Feasible electrochemical biosensor based on plasma polymerization-assisted composite of polyacrylic acid and hollow TiO2 spheres for sensitively detecting lysozyme

A composite made of polyacrylic acid and hollow TiO 2 spheres (TiO 2 @PPAA) was prepared by the plasma polymerization method and subsequently used as an electrode material for detecting lysozyme . The chemical structure, surface morphology , and electrochemical performance of the TiO 2 @PPAA composite were mainly affected by the plasma input power used during plasma polymerization. After optimizing plasma conditions, aptamer strands exhibited high adsorption affinity toward the surface of TiO 2 @PPAA composite via synergistic effects between TiO 2 and PPAA. Electrochemical impedance spectroscopy results showed that the developed TiO 2 @PPAA aptasensor presents highly sensitive detection ability toward lysozyme; the limit of detection of the proposed aptasensor is 0.015   ng   mL −1 (1.04   pM) within the range of 0.05–100   ng   mL −1 in terms of 3 σ value. The film further showed excellent selectivity toward lysozyme in the presence of interfering proteins, such as thrombin, bovine serum albumin , and immunoglobulin E. Thus, this aptasensing strategy might broaden the applications of plasma polymerized nanomaterials in the field of biomedical research and early clinical diagnosis.