Serum protein layers on parylene-C and silicon oxide: effect on cell adhesion.

Among the range of materials used in bioengineering, parylene-C has been used in combination with silicon oxide and in presence of the serum proteins, in cell patterning. However, the structural properties of adsorbed serum proteins on these substrates still remain elusive. In this study, we use an optical biosensing technique to decipher the properties of fibronectin (Fn) and serum albumin adsorbed on parylene-C and silicon oxide substrates.

Optical extinction combined with phase measurements for probing DNA-small-molecule interactions using an evanescent waveguide biosensor.

We demonstrate the use of both optical extinction and phase measurements for probing the interactions between DNA and small molecules by dual polarization interferometry. On binding to DNA at the interface, mitoxantrone (MTX) and methylene blue (MB) induced reversible concentration-dependent optical extinction due to light absorption, which clearly revealed the association and dissociation of small molecules with DNA in real time. The binding constants of MTX-DNA and MB-DNA determined from the masses derived from optical extinction are 1.

Multiple path length dual polarization interferometry.

An optical sensor for quantitative analysis of ultrathin films and adsorbed layers is described. Quantification of both layer thickness and refractive index (density) can be made for in situ and ex-situ coated films. With the use of two polarizations, in situ measurements are made via one path length in a young's interferometer arrangement while ex-situ measurements use multiple path lengths.