Direct electron transfer from native human hemoglobin using a glassy carbon electrode modified with chitosan and a poly(N,N-diethylacrylamide) hydrogel containing red blood cells

We report on a new whole cell biosensor for hydrogen peroxide. A chitosan-coated glassy carbon electrode (GCE) was modified with poly(N,N-diethylacrylamide) (PDEA) hydrogel containing human red blood cells (RBCs). The morphology of RBCs in the hydrogel was investigated using scanning electron microscopy (SEM). Fourier transform infrared spectroscopy and SEM were applied to study the association of the PDEA chains and RBCs. Uncompromised bioactivity of native human hemoglobin in the RBCs on the modified GCE was confirmed by cyclic voltammetry. The modified electrode showed a faster electron transfer rate and better electrocatalytic activity in the reduction of H 2 O 2 than previously reported sensors. A linear relationship is found between the response to H 2 O 2 and its concentration in the range from 0.11 μM to 12.7 mM. The detection limit is 55 nM at an SNR of 3. It is assumed that the improvement of the biosensor results from the porosity and conductivity of the PDEA hydrogel. With the presence of poly(N,N-diethylacrylamide) chains, our novel red blood cells based biosensor displays a fast electron transfer rate and excellent electrocatalytic activity to H 2 O 2 . It responds to H 2 O 2 in the concentration range from 0.11 μM to 12.7 mM, and the detection limit is 55 nM (at an SNR of 3).