Patterning Interfaces with High Molecular Weight Periodically Sequenced Sheet-Forming Polypeptides

Cuny City College, New York NY

Investigators

Abstract

ID: MPS/DMR/BMAT(7623) 1006407 PI: Tu, Raymond ORG: CUNY City College Title: Patterning Interfaces with High Molecular Weight Periodically Sequenced Sheet-Forming Polypeptides INTELLECTUAL MERIT: The goal of the proposed work is to create a periodically sequenced polypeptide with a high molecular weight and a low polydispersity for patterning self-organized nanostructures confined at interfaces. Previous efforts in the PI's group to template interfaces with low molecular weight periodically sequenced peptides have yielded surface confined self-organized fibrillar patterns, but these patterns have a low aspect ratio and a high defect frequency. It is proposed here to use a condensation reaction to promote a high molecular weight periodically sequenced polypeptide (PSP). Typically, the polydispersity of the condensation polymerization process is determined by the statistics of recombination, leading to a broad distribution. The approach proposed for making these polypeptides with a high molecular weight and a narrow polydispersity is based on controlling the condensation kinetics of a growing beta-strand in a multiphase transport-limited reaction. The mechanism to synthesize a pseudo-living condensation polymer with narrow distribution is an outcome of three key phenomena: cooperative folding, Langmuir adsorption kinetics, and effective reaction rates that decrease as a function of molecular weight. To characterize the reaction products the PI will apply a combination of composition gradient-multi-angle light scattering, NMR, and LC-MS. To characterize assembly at the molecular length scale, Langmuir-Blodgett techniques, circular dichroism, and attenuated total reflectance-FTIR will be applied. Brewster angle microscopy, imaging ellipsometry, and fluorescent microscopy will be used to characterize assembly at the supramolecular length scale. BROADER IMPACTS: The proposal may lead to new, less expensive methodology for producing polypeptides of controlled sequence and chain length. It will support the work two graduate students and several undergraduate students. In fact, two undergraduate students conducted all the preliminary experiments upon which the proposal is built. Undergraduates will continue to participate through three distinct mechanisms. First, the PI participates in two NSF sponsored undergraduate education programs (1) NSF-NUE (Nanomaterials Education for Engineering and Science Majors at CCNY) (NSF EEC 0634223) and (2) NYU-CCNY, REU for the Science and Engineering of Soft Materials and Interfaces (NSF DMR 0648788). The NUE is designed to enhance nanotechnology and nanomaterials education for undergraduate students at CCNY. The REU is in collaboration with NYU, and the interdisciplinary focus is soft materials and interfaces. These outreach programs will expose students, who typically don't have opportunities in science and engineering, to academic research. Second, the PI aspires to provide quality undergraduate training to a highly diverse student body at CCNY (36% Hispanic, 30% black, 23% Asian and 11% white) through direct participation in his laboratory. Among the twenty students who have worked in the PI's lab eleven are women, including two Hispanic women and two African American women. The PI is dedicated to the development of a diverse laboratory environment, which is in accord with the CCNY mission. Third, the PI is integrating research and education in a comprehensive fashion from the graduate to the high school level. To this end, the PI is leading a Peer-Learning Program with the High School of Math, Science and Engineering (HSMSE) in Harlem, NY. The program has two goals: first, to excite and recruit students from a diverse community into STEM fields and, second, to engage more engineering students in teaching. The program propagates knowledge by giving undergraduate students at CCNY an opportunity to teach chemical engineering at HSMSE. Peer interactions foster a positive learning environment where interest in science and engineering is promoted through shared everyday experience. This notion of common ground is particularly important because the diverse population at HSMSE currently mirrors the makeup at CCNY.