Using Polyethylene Glycol-Modified Chitosan for Improvement of Carbohydrate Antigen 15-3 Detection on a Quartz Crystal Microbalance Biosensor

In this paper, an improvement method for detection of tumor marker with a label-free biosensor is reported. The polyethylene glycol (PEG)-modified chitosan hydrogel as a biosensing interfacial architecture was formed on the gold surface and its potential was evaluated with a quartz crystal microbalance (QCM). This hydrogel was modified to increase its negative charges and then use electrostatic interactions with the positive charges of the amine surfaces. The biosensing application was investigated by use of the antibody antigen model system of carbohydrate antigen 15-3 (CA15-3), an important indicator in the prognosis of breast cancer. Compared to the covalent immobilization method, the QCM biosensor with the proposed immobilization showed improved sensitivity. In addition, the regeneration of the developed immunosensor was obtained after the release by rinsing the sensor with glycine/HCl solution. Based on these results, it was believed that such a three-dimensional polyelectrolyte multilayer can be applied to the development of immunoassays.