Master of Science in Biological and Agricultural Engineering (MSBAE)
Biological and Agricultural Engineering
This thesis characterizes parylene-C films with respect to biological micro-electro-mechanical system (BioMEMS) applications. BioMEMS devices have fueled the growth and research in the area of detecting, analyzing and identifying pathogens rapidly with precision in the bio-medical applications, thereby positively impacting millions of lives and made it extremely popular among researchers. These devices are fabricated using state-of-the-art techniques usually involving more than one material which typically has different biocompatibility and is not acceptable for various BioMEMS and biomedical applications; therefore, a special biocompatible coating is required. The parylene polymer is an example of such a coating as it is known for its biocompatibility (U.S. Pharmacopoeia (USP) Class VI) as well as possessing pinhole free surfaces with low penetrability which provide exceptional barriers to moistures and solvents. The vapor deposition process utilized for depositing parylene coating also provide conformable, uniform thickness throughout targeted sample even with high aspect ratio microstructures, and is compatible with both polymeric (e.g. PMMA, polycarbonate, etc.) and non-polymeric (e.g. nickel, silicon, etc.) substrates, as the samples are kept inside a room temperature (25° C) chamber where the final deposition step occurs. In this study, parylene coatings were characterized with respect to surface roughness, where roughness measurements show no significantly changes when parylene are deposited on “smoother” pristine PMMA (from ~Ra=2.66nm to ~Ra=2.85nm) and polycarbonate (from ~Ra=3.02nm to ~Ra=5.92nm) and reduces roughness of “rougher” surfaces (electroplated nickel from ~Ra=374nm to ~Ra=201nm). Parylene is also characterize with respect to surface energy by measuring contact angles, where pristine parylene surface (contact angle = ~89°) becomes more hydrophilic by treating it with oxygen plasma (contact angle = ~32°). Surface modification was used to control the number of live cells (HeLa) attaching on parylene, where O2 plasma was used to increase this by 2-folds and altering substrate roughness helped in minimizing the cells adhesion to parylene.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Nguyen, Quoc Phuc, "Characterization of biocompatible parylene-C coating for BioMEMS applications" (2011). LSU Master's Theses. 1478.