CuS thin films coated with bioglass 45S5/TiO 2 Nps and CuS/Zeolite ZMS5/1.5 [Ti] for urea biosensing applications

In this article, the implementation of chalcogenide semiconductor and bioceramics thin films to sense urea is reported. The CuS semiconductor was deposited over rigid substrates by chemical bath technique, characterized optically and electrically. Bioglass 45S5/TiO 2 Nps and zeolite ZMS5/1.5 [Ti] functioned as immobilization matrix for urease enzyme, and bioceramics materials were synthesized by sol–gel method and deposited over the semiconductor thin film by spin coating technique at room temperature. In the final system, a channel and a porous microstructure were observed by scanning electron microscopy (SEM), suitable to immobilize enzymes in the system, appreciating the two phases coated over the substrates. The chemical, optical, and electrical changes of the CuS/bioglass 45S5/TiO 2 Nps and CuS/zeolite ZMS5/1.5 [Ti] before and after the urea test have also been reported. The ammonium absorption border showed a proper urease immobilization by adsorption in the bioceramic matrices, ensuring a reaction with urea being sensed with UV–Vis characterization. Also, the thin film system exhibited an increase in resistivity as the urea concentration increased, measured by a four-probe method, correlating the correct immobilization and detection of the analyte.