Surface Modification of Confined Microgeometries via Vapor-Deposited Polymer Coatings

Abstract

The development of generally applicable protocols for the surface modification of complex substrates has emerged as one of the key challenges in biotechnology. The use of vapor-deposited polymer coatings may provide an appealing alternative to the currently employed arsenal of surface modification methods consisting mainly of wet-chemical approaches. Herein, we demonstrate the usefulness of chemical vapor deposition polymerization for surface modification in confined microgeometries with both nonfunctionalized and functionalized poly(p-xylylenes). For a diverse group of polymer coatings, homogeneous surface coverage of different microgeometries featuring aspect ratios as high as 37 has been demonstrated based on optical microscopy and imaging X-ray photoelectron spectroscopy. In addition, height profiles of deposited polymer footprints were obtained by atomic force microscopy and imaging ellipsometry indicating continuous transport and deposition throughout the entire microchannels. Finally, the ability of reactive coatings to support chemical binding of biological ligands, when deposited in previously assembled microchannels, is demonstrated, verifying the usefulness of the CVD coatings for applications in micro/nanofluidics, where surface modifications with stable and designable biointerfaces are essential. The fact that reactive coatings can be deposited within confined microenvironments exhibits an important step toward new device architectures with potential relevance to bioanalytical, medical, or "BioMEMS" applications.

Biomimetic Materials by Freeze Casting

“…A variety of different polymer infiltration techniques includes polymer melt immersion, 23 polymersolvent evaporation, [24][25][26][27][28] in situ polymerization, [19][20][21][29][30][31][32] particle centrifugation, 33 and chemical vapor deposition. [34][35][36] In situ polymerization is the most popular method used to impregnate porous scaffolds with polymers. In this method, a liquid monomer and catalyst are forced into the pores of a ceramic scaffold under vacuum and subsequently polymerized.…”

Electrophoretic separation of neurotransmitters on a polystyrene nano-sphere/polystyrene sulphonate coated poly(dimethylsiloxane) microchannel

“…Series of chemical or physical methods including graft polymerization, plasma treatment, UV/ozone treatment, silanization, adsorption of detergents, proteins, and polyelectrolytes have been used to modify the PDMS microchannel to meet the requirements in various applications. [11][12][13][14][15][16][17] For example, Wang et al 12 have layer-by-layer modified the PDMS microchannel with a straight-chain polymer (polyethyleneimine) and gold nanoparticles; Sui et al 13 performed an in situ polyethylene glyco (PEG) modified surface on pre-oxidized PDMS microchannel and then incubated with 2-[methoxy(polyethylenoxy)propyl] trimethoxysilane for 2-3 days to obtained a more hydrophilic PDMS surface with 40 of contact angle. Polystyrene (PS) microsphere is widely used as the modifier for chromatographic column.…”

Thin film diffusion barrier formation in PDMS microcavities

“…Chemical vapor deposition is a useful technique which provides reactive chemicals in the gas phase for surface reaction. Various strategies have been reported for functionalized and non-functionalized surface polymerization in microfluidic devices [12][13][14].…”