TiC nanoparticles-chitosan composite film for the direct electron transfer of myoglobin and its application in biosensing

We report on the direct electrochemistry of myoglobin (Mb) immobilized on a composite matrix based on chitosan (CHIT) and titanium carbide nanoparticles (TiC NPs) underlying on glassy carbon electrode (GCE). The cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the modified electrode. In deaerated buffer solutions, the cyclic voltammetry of the composite films of Mb-TiC NPs-CHIT showed a pair of well-behaved redox peaks that are assigned to the redox reaction of Mb, confirming the effective immobilization of Mb on the composite film. The electron transfer rate constant was estimated to be 3.8 (± 0.2)·s− 1, suggested that the interaction between the protein and certain electrode surfaces may mimic some physiological situations and may elucidate the relationship between the protein structures and biological functions. The linear dynamic range for the detection of hydrogen peroxide was 0.5–50 μM with a correlation coefficient of 0.999 and the detection limit was estimated at about 0.2 μM (S/N = 3). The calculated apparent Michaelis–Menten constant was 0.07 (± 0.01) mM, which suggested a high affinity of the redox protein–substrate. The immobilized Mb in the TiC NPs-CHIT composite film retained its bioactivity. Furthermore, the method presented here can be easily extended to immobilize and obtain the direct electrochemistry of other redox enzymes or proteins.

Compared with the bare GCE (curve a), CHIT/GCE (curve b) and Mb-CHIT/GCE (curve c), a pair of well-defined and quasi-reversible redox peaks is observed at the Mb-TiC NPs-CHIT/GCE (curve d), suggesting the presence of TiC NPs accelerate the direct electron transfer Mb. The formal potential was − 0.240 V (vs. SCE) and the peak to peak separation was 51 mV.Figure optionsDownload as PowerPoint slideHighlights
► TiC nanoparticles-chitosan composite film as immobilizing matrix realized the direct electrochemistry of myoglobin.
► TiC nanoparticles accelerated the direct electron transfer rate between myoglobin and the substrate electrode.
► The Mb-TiC NPs-CHIT composite film modified electrode showed excellent electrocatalytic ability for H2O2 reduction.