Design of a biocompatible surface by self assembly method

In this study, self assembled monolayers and multilayers were prepared by using 3-glycidoxypropyldimethylmethoxysilane(MAES), 3-glycidoxypropyldimethoxymethylsilane (DAES) and bis (3-aminopropyl) terminated poly(dimethylsiloxane) (PDMS), respectively. It was determined that MAES was self assembled as a monolayer while DAES was self assembled as a multilayer on silicon surface. At the second step, PDMS was covalently attached to the prepared epoxy terminated surfaces. Surface analysis of the prepared surfaces was done by atomik force microscopy (AFM), ellipsometry, Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy and contact angle measurements. The C1s and N1s peaks in the XPS spectrum indicated that MAES, DAES, MAES-PDMS, DAES-PDMS covalently attached to the silicon surface. Avarage thickness of MAES, DAES and polymeric layers on these surfaces was 0.8 nm, 2.9 nm, 4.8 nm, 5.4 nm, respectively. The water contact angle of MAES, DAES, MAES-PDMS, DAES-PDMS monolayer and multilayers was determined to be as 600, 430, 730 and 620 respectively. AFM analysis showed that each surface had different surface topography and RMS value. Furthermore, protein adsorption studies were carried out by amino terminated surfaces. The interactions between antigen and antibody on the prepared surfaces were also observed by using fluorescein labeled anti-hIgG. The differences of fluoresans images were detected by Fluoresans Microscopy. The prepared amino terminated surfaces may be used for DNA, cell, enzyme immobilization as well as antigen/antibody interaction.