Nicholas A. Peppas, Sc.D.

	James Zachary Hilt Graduate Student The University of Texas at Austin 1 University Station, MC C0400 Chemical Engineering Dept. Austin, TX 78712 PHONE: (512) 471-3477 FAX: (512) 471-3477 zach@che.utexas.edu

Research Summary
My research has focused on developing intelligent polymer networks for application in micro- and nanoscale devices, especially for biological and medical applications. In this research, two intelligent polymer network systems, which exhibit many similar properties however have distinct sensing/recognition capabilities and response characteristics, have been designed and fundamentally studied, environmentally responsive hydrogels and biomimetic recognitive networks. The applicability of environmentally responsive hydrogels as sensing elements that will actuate in response to an environmental condition, such as pH or temperature, has been analyzed. The actuation is driven by water up-take and expulsion from the network, which makes this a unique sensing/actuating element for microdevices. For the development of an innovative microsensor platform, these responsive hydrogels were integrated with a microcantilever transducer, which is able to detect surface stress changes with ultrasensitivity. Novel biomimetic recognitive networks that are entirely synthetic and tailored to have various recognition properties and function have been developed by analyzing protein binding domains and then designing polymer networks to mimic their molecular architecture. The relative binding affinity and selectivity was defined with precise control via the molecular design of the polymer network. Specifically, supramolecular interactions, such as hydrogen bonding and hydrophilic/hydrophobic interactions, were utilized to enable reversible binding/recognition of the target analyte. These biomimetic recognitive networks have been integrated with silicon microdevices as robust recognition elements for microsensors, microarrays, and other microdevice applications. In addition, a micro-reactor photolithography technique was developed to enable micropatterning of the intelligent polymer networks with precise spatial and thickness control. This novel technique, which utilizes a mask aligner to enable precise micropatterning via UV free-radical polymerization, was instrumental for the integration of the above mentioned intelligent polymer networks into silicon microdevices.

Selected Publications
J.Z. Hilt and M.E. Byrne. Configurational Biomimesis in Drug Delivery: Molecular Imprinting of Biologically Significant Molecules, Advanced Drug Delivery Reviews, in press. J.Z. Hilt, M.E. Byrne, “Biomedical Applications: Tissue Engineering, Therapeutic Devices, and Diagnostic Systems” In: J.A. Schwarz, C. Contescu, K. Putyera, eds., Dekker Encyclopedia of Nanoscience and Nanotechnology, 247 – 261, 2004. J.Z. Hilt, M.E. Byrne, and N.A. Peppas. Novel Biomimetic Polymer Networks: Development and Applicatoin as Selective Recognition Elements for Biomolecules at the Micro-/Nanoscale. AIChE Nanoscale Science and Engineering Topical Conference Proceedings, in press. [PDF File] J.Z. Hilt, A.K. Gupta, R. Bashir, and N.A. Peppas. Ultrasensitive bioMEMS sensors based on microcantilevers patterned with environmentally responsive hydrogels. Biomedical Microdevices, 3, 177-184, 2003. [PDF File] M.E. Byrne, E. Oral, J.Z. Hilt, and N.A. Peppas. Networks for recognition of biomolecules: molecular imprinting and micropatterning poly(ethylene glycol)-containing films. Polymers for Advanced Technologies, 13, 798-816, 2002. [PDF File] R. Bashir, J.Z. Hilt, O. Elibol, A. Gupta, and N.A. Peppas. Micromechanical cantilever as an ultrasensitive pH microsensor. Applied Physics Letters, 81, 3091-3093, 2002. [PDF File] J.Z. Hilt, A.K. Gupta, R. Bashir, and N.A. Peppas. A microsensor based on a microcantilever patterned with an environmentally sensitive hydrogel. In: Lee LP, Borenstein JT, Manginell RP, Okandan M, Hesketh PJ, eds., BioMEMS and Bionanotechnology, 173-178, MRS, Pittsburgh, PA, 2002.

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