Application of surface plasmon resonance spectroscopy for adsorption studies of different types of components on poly(dimethylsiloxane)

• Surface plasmon resonance spectroscopy was used for adsorption studies on poly(dimethylsiloxane) (PDMS) surfaces.
• The technique can be used to monitor the kinetics of adsorption and desorption of different molecules.
• Large, water-soluble polymer-like materials like proteins generally irreversibly adsorb to PDMS.
• We propose that the extent of adsorption of the components on PDMS is related more to size than to hydrophobicity.

Surface plasmon resonance (SPR) spectroscopy is utilized to study in real-time and, by label-free means, the reversible and quasi-irreversible adsorption of small ionic or neutral molecules, pharmaceuticals, and proteins on poly(dimethylsiloxane) (PDMS) surfaces. The SPR sensor is covered with 0.2% (w/v) PDMS in octane. During the timescale of a typical lab-on-a-chip analysis or an electrophoretic separation, it was found that small neutral components containing a hydrophobic part do not adsorb or absorb onto PDMS, while larger, water-soluble polymer-like materials like proteins generally irreversibly adsorb to PDMS. The technique can be used to monitor the kinetics of adsorption and desorption of the molecules. For the non-specific adsorption of teicoplanin to PDMS, a Langmuir-like adsorption isotherm was obtained (Kd = 32 ± 2 μmol L−1).

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