(6gu) Programming Macromolecular Assemblies with Controlled Architecture and Size Towards Packaging and Delivery of Peptide-Based Therapeutics

My research professorship in biomedical engineering at Duke University (2014-present) and postdoctoral work (Harvard University, 2011-2014, 2 years 3 months) are connected by soft matter systems for materials science and engineering, specifically: (i) using high-throughput drop microfluidics for building complex polymeric micro-structures and (ii) programming the phase behavior and self-assembly of genetically engineered polypeptides into hierarchical architectures. My research focuses on developing an in vitro platform to resolve sequence-property relationships of proteins within the context of liquid-liquid phase behavior for encoding the stimulus-induced phase behavior of protein mixtures. I demonstrate the reversible formation of a variety of protein-rich architectures, ranging from uniform nano-, meso-, and micro-scale puncta (small, distinct particulates) to orthogonal, multilayered granules. This work focuses on proteins possessing sequences of low-complexity (SLC), as they are prototypical building blocks for the reconstitution of cell-free protein granule assays because of their compositional and structural similarity to the native proteins involved in cellular assemblies. My current interest is using this approach to engineer protein-based hydrogels for packaging of protein therapeutics and studying multilayer protein adsorption. In addition to this work, I have mentored and supervised undergraduates, graduates and postdocs on a number of multidisciplinary projects. Thus, I believe that my training and expertise position me advantageously for transition into a tenure track faculty position.

As a junior faculty member, my first aim is to take advantage of programmable self-assembly of macromolecules to systematically investigate and optimize engineered hierarchical nano- and micro-structures. I will initially study the structure-property relationship by investigating how subtle polypeptide sequence mutations direct phase behavior and surface energies to obtain quantitative structure-property correlation rules. Programming the hierarchical assembly of polymeric components provides scaling capabilities (e.g. production rate, size) not easily offered by existing droplet microfluidic approaches. I will demonstrate this scaling capability by the biomanufacturing of functional, hierarchical macromolecular assemblies in the meso- and nano-scale range. This unique suite of materials will consist of phase separated protein assemblies and synthetic polymeric structures, with architectures including core-shell, blended alloys, and Janus-like arrangements. Finally, I will engineer functionality into these hierarchical assemblies to form tunable materials with potential applications in drug delivery, drug discovery, and bioanalytics. 

My second aim addresses the challenges arising from extended controlled delivery of peptide-based therapeutics for disease treatment. This exciting class of pharmaceuticals is increasingly used for the treatment of a variety of diseases; however, their main drawbacks include short half-life, poor stability, proteolytic susceptibility and poorly controlled pharmacokinetic profiles. To address this challenge, I will program the self-assembly of ELP fusion peptide therapeutics to build smart-release, monodisperse protein nano- and microparticles containing hierarchical structure. My first case study will be to provide sustained and tunable release of glucagon-like peptide-1 (first in vitro and subsequently from sub-cutaneous depots) for treatment of type 2 diabetes. I will investigate controlled release of intact long-circulating GLP1-ELP fusions from the particle depot by (i) including protease recognition sites within the crosslinked matrix for controlled release, (ii) by engineering self-assembled multicomponent core-shell peptide microparticles for tunable release profiles and (iii) engineering stimulus-induced closed-loop delivery of peptide therapeutics. My hypothesis is that programming smart particle assemblies of GLP1 protein fusions with intrinsically disordered ELPs will enable (1) unprecedented low-dosage, extended release of GLP-1 fusions for in-vivo glucose control and (2) a clinically translatable protein-based platform adaptable for a host of pharmacokinetic profiles.