ADSORPTION OF FIBRINOGEN ON POLYIONIC AZOBENZENE LAYER-BY-LAYER FILM USING PHOTOISOMERIZATION

A number of surface sensitive analytical tools such as ellipsometry, surface plasmon resonance spectroscopy, quartz crystal microbalance and atomic force microscopy have been utilized. 5- 7 Fibrinogen is a plasma protein found in the circulatory system and is a common blood protein which plays a vital role in the formation of blood clots that can result in strokes. The protein is an elongated molecule that is 46 nm long, has a mass of 340 kDa and is found in blood at 2.60 mg mL -1 In this study, the adsorption of fibrinogen on an azobenzene containing ultrathin film was studied. Photoisomerization was done to better understand the effect of the cis/trans configurations with adsorption rate and surface properties. Quartz Crystal Microbalance (QCM) was used to observe the kinetics and measure the adsorption properties of the fibrinogen. The adsorption of protein on a layer-by-layer (LbL) film was studied using a QCM with photoirradiation. A photoactive azobenzene group was photoisomerized from trans- to cis-conformation in order to investigate the change in protein adsorption properties. By utilizing the LbL adsorption technique we have deposited multiple layers of polyionic films containing a photoactive azobenzene group onto solid substrates. Alternating layers of a polycation) (PDDA) with the photoactive polyanion (PAZO) were used in order to fabricate the multilayers. After achieving the desired number of layers and treatment with a phosphate buffer solution at pH=7.0, Fibrinogen was injected and adsorption was monitored using QCM. We observed a higher change in