Improvement of Biomolecule Immobilization on Polystyrene Surface by Increasing Surface Roughness

Abstract

Fast growing used of QCM biosensor has been reported. It is well known that the QCM sensor responses both to mass or viscosity changes. In its operation as mass sensitive sensor, a QCM responses to the mass change per surface area. In the use of QCM biosensor, immobilization of the bio sensitive layer on top of the sensor surface is one of the importance factors. The immobilization of the biomolecule can be done directly on top of the sensor electrode or by using a coating material as supporting matrix. This experiment shows that the use of thick polystyrene coating with a rough surface resulted from air brush technique resulted in a significant improvement on the biomolecule immobilization compare to the polystyrene coating using spin coating method. As there is no chemical or physical modification on the polystyrene coating, the increasing numbers of the immobilized biomolecule merely a result of the surface geometry. The increasing number of immobilized biomolecule is caused by improving total surface area per perpendicular surface area of the sensor by introducing surface roughness. However, an appropriate care must be taken during the coating process to avoid over rough surface which in turn can heavily damp the QCM sensor.