Abstract
The development of sensing systems that can detect ultra-trace amounts of hydrogen peroxide (H2O2) remains a key challenge in biological and biomedical fields. In the present study, we introduce a simple and highly sensitive enzymeless H2O2 biosensor based on a three-dimensional open pore nickel (Ni) foam electrode functionalized with hemoglobin (Hb). Our findings revealed that the Hb maintained its biological functions and effective electronic connection even after immobilization process. The exceptional physical and intrinsic catalytic properties of the Ni foam combined with the bio-functionality and electron transport facility of the Hb robustly construct a H2O2 biosensor. The enzymeless H2O2 biosensor showed high selectivity, a quick response time, high sensitivity, a wide linear range and a low limit of detection (0.83 μM at a signal-to-noise ratio of three). Such an electrode composition with safe immobilization processes offers viability for engineering new biosensors.
Highlights
There is a growing demand worldwide to develop efficient sensing systems with high flexibility and low capital cost for control recognition and real-time monitoring of toxic analytes and biological molecules at very low concentrations [1]
3D porous Nickel foam (Ni foam) was used as a substrate for the immobilization of Hb to improve the energy density of the electrochemical sensor at high rates
This successful immobilization of Hb onto 3D Ni foam might enhance the kinetics of ion and electron transport in the Ni foam electrode, at the electrode-electrolyte interface and to engage sufficient electro-active species exposed on the surface for the faradaic redox reaction, as evidenced by the SEM profile, energy-dispersive X-ray (EDX) and WCAs analyses
Summary
There is a growing demand worldwide to develop efficient sensing systems with high flexibility and low capital cost for control recognition and real-time monitoring of toxic analytes and biological molecules at very low concentrations [1]. Porous materials have attracted much attention because of their high porosity, stability, mechanical strength, relatively low toxicity and mass transfer ability [3] They are promising candidates in a plethora of technologically important disciplines, including environmental capture, sensor design, nanofiltration and fuel cells [4]. Porous metallic materials possessing high specific surface areas and an open-pore architecture, namely metallic foams, offer unique physical and chemical characteristics to interact with atoms, ions and molecules along the porous network [5] These attractive features of metallic foam make it a suitable material for a wide range of potential applications, such as catalysts [6], separation systems [7], chemical sensors [8] and electrochemical applications (water electrolyzers, alkaline fuel cells, electrochemical supercapacitors, electrochromic devices and alkaline batteries) [9]. Electro-catalytic oxidation of H2O2 over Ni foam decorated by Hb
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