Development of SPR biosensor for the detection of human hepatitis B virus using plasma-treated parylene-N film

•A plasma-treated parylene-N film was presented to improve the protein immobilization.•The surface properties were analyzed using contact angle measurement and AFM.•The immobilization efficiency was estimated using proteins with different isolelectric points.•The plasma-treated paryelne-N film was applied to SPR biosensor to improve the sensitivity.•A SPR biosensor for HBsAg was developed by using the plasma-treated parylene-N film.

A plasma-treated parylene-N film was presented for the immobilization of proteins through physical adsorption. The changes in surface properties of the parylene-N film after plasma-treatment were analyzed using contact angle microscopy and AFM. To demonstrate the high protein-immobilization efficiency of the plasma-treated parylene-N film, the immobilization efficiencies of differently modified surfaces were compared using model proteins with different surface charges, such as streptavidin (pI=5, negatively charged at pH 7), horseradish peroxidase (pI=6.6, nearly neutral at pH 7), and avidin (pI=10, positively charged at pH 7). The application of the plasma-treated parylene-N film as an SPR biosensor was also tested by immobilizing model proteins. An SPR biosensor based on the plasma-treated parylene-N film was developed for the detection of the human hepatitis virus surface antigen (HBsAg), and the plasma-treated parylene-N film was estimated to improve the sensitivity of SPR biosensor as much as 1000-fold by enhancing immobilization of receptor antibodies.