(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.

H5T5 is a leading ionizable lipid nanoparticle (LNP) formulation optimized for in vivomRNA delivery, featuring a pKa of 6.51, a size of ~154 nm, and a narrow polydispersity index (PDI) of 0.05. It demonstrated superior in vitromRNA transfection efficiency in primary immune cells, such as bone marrow-derived macrophages. Following intravenous administration, H5T5 exhibits precise organotropism, predominantly targeting the spleen and bone marrow, where it effectively delivers mRNA to a broad spectrum of immune cells, including macrophages, dendritic cells, T cells, B cells, and NK cells. This capability enables its core application: the in vivogeneration of "pan-CAR" immune cells. When loaded with anti-HER2 CAR mRNA, the H5T5-based therapy achieved potent tumor regression and prolonged survival in multiple solid tumor models. Preliminary safety assessments indicated a manageable cytokine profile and no significant organ toxicity, positioning it as a promising platform for in vivocell engineering.

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.

A28-C6B2 is a biodegradable ionizable lipid specifically engineered for spleen-targeted delivery. Through its unique branched structure, it bypasses hepatic uptake to achieve highly efficient transfection of F4/80+ macrophages and CD11c+ dendritic cells within the spleen. This lipid remains neutral in the bloodstream to minimize non-specific interactions, while undergoing protonation in the acidic environment of the endosome to facilitate nucleic acid release, thereby significantly enhancing the potency of mRNA vaccines and immunotherapies.

Sail Lipid 2308​ is a novel ionizable lipid targeting to spleen developed by Sai Biomedicine.As described on US20250205167A1, Lipid 2308 was designed with a ​​piperidine core​​ (6-membered ring) and asymmetric C17/C11 chains, this lipid achieves unprecedented ​​spleen-specificity​​. It demonstrates dominant spleen accumulation (Spleen RLU: ​​7.8E+06​​, 91.8% of total signal) with a record ​​spleen-to-liver ratio of 112.7​​ (9× higher than 2231). Despite lower protein expression (hEPO: 11,000 ng/mL), near-zero liver uptake (Liver RLU: 66,000) makes Lipid 2308 unparalleled for vaccine/immunotherapy applications targeting splenic immune cells.

​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. 

Lipid 7669 is a premium, spleen-tropic ionizable lipid highly validated in US2025/0049948A1 for targeted mRNA delivery. Engineered for extrahepatic targeting, it achieves exceptional splenic protein expression while minimizing hepatic accumulation, significantly outperforming conventional liver-targeting lipids like MC3 and C12-200. In vivo bioluminescence data confirms its superior whole-body transfection efficiency and highly selective spleen tropism. This high-performance lipid is ideal for pioneering research in mRNA vaccines, splenic immune editing, and autoimmune disease therapies requiring precise extrahepatic delivery. Lipid 7669 is for research purpose.

C18 NC-TNP is a novel noncationic thiourea lipid without positively charged groups. It binds nucleic acids via hydrogen bonds instead of electrostatic attraction, avoiding cation-triggered systemic inflammation. Formulated into nanoparticles, it efficiently encapsulates mRNA, siRNA and plasmids, shows excellent serum tolerance and long-term liquid/lyophilized storage stability. It enters cells mainly through macropinocytosis, escapes endosomes intact to reduce nucleic acid degradation. In vivo, it targets spleen preferentially, induces robust long-lasting Th1-type cellular and humoral immunity with minimal organ toxicity, superior to SM102 LNPs for mRNA cancer vaccine delivery.

OF-Deg-Lin is a biodegradable lipid containing an ester group, developed from the nonbiodegradable, linoleic acid derived OF-02; mRNA-LNPs containing OF-Deg-Lin showed high expression in the spleen.

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.

TE AA3-Dlin is an optimized lipid nanoparticle (LNP) carrier designed for mRNA-based cancer immunotherapy, enabling precise in vivo dendritic cell (DC) reprogramming to enhance antitumor immunity. TE AA3-Dlin LNP exhibits superior serum stability, maintaining consistent particle size and low turbidity under physiological conditions, while protecting mRNA from degradation, which is crucial for effective delivery. Functionally, TE AA3-Dlin preferentially targets splenic DCs by leveraging ApoE-enriched protein coronas, facilitating efficient cellular uptake and mRNA expression, as demonstrated by enhanced EGFP signals in DCs.This targeting promotes DC maturation, antigen presentation, and membrane-bound IL-15 expression, activating cytotoxic T lymphocytes (CTLs) for tumor rejection. In models like melanoma and colon carcinoma, it synergizes with checkpoint inhibitors, showing minimal toxicity and robust immunological memory.

SAL12 is a novel ionizable lipid derivative that integrates a non-nucleotide STING agonist (agonist 6) with an amino lipid tail through an ester bond, forming the core component of specialized lipid nanoparticles (SAL12-LNPs). These nanoparticles are designed for dual functionality: they efficiently encapsulate and deliver mRNA into dendritic cells while concurrently activating the STING pathway to stimulate innate immunity.

​​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.

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.

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.

The AA15 lipid, an amino acid-derived ionizable lipid, integrates a carboxylic acid-containing headgroup and biodegradable branched ester tails (R2) to enhance mRNA delivery. Optimized as AA15V LNP, it exhibits a hydrodynamic diameter of 102.3 ± 4.1 nm, low polydispersity (PDI <0.15), and slightly positive zeta potential (+4–6 mV), enabling efficient tumor-targeted delivery. With a pKa ~6.1–6.4, AA15V ensures protonation in acidic endosomes, promoting mRNA release. It achieves >85% mRNA encapsulation efficiency, critical for stable saRNA delivery. In vitro, AA15V LNP-sSE-SCTs induced sustained SE-SCT expression (69% H-2Kb+β2m+ B16F10 cells at 72 h), outperforming mRNA formulations. In vivo, a single intratumoral dose of AA15V LNP-sSE-SCTs suppressed tumor growth by 22-fold in vaccinated mice, synergizing with checkpoint inhibitors (anti-PD-1/CTLA-4) for complete regression in 28.6% of lymphoma models. Ex vivo, AA15V enabled SE-SCT expression in human glioblastoma (7.1% CD45− cells) and lung cancer samples (5.8–8.7%), underscoring clinical potential. Key data: pKa ~6.3; encapsulation: 85–89%; zeta: +4–6 mV; size: 102.3 ± 4.1 nm. 

AA2 lipid is an innovative amino alcohol-derived ionizable lipid designed for optimized mRNA delivery. Its unique structure includes a hydroxyl-containing headgroup that enhances mRNA binding through hydrogen bonds and a branched ester tail (R2) that promotes a cone-shaped architecture, facilitating efficient endosomal escape. Formulated into lipid nanoparticles (LNPs) with a size of 108.6 ± 3.7 nm and a polydispersity index (PDI) below 0.3, AA2 achieves high mRNA encapsulation efficiency (89.0 ± 1.4%) and an ideal pKa of approximately 6.2, ensuring effective endosomal release.In vivo studies demonstrate that AA2 LNP-encapsulated spike mRNA elicits 4.7-fold higher IgG titers and robust CD8+ T-cell responses (characterized by IFN-γ+, TNF-α+, and granzyme B+ markers) compared to SM-102/ALC-0315 LNPs. Notably, AA2 exhibits minimal off-target accumulation, with low biodistribution in the liver and spleen. Its slightly positive surface charge (+3–5 mV) enhances cellular uptake, while the biodegradable ester structure ensures metabolic clearance, reducing potential toxicity.

ST12 is a lipid-conjugated DMXAA prodrug designed for temporally controlled STING activation in mRNA vaccine formulations. Its structure integrates a mouse-specific STING agonist, a biodegradable ester linker, an RNA-interacting tertiary amine domain, and two hydrophobic tails. When incorporated as a partial replacement for SM-102, ST12 preserves early antigen mRNA translation and subsequently releases DMXAA to activate STING. This delayed activation supports localized type I interferon signaling, enhanced antigen-specific CD8-positive T-cell responses, and improved antitumor immunity. In preclinical OVA and HPV tumor models, ST12-based Syn-STING vaccines suppressed tumor growth and prolonged survival. ST12 remains a preclinical research lipid developed specifically around DMXAA-sensitive STING systems.

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.

C12-2aN is a crosslinked ionizable lipid developed for mRNA vaccine delivery and dendritic-cell metabolic reprogramming. Its structure combines two piperazine-based ionizable amine cores, a bis-amidine crosslinker, and four hydroxylated C12 hydrophobic tails. When formulated with DOPE, cholesterol, and C14-PEG2000, C12-2aN LNPs enhanced mRNA endosomal escape and activated AMPK–mTORC2-dependent glycolysis, supporting dendritic-cell maturation and antigen presentation. In preclinical mouse studies, C12-2aN LNPs generated robust humoral and cellular immune responses in SARS-CoV-2 RBD and OVA cancer-vaccine models. The formulation also demonstrated reduced liver-associated off-target expression and lower acute inflammatory markers than the tested control formulations. C12-2aN is a preclinical research lipid intended for evaluating metabolically active mRNA vaccine delivery systems.

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