Real-time detection of prostate-specific antigens using a highly reliable fiber-optic localized surface plasmon resonance sensor combined with micro fluidic channel

Abstract

Conventional assays using fiber-optic localized surface plasmon resonance (FO LSPR) sensors involve soaking the sensor in solution, which exposes the sensor to air during measurement. Although the exposure time is short, for a small sensor surface area, this can result in drying of biomolecules and rearrangement of nanoparticles caused by the surface tension. To minimize the resulting errors, FO LSPR sensor was combined with a micro fluidic channel. To verify the improved performance of the sensor chip combined with a micro fluidic channel, we conducted real-time detection of various concentrations of prostate-specific antigen (PSA). A calibration method was used to correct nonuniformity among the detected PSA results, arising from differences in sensors because of nonuniform metal nanoparticles on the sensor surface. A micro fluidic channel and calibration increased linearity and improved the sensitivity and dynamic range of PSA measurements. Additionally, the fabricated sensors were applied to detect the test samples and the measured sample concentrations were compared to actual values. Confirming the selectivity towards the target, the proposed system detected the control antigen. Finally, we used our sensor system to detect PSA in patient serum and acquired comparable results to those obtained using a commercialized method.