3D-phosphorus doped mesoporous graphitic carbon nitride based immunosensor for swine flu detection

The present study concerns the exposure and transmission of virus-borne disease and the protein serum amyloid A (SAA), which may act as a hallmark biomarker for swine flu (SF) detection. The concentration of SAA protein in the serum of a normal subject is 12.2 +/- 15.0 mu g mL(-1), which increases to 49.4 +/- 14.1 mu g mL(-1) in a SF-infected patient. In the present work, we have developed an immunosensor platform for SF detection. For this, three dimensional (3D)-phosphorus doped porous graphitic carbon nitride (P-g-C3N4) was synthesized via a chemical process and functionalized with serine (Ser) molecules. The functionalized nanomaterial (Ser/P-g-C3N4) was electrophoretically deposited onto an indium tin oxide (ITO) coated glass electrode. The prepared Ser/P-g-C3N4/ITO electrode was biofunctionalized via covalent immobilization of anti-SAA antibodies and then incubated with bovine serum albumin molecules for non-specific site blocking. Structural, morphological, chemical, and surface analysis studies of the synthesized nanomaterial and fabricated electrodes were carried out using X-ray diffraction, Brunauer-Emmett-Teller theory, Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy, field emission scanning electron microscopy, and transmission electron microscopy techniques. Electrochemical characterization and analytical evaluation/studies of the fabricated electrodes were performed using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy techniques. The fabricated immunosensor, i.e., BSA/anti-SAA/Ser/P-g-C3N4/ITO, is capable of providing a sensitive and specific response to SAA protein in an analytical solution over the concentration range of 10 ng mL(-1) to 100 mu g mL(-1), with a lower detection limit of 10 ng mL(-1), excellent sensitivity of 23.9 mu A log (mL ng(-1)) cm(-2), and quick analysis time (10 min). Comprehensively, the fabricated immunosensor was also used to analyze SAA protein in spiked serum samples, which resulted in a good correlation with the electrochemical response observed in standard SAA protein samples in analytical solution.

Automated summary

The present study developed an immunosensor for swine flu detection. Functionalized nanomaterial was synthesized and a specific electrode was fabricated. The immunosensor showed sensitive and specific response to SAA protein with low detection limit and quick analysis time.