Development of methods for functionalization of screen printed electrodes with biocompatible organic-inorganic hybrid nanocomposites for biosensing applications

New types of organic-inorganic hybrid nanocomposites based on nanosized titanium oxide(IV) (TiO₂, particle size <100 nm) and carbon nanotubes (CNT, outer diameter of 10–15 nm, inner diameter of 2–6 nm, and length of 0.1–10 μm) and phosphatidylcholine were elaborated for improvement of analytical characteristics of screen printed electrodes. These nanomaterials were employed as an interface for immobilization of skeletal myoglobin. Electroanalytical and electrokinetic behavior of myoglobin on such interfaces was characterized with cyclic voltammetry (CV) and square wave voltammetry (SWV). Direct unmediated electron transfer between heme of immobilized myoglobin and electrodes modified with titanium oxide or carbon nanotubes was registered. The midpoint (redox) potential of the myoglobin Fe³⁺/Fe²⁺ E _1/2 = ?0.263 V for electrodes modified with CNT and E _1/2 = ?0.468 V for electrodes modified with TiO₂ was observed (vs. Ag/AgCl reference electrode).