COLL 360 |
| Marian Kaholek1, Jinho Hyun2, Woo-Kjung Lee3, Ashutosh Chilkoti2, and Stefan Zauscher3. (1) Mechanical Engineering and Materials Science, Duke University, 144 Hudson Hall, Durham, NC 27708, (2) Department of Biomedical Engineering, Duke University, Box 90281, Durham, NC 27708, (3) Department of Mechanical Engineering and Materials Science, Duke University, 144 Hudson Hall, Box 90300, Durham, NC 27708 |
| Fabricating stimulus-responsive, “smart” polymeric and biomolecular structures on surfaces and the control of their architecture on the nanometer length scale is important for applications in biosensors, proteomic chips and nanofluidic devices. Here we present methods that we have developed that allow for molecular-level control in the fabrication of polymeric and biomolecular nanostructures. First we describes the fabrication and characterization of stimulus responsive elastin-like polypeptide (ELP) nanostructures grafted onto functionalized thiolates patterned onto gold surfaces with dip-pen nanolithography (DPN). ELPs undergo a reversible, hydrophilic-hydrophobic phase transition in response to external stimuli, such as a change in temperature or ionic strength. This phase transition behavior was exploited to reversibly immobilize a thioredoxin-ELP (Trx-ELP) fusion protein onto the ELP nanopattern above the lower critical solution temperature (LCST) demonstrating the potential for ELP nanoarrays in reusable lab-on-chip devices for protein purification or nanoscale analysis. Next we describe the molecular recognition mediated, step-wise fabrication of streptavidin nanopatterns. Nanopatterned streptavidin surfaces serve as universal templates for molecular recognition mediated protein immobilization. We show that “smart”, reversible protein nanopatterns can be created using iminobiotin as the molecular recognition partner. Finally we describe the fabrication of stimulus-responsive, poly(N-isopropylacrylamide) (pNIPAAM) brush nanopatterns in a “grafting-from” approach that combines scanning probe lithography with surface initiated polymerization using atom transfer radical polymerization (ATRP). We demonstrate the reversible, stimulus-responsive conformational height change of these nanopatterned polymer brushes by inverse transition cycling in water, and water-methanol mixtures (1:1, v:v). This nanofabrication approach is generic and can likely be extended to a wide range of vinyl monomers.
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“Smart” Polymers on Surfaces and Colloids
2:00 PM-5:20 PM, Tuesday, March 30, 2004 Marriott -- Grand Ballroom J, Oral
Division of Colloid and Surface Chemistry |