Urchin-like PtNPs@Bi₂S₃: synthesis and application in electrochemical biosensor

Efficient urchin-like Pt nanoparticles@Bi₂S₃ (PtNPs@Bi₂S₃) composite materials were prepared by a composite soft template synthesis of urchin-like Bi₂S₃ and then the microwave-assisted growth of PtNPs onto the Bi₂S₃ nanostructure. For the first time, an accurate electrochemical glucose biosensor was fabricated via immobilizing glucose oxidase (GOx) on PtNPs@Bi₂S₃. The PtNPs@Bi₂S₃ composite was investigated via scanning electron microscopy, electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, and cyclic voltammetry. The PtNPs@Bi₂S₃ composite provides a large surface area to load a large number of enzyme molecules, which maintains the biological activity. PtNPs loaded on Bi₂S₃ enhanced the conductivity and improved the direct electron transfer of the proposed biosensor with the synergistic effect. The fabricated electrochemical biosensor possesses high sensitivity, and a wide linear range from 0.003 mM to 0.1 mM and 0.1 mM to 1.9 mM. Moreover, the biosensor has outstanding stability, superior selectivity and good repeatability, which can be utilized to monitor the glucose level in practical human serum. The PtNPs@Bi₂S₃ composite supplies a special matrix for immobilizing proteins and potential for establishing other effective biosensors.