Towards cost-effective and lightweight surface plasmon resonance biosensing for H5N1 avian influenza virus detection: Integration of novel near-infrared organic photodetectors

H5N1 avian influenza virus (AIV) persists in causing highly fatal human infections, demanding rapid and accurate diagnostic assessment. In this study, we introduce an intensity-based SPR sensor utilizing NIR wavelength excitation in tandem with a specifically engineered NIR-OPD. The active layer of the OPD consists of a PTB7-Th and COTIC-4 F blend, offering an optimized response for a 980 nm excitation wavelength. Key performance metrics of this OPD include a low Jd of 0.185 nA/cm2, a high responsivity of 0.35 A/W, an EQE of 44.74%, and an exceptional detectivity of 4.59 x 1013 Jones at 980 nm wavelength under zero bias. It also exhibits a wide LDR of 113 dB. The integration of such OPDs into our SPR sensor provides advantages in compactness and cost-effectiveness. Employing this sensor, we detected the H5N1 AIV using a custom high-affinity polyclonal anti-body against HA envelope of the H5N1 virus, completing analyses of culture medium samples within 12 min. The detection limit of this biosensor for the H5N1 AIV in PBS-diluted culture medium is approximately 4.3 x 104 copies/mL. When compared to a commercial H5-Ag lateral flow test kit, our biosensor showed a sensitivity 37 times higher. Key attributes of our biosensor include 3D printing technology for easy alignment of optical components and a rapid, simplified detection procedure. Collectively, our findings open up the potential of our SPR biosensor as an efficient tool for detecting H5N1 AIV, promising advancements in on-site detection methodologies.