Transforming Conventional Materials viaRational Design and Controlled Synthesis

I will cover three separate topics in my presentation to highlight research conducted in my group between 2011 and 2014. I will first present the development of charged, helical polypeptides and their applications in gene delivery, bacterial inhibition and cell membrane penetration. We successfully transformed the conventional polypeptides to highly useful materials with exceptional biological membrane activities that can undergo direct membrane pore formation in energy-independent manner. I will also present rational design of helix-to-coil and coil-to-helix transitions of polypeptides and their applications in unpackaging DNA, lowering intracellular toxicity and inhibiting bacterial at extreme pH. For the second topic, I will discuss the transformation of conventional silica nanoparticles to advanced nanomedicines. Specifically, I will present the design and synthesis of size precisely controlled silica nanoconjugates and their applications as drug delivery nanomedicine, and discuss the use of these size controlled silica nanoconjugates in various fundamental studies, such as cellular uptake, biodistribution, tumor tissue penetration and inhibition. I will then cover the third topic in the last part of my presentation and discuss our recent efforts on transforming conventional urea-based polymeric materials to functional polymers. Specifically, I will present the design of hindered urea bonds and the dynamic chemistry associated with these bonds. Using the reversible, dynamic hindered urea bonds, we successfully developed polymers capable of catalyst-free dynamic property change and autonomous repairing at low temperature. I will also briefly discuss the use of polymers containing hindered urea bonds as biomaterials for controlled release and drug delivery applications.