Estimation of Biocompatibility of Polymeric Materials without Living Cells

Attenuated total reflectance (ATR) near infrared (NIR) and middle infrared (MIR) spectroscopes, which have the ability to observe the water-solid interface selectively, were constructed. Using ATR-NIR, a combination band (7000 cm-1) of OH symmetric and asymmetric stretching of water on hydrophilic (silanol) and hydrophobic (alkylated) solid surfaces was obtained. The ATR-NIR spectra indicated that the density of water on both the hydrophilic and hydrophobic surfaces increased in the range of 100 nm from the surface. Using ATR-MIR, amide I (1650 cm-1) and amide II (1550 cm-1) bands of the protein adsorbed on the surface were obtained. Structural change of the adsorbed protein on the hydrophobic surface was faster than that on the hydrophilic surface. A good correlation between the water structures and the structural changes of an adsorbed protein on the hydrophilic / hydrophobic surfaces was not observed.