Graphene dispersed cellulose microfibers composite for efficient immobilization of hemoglobin and selective biosensor for detection of hydrogen peroxide

- Preparation of a novel and highly stable GR-CMF composite
- Electrochemical behavior of Hb was studied at Hb immobilized GR-CMF composite
- The high ks of 6.17 s−1 was achieved for Hb immobilized GR-CMF composite
- A lower LOD (10 nM) was obtained for H2O2 using Hb immobilized GR-CMF composite

In the present work, we have investigated the electrochemical behavior and electrocatalysis of hemoglobin (Hb) immobilized on a glassy carbon electrode (GCE) modified with a graphene-cellulose microfiber (GR-CMF) composite. The GR-CMF composite was characterized by scanning electron microscopy, elemental analysis, and Raman and Fourier transform infrared spectroscopy. Well-defined electrochemical redox characteristics of Hb were observed for Hb immobilized on a GR-CMF composite modified GCE, with a formal potential of −0.306 V and a peak to peak separation of approximately 67 mV. Due to the high biocompatibility of the GR-CMF composite, the electrochemical behavior of the Hb heme redox couple (FeII/FeIII) was enhanced for Hb immobilized on the GR-CMF composite when compared to Hb immobilized on pristine GR. The heterogeneous electron transfer constant (ks) was calculated as 6.17 s−1, and is higher than previously reported for Hb immobilized GR supports. The Hb immobilized GR-CMF composite modified electrode was used for the quantification of H2O2 under optimal conditions, and shows a wider linear amperometric response ranging from 0.05 to 926 μM. The limit of detection of the biosensor was 0.01 μM with the sensitivity of 0.49 μA μM−1 cm−2. The biosensor also showed high selectivity in the presence of the range of interfering compounds and exhibits good operational stability and practicality in the detection of H2O2.