(571g) Embedding Crystallographically Imprinted Surface Topographies in Micro- and Nano-Scale Fluidic Channels

Han, D. - Presenter, Texas A&M University
Ugaz, V., Texas A&M University

We describe a novel method to imprint complex surface topographies on biodegradable substrates by exploiting the sensitivity of enzymatic activity to a substrate’s degree of cyrstallinity. This process is illustrated in an enzyme/substrate system involving proteinase K and poly(lactic acid) (PLA), where a strong etch rate selectivity to PLA crystallinity is observed. By establishing a laminar flow of the enzyme solution through a template microchannel, morphological features associated with the substrate’s crystalline domains can be embedded into the sidewalls. The PLA crystalline morphology is governed by its thermal history (annealing time and temperature, cooling rate) and material properties (molecular weight), enabling the size and density of the imprinted features to be manipulated. We identify conditions under which post-like arrays of tunable size can be produced, making it possible to embed a variety of complex architectures within a micro- or nano-scale fluidic channels in a lithography-free manner. The simplicity and robustness of this approach may offer advantages for producing barrier or packing structures relevant for filtration and chromatography applications. The highly-specific nature of the governing interactions and wide range of enzyme/substrate combinations lays a foundation for broad control over the templated nano-scale morphologies.