◥ Speaker:  Dr. Hyunmin Yi (Tufts University)

◥ Date:  23 Dec, 2016 (Fri) 11:00

◥ Place:  Seminar room 1 (#1101) @ W1-3 Bldg.

◥ Title: Nanobiofabrication: Exploiting Programmable Properties of Biological Materials and Interactions for Fabrication of Nanocatalysts and Biosensing Platforms

◥ Abstract:

 Controlled and programmable fabrication of functional materials at the nano to micro scales under mild aqueous conditions is an unmet challenge. Our approach to addressing these challenges is biofabrication, that is to understand and utilize the programmable functionalities of biologically derived materials and interactions. At the nanobiofabrication group of Tufts University, we exploit a range of toolsets from viral nanotemplates to polysaccharides in conjunction with robust soft-lithographic fabrication and bioorthogonal conjugation schemes. Viral assemblies have attracted substantial attention as templates for materials synthesis due to their precisely controlled dimensions, chemical functionalities and the ability to confer additional modalities through genetic modification.  We harness several unique properties of tobacco mosaic virus (TMV) for facile synthesis of catalytically active palladium (Pd) nanoparticles and fabrication of high capacity biosensing platforms.  In the nanocatalysis area, we have examined and demonstrated size-controlled synthesis, high thermal stability and TMV template’s fundamental role in the Pd nanoparticle formation via small angle X-ray Scattering (SAXS).  We then employed two Pd-catalyzed model reactions, dichromate reduction for environmental cleanup and Suzuki coupling reaction for efficient chemical synthesis, in order to investigate the catalytic activity, stability and reaction mechanisms.  The results show that the TMV-templated Pd nanoparticle synthesis offers attractive routes to highly active, controlled and stable catalyst systems in mild aqueous conditions.  In the biosensing area, we have enlisted TMV’s dual functionality coupled with robust micromolding techniques for controlled fabrication of high capacity biomolecular assembly platforms. First, genetically displayed cysteines allow for biomolecular conjugation via two high-yield bioorthogonal conjugation reactions.  Second, partial disassembly of TMV’s mRNA genome enables orientationally controlled assembly via nucleic acid hybridization.  Third, simple, clean and robust micromolding techniques lead to scalable fabrication of shape-controlled polymeric microparticles.  We envision that the seamless integration of these three traits in our approach would lead to promising fabrication schemes for high capacity biosensing platforms.  In this presentation, our recent progress on the fabrication of hybrid microparticles and microspheres with controlled macroporous structures and chemical functionality for improved protein conjugation in integrated fabrication-conjugation methods will also be highlighted.