A novel phage display platform, NNJA, was developed for targeted and cytosolic delivery. This innovative approach involves engineering a lysosomal cathepsin substrate into phage PIII, which displays a unique random sequence at its N-terminus. By selectively eliminating lysosomal-trapped peptide-phage, NNJA enables peptide-phage that escapes lysosomes to advance to the next round. Proof-of-concept studies demonstrated efficient cytosolic siRNA delivery by NNJA peptides, leading to significant gene silencing across various cell types. The NNJA platform offers a highly efficient discovery engine for targeted delivery to cytosol.

Antibody-conjugated lipid nanoparticles (LNPs) are developed to enhance targeted drug delivery. By coupling antibodies to LNPs, we aim to improve therapeutic efficacy and reduce off-target side effects through precise localization to target cells.

Intracellular protein delivery is challenging due to cellular barriers. We developed a novel bioconjugation method to introduce anionic groups onto proteins, enhancing their encapsulation in lipid nanoparticles. This approach enables efficient intracellular protein delivery with potential for broad therapeutic applications.

Lentiviral vectors (LV) are powerful tools for cell and gene therapies. We have developed a direct reverse transcription digital droplet PCR (RT-ddPCR) approach without RNA extraction and purification for estimation of LV titer and genome integrity. The advantage of direct RT-ddPCR is to avoid the RNA extraction and handling. Our results showed that direct RT-ddPCR resulted in the equivalent titers determined by RNA extraction followed by RT-ddPCR.

We investigated the size limitations for molecules diffusing through a porous protein capsid. By encapsulating enzymes and varying the size of substrates, we determined the effective pore size and identified factors influencing molecular transport across the capsid.

Reverse micelle (RM) encapsulation has long been an attractive mechanism for biological delivery, yet an RM-based platform has yet to show generalized success for biocompatible encapsulation and delivery of drugs. We use RMs to encapsulate proteins for structure/function study. Recently, we have worked to leverage what works well for structural studies toward development of a biocompatible platform for protein encapsulation and delivery. Our most recent developments will be presented.

Development of AAV vectors with defined tissue tropism usually employs capsid engineering, often by inserting targeting peptides into capsid loops. However, engineered capsids with unique tissue tropism often show poor physicochemical properties that raise concerns in transduction efficiency, manufacturability, and safety. I will introduce a new method we have developed recently that can grant receptor-specific tissue tropism to natural and unmodified AAV9 capsids. This technology was used to achieve enhanced brain delivery of AAV9 in mice.