the efficient delivery of antiCD19 mRNA CAR to murine primary macrophages. LNP 9322-O16B is more efficient than delivery with lipofectamine 2000 (LPF2K) or MC3.

113-O12B is a disulfide bond-containing ionizable cationic lipidoid. 113-O12B LNP, an LN-targeting LNP delivery system, is developed for a mRNA cancer vaccine. The 113-O12B/mRNA shows enhanced expression in APCs compared with ALC-0315/mRNA, indicating the LN-specific targeting ability.

OF-C4-Deg-Lin is a novel ionizable lipid for RNA delivery. OF-C4-Deg-Lin LNPs entrapping mRNA coding for luciferase induce the majority of protein expression in the spleen, with minimal translation in the liver, and negligible translation in other organs. OF-C4-Deg-Lin LNPs entrapping mRNA coding for luciferase induce the majority of protein expression in the spleen, with minimal translation in the liver, and negligible translation in other organs. To improve the mRNA delivery to extrahepatic tissues, a series of degradable diketopiperazine-based ionizable lipids were synthesized. Through evaluating the mRNA functional activity delivered by iLNPs, it was found that the ionizable lipids with doubly unsaturated lipid tails and linkers containing a length of four carbon aliphatic chain (Of-C4-Deg-Lin) could deliver the mRNA more efficiently. Moreover, compared with cKK-E12 and Invivofectamine, Of-C4-Deg-Lin could specifically induce more than 85% of firefly luciferase expression in spleen,minimal expression in the liver, and insignificant expression in other tissues.