Electrochemical biosensing based on protein-directed carbon nanospheres embedded with SnOx and TiO2 nanocrystals for sensitive detection of tobramycin

A series of nanocomposites comprised of homogeneous mesoporous carbon nanospheres embedded with SnOx (x = 0, 1, or 2) and TiO2 nanocrystals using bovine serum albumin (BSA) as template followed by calcinated at different temperatures (300, 500, 700, and 900 °C) were prepared, and were denoted as SnOx@TiO2@mC. Then a novel electrochemical biosensing strategy for detecting tobramycin (TOB) based on the nanocomposites was constructed. The as-prepared SnOx@TiO2@mC nanocomposites not only possess high specific surface area and good electrochemical activity but also exhibit strong bioaffinity with the aptamer strands, therefore, they were applied as the scaffold for anchoring TOB-targeted aptamer and further used to sensitively detect trace TOB in aqueous solutions. By comparing the electrochemical biosensing responses toward TOB detection based on the four SnOx@TiO2@mC nanocomposites, the biosensing system constructed with SnOx@TiO2@mC900 (derived at 900 °C) demonstrated the highest determination efficiency, high selectivity, and good stability. In particular, the new proposed aptasensing method based on SnOx@TiO2@mC nanocomposite exhibits considerable potential for the quantitative detection of TOB in the biomedical field.