In summary, we have developed a label-free electrochemical method for HBV detection based on a gold-specific immobilization strategy. The results showed that optimal concentration of bioreceptor was 50 μg/mL in SPR analysis, and the LOD for HBsAg was about 0.14 ng/mL in the electrochemical analysis. This EIS analysis successfully presents the effectiveness of this sensing platform. Regarding intrinsic advantageous property of the electrochemical assay, such as high sensitivity, simplicity and especially its inherent miniaturization characteristics, and a popular trend of development of electricity-based sensors in everyday life, the proposed method presented in this study has a huge potential in commercialization of a POCT device for viral diagnosis. We have to be conducted with clinical trials in the near future to determine its performance. Development of a Plastic-Based Microfluidic Immunosensor Chip for Detection of H1N1 Influenza Lab-on-a-chip can provide convenient and accurate diagnosis tools. In this paper, a plastic-based microfluidic immunosensor chip for the diagnosis of swine flu (H1N1) was developed by immobilizing hemagglutinin antigen on a gold surface using a genetically engineered polypeptide. A fluorescent dye-labeled antibody (Ab) was used for quantifying the concentration of Ab in the immunosensor chip using a fluorescent technique. For increasing the detection efficiency and reducing the errors, three chambers and three microchannels were designed in one microfluidic chip. This protocol could be applied to the diagnosis of other infectious diseases in a microfluidic device. Swine-origin influenza virus, a high-risk human influenza A virus (H1N1), is a serious health threat and potential leading cause of death all around the World [1] . The World Health Organization (WHO) has reported that more than 16,000 cumulative deaths were reported from 213 countries due to H1N1 in February 2010 [2] . Several laboratory diagnostic methods have been developed to monitor the outbreaks of the virus as follows: (1) specific real-time polymerase chain reaction (PCR)-based detection method, (2) isolation of H1N1 influenza virus, (3) detection of 4-fold rise of neutralization antibodies to the virus [3, 4] . However, these methods require highly skilled-personnel and expensive laboratory instruments. In addition, they are not suitable for undeveloped countries because of the limited access to central laboratories and expensive costs.