Therapeutic LNP Engineering

Lipid nanoparticles (LNPs) have rapidly transformed the field of RNA therapeutics by providing a safe and efficient means of delivering RNA molecules into target cells. Their proven success in mRNA vaccines and other applications has made LNPs the gold standard for RNA delivery in both research and clinical settings. At VectorBuilder, we are committed to driving innovation to support researchers and developers with high-performing LNP solutions for each stage in the development pipeline.

Highlights

Formulation Engineering

Standard and custom LNP formulations optimized for maximum stability, delivery efficiency, and expression levels.

Antibody Conjugation

Full antibody or fragment conjugation, with site-specific options available to enhance tissue targeting and delivery precision.

Top-Quality Production

High-performance LNPs with up to 100% encapsulation efficiency and <0.1 polydispersity index for superior homogeneity.

Seamless Integration

Fully integrated with VectorBuilder’s end-to-end LNP-RNA platform from vector design to GMP manufacturing.

Choose VectorBuilder’s innovative LNP platform to deliver your RNA’s full potential.

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Technical Information

LNP Service Overview

LNPs are tiny spherical particles typically ranging from 10 to 1000 nanometers in diameter. They are increasingly used for various applications including translational research, mRNA vaccines, and drug delivery. With therapeutic molecules (e.g. oligonucleotides) encapsulated within the core, the outer shell of LNPs is made of different types of lipids, each having different functions to support the stability, structure, and delivery efficiency of LNP-based drugs (Figure 1).

Ionizable cationic lipids, such as DLin or SM-102, facilitate nucleic acid encapsulation and promote endosomal membrane disruption, enabling efficient release of nucleic acids into the cytoplasm while maintaining low cytotoxicity.

Sterol lipids, such as cholesterols, improve structural rigidity, thereby reducing leakage from the particle core.

Oligonucleotides, such as RNA or DNA plasmids, are encapsulated within the aqueous core.

Stealth lipids, such as PEGylated lipids, help maintain the particle size and stability via the hydrophilic steric barrier formed by PEG chains at the surface. The presence of PEGylated lipids also reduces clearance by the monocytic phagocyte system.

Glycerophospholipids, such as DSPC, DODMA, or DOPE, modulate the net charge of the particles and can enhance cellular delivery.

Figure 1. The typical structure of an LNP-based drug delivery system.

Despite their success in mRNA vaccines against SARS-CoV-2 infection and other promising applications, LNP-based drug delivery still faces challenges including the inherent immunogenicity of LNPs, their limited ability to target specific tissues, and the difficulty of restricting expression exclusively to the intended tissues. To address these issues, VectorBuilder has established a comprehensive LNP platform that enables highly homogeneous (polydispersity index <0.1) and efficient (up to 100%) encapsulation of therapeutic RNA or DNA molecules. We specialize in optimizing LNP compositions and formulations, as well as conjugating antibodies or other targeting ligands to the LNP surface for enhanced biocompatibility, tissue specificity, delivery efficiency, and overall therapeutic efficacy.

LNP Formulation Engineering

VectorBuilder offers both standard (e.g. SM102, ALC-0315, MC3) and custom LNP formulations. Our proprietary novel formulations are designed to enhance transfection and expression efficiency both in vitro and in vivo. In addition, we can help you optimize or modify existing formulations to improve delivery efficiency, increase RNA expression, address immunogenicity concerns, and achieve optimal performance of your LNP therapeutics.

Antibody-Conjugated LNPs

At VectorBuilder, we can perform antibody conjugation using the following methods:

Thiol-maleimide reaction

F(ab’)2 conjugation

Site-specific antibody conjugation using modified N-glycans

Site-specific antibody conjugation using engineered scFv

Antibody fragment (e.g. F(ab')2 or scFv) or site-specific conjugation offers several advantages over full antibody or random conjugation, as summarized in the table below:

Category	Feature	Comparison
Antibody Type	Antibody fragment vs. full antibody	Smaller size of antibody fragment allows for higher conjugation efficiency, loading capacities and oriented arrangement on the LNP surface. Antibody-fragment-conjugated LNPs have lower immunogenicity compared to full antibody conjugation due to lack of Fc region. The use of antibody fragments enables deeper tissue penetration and more targeted delivery of RNA into dense tissues.
Conjugation Method	Site-specific vs. random conjugation	Site-specific conjugation provides better control over stoichiometry, as random conjugation can occur at multiple primary amine sites on antibodies. Site-specific conjugation avoids steric hindrance by controlling the orientation of conjugated molecules, whereas in random conjugation the orientation is uncontrolled because primary amines are generally positioned randomly within the targeting ligand.

If you wish to develop custom antibodies for optimal tissue specificity and precise delivery of RNA therapeutics, VectorBuilder can help you with our proprietary high-throughput antibody discovery services.

Case Studies

Formulation Engineering

Antibody Conjugation

VectorBuilder’s extensive experience in LNP formulation optimization helps improve the performance of RNA therapeutics.

Figure 2. LNP formulations achieve efficient plasmid transfection in vitro. (A) A plasmid overexpressing EGFP (pDNA-CMV>EGFP) was encapsulated with SM102 or ALC-0315 LNP and transfected to HEK293T cells. The EGFP expression was captured 24 h post-transfection. (B) Optimized SM102-based LNP formulation achieved ~6.6 times better transfection to HEK293T cells than a commercial PEI transfection reagent. A firefly luciferase expressing plasmid (pDNA-CMV>Fluc) was used as the reporter.

Figure 3. Novel LNP formulation developed by VectorBuilder enables long-lasting in vivo expression. A Luciferase-expressing plasmid (pDNA-CAG>Luc+) was encapsulated within the novel LNPs, which was subsequently intravenously injected at 0.6 mg/kg body weight. Luciferase expression was detected up to 96 h post-injection.

Figure 4. Optimized LNP formulation enables highly efficient transfection in primary human T cells. (A) Activated T cells were transfected with LNP-encapsulated EGFP mRNA at 6 ug mRNA per 1×10⁶ cells. (B) Denaturing agarose gel electrophoresis confirmed the correct length and integrity of the EGFP mRNA before encapsulation. (C) The particle size and Zeta potential of the LNPs were measured before T cell transfection. (D) EGFP expression was imaged and analyzed 24 hours post-transfection using fluorescence microscopy and flow cytometry.

Figure 5. A novel LNP composition significantly reduces in vivo immunogenicity. In this formulation, PEGylated lipids were replaced with polysarcosine (pSar) lipids for M1ψ-incorporated HiExpress™ FLuc LNP-mRNA. Alongside the PEG-lipid formulation, both LNP-RNAs were injected intravenously, and FLuc expression was imaged 6 hours post-injection. Two proinflammatory cytokines in the serum were then quantified by ELISA 24 hours post-injection.

Figure 6. The GalNac-modified LNP enables liver-specific targeting. (A) Characterization of GalNAc and SM102 lipid nanoparticles by dynamic light scattering (Zetasizer). (B) Efficient hepatic delivery of mRNA in C57BL/6 Ldlr^−/− mice using a GalNAc-LNP. HiExpress™ Firefly Luciferase IVT mRNA made with m1Ψ was encapsulated with GalNAc or standard SM102-based LNP. Each wild-type or Ldlr knockout mouse was intravenously administered via tail vein with 0.5 mg encapsulated RNA per kg of body weight. Luciferase activity was visualized by live imaging at 6 h and 24 h post-injection.

VectorBuilder’s antibody conjugation expertise enables precise targeting and optimal delivery of RNA therapeutics.

Figure 7. Anti-CD31 conjugated FLuc LNP-mRNA improves luciferase expression in the lung. Mouse strain: C57BL/6J; age: 6-8 weeks; gender: female; administration route: intravenous tail vein injection. Negative controls: IgG2a-conjugated FLuc LNP-mRNA.

Figure 8. Tissue-specific mRNA delivery using antibody-conjugated LNP. (A) Ai9 mice harboring a cre-dependent tdTomato expression cassette were intravenous injected with Cre mRNA encapsulated in LNP conjugated with or without anti-CD31 antibodies (0.4 mg/kg). (B) tdTomato expression in the lung was visualized 72 h post injection.

Figure 9. Enhanced lung targeting achieved with full antibody and F(ab’)2 conjugation. Fluc LNP-mRNA was conjugated either with anti-CD31 full antibody or F(ab’)2 and administered via intravenous injection in mice (n=3).

Figure 10. Enhanced lung targeting achieved with site-specific antibody conjugation. Fluc LNP-mRNA was site-specifically conjugated with anti-CD31 full antibody or scFv and administered via intravenous injection in mice.