Comparison of Surface Modification Techniques on Polydimethylsiloxane to Prevent Protein Adsorption

Polydimethylsiloxane (PDMS) is commonly used in microchip fabrication due to its biocompatibility, which is essential for biological applications, as well as other properties, including transparency to visible light, controllable gas permeability, mechanical and heat stability, and elasticity. Despite these properties, adsorption of biomolecules remains a major limitation of PDMS in biochips. Methods to prevent sample adsorption have been reported, and herein we compare several surface engineering methods that do not incorporate plasma pretreatment. Three methods - Teflon coating, water-repellent spraying, and perfluorodecyltrichlorosilane (FDTS) blending - were compared by evaluating the amount of fluorescein-isothiocyanate- conjugated bovine serum albumin (FITC-BSA) adsorbed onto the biochips. FDTS-blended PDMS significantly inhibited protein adsorption and showed good oleophobicity, but provided the lowest visible light transmittance of all materials tested.