Yirui Li

BioE PhD Proposal Presentation

Date: Friday, Feb 21, 2020

Time: 2:00 pm

Location: MoSE 3201A

Advisor:

Julie Champion, Ph.D. (School of Chemical & Biomolecular Engineering, Georgia Institute of Technology)

Committee:

Shuichi Takayama, Ph.D. (Department of Biomedical Engineering, Georgia Institute of Technology)

Ravi Kane, Ph.D. (School of Chemical & Biomolecular Engineering, Georgia Institute of Technology)

Valeria Milam, Ph.D. (School of Materials Science and Engineering, Georgia Institute of Technology)

James Dahlman, Ph.D. (Department of Biomedical Engineering, Georgia Institute of Technology)

Engineering Recombinant Protein Vesicles for Delivery Applications

Recombinant proteins have emerged as promising building blocks for self-assembly of nanoparticle. Their versatility, accessible through genetic manipulation, and biocompatibility are key advantages compared with synthetic block copolymers. One example of recombinant protein materials is hollow vesicles self-assembled from recombinant fusion proteins containing thermoresponisve elastin like polypeptide (ELP). While synthetic nanoparticles typically require chemical conjugation or physical adsorption to incorporate biofunctional proteins, protein vesicles are made directly from biofunctional proteins. This prevents loss of protein structure and activity, and enables control over protein orientation. Vesicles use high affinity leucine zippers, ZE and ZR, to enable a range of different biofunctional proteins to be displayed on the surface at controlled density. The overall goal of this work is to translate protein vesicles into functional materials made from bioactive proteins with the required physical and biological properties for use as delivery vehicles.  For increased stability at physiological conditions, a photo-crosslinkable unnatural amino acid was incorporated into the ELP domain.  Vesicle size was reduced from micron scale to nano scale by tuning ionic strength and amino acid hydrophobicity. To demonstrate the potential as a modular platform for drug delivery and vaccine delivery, a HER2 targeting protein, DARPinG3, and model antigen protein, ovalbumin (OVA), will be fused ZE and incorporated into self-assembled vesicles. In addition to protein “cargo” assembled in the membrane, small molecule and nucleic acid cargos will be encapsulated in the vesicle lumen. Hydrophilic cargos, such as oligonucleotides, will require the ELP domain to be engineered to be charged during vesicle assembly. This work will be the first to make therapeutic protein vesicles, and will demonstrate the value of this platform in delivering a wide range of cargos with vastly different properties, ranging from small hydrophobic molecules, to nucleic acids and large, folded proteins