Functionalized graphene oxide for clinical glucose biosensing in urine and serum samples

Murugan Veerapandian,¹ Yeong-Tai Seo,² Hyunkyung Shin,³ Kyusik Yun,¹ Min-Ho Lee<sup>4

1</sup>Department of Bionanotechnology, Gachon University, Gyeonggi-Do, ²School of Electrical Engineering and Computer Science, Seoul National University, Seoul, ³Department of Mathematics and Information, Gachon University, Gyeonggi-Do, ⁴Korea Electronics Technology Institute, Medical IT Technology, Gyeonggi-Do, Republic of Korea

Abstract: A novel clinical glucose biosensor fabricated using functionalized metalloid-polymer (silver-silica coated with polyethylene glycol) hybrid nanoparticles on the surface of a graphene oxide nanosheet is reported. The cyclic voltammetric response of glucose oxidase modification on the surface of a functionalized graphene oxide electrode showed a surface-confined reaction and an effective redox potential near zero volts, with a wide linearity of 0.1–20 mM and a sensitivity of 7.66 µA mM^-1 cm^-2. The functionalized graphene oxide electrode showed a better electrocatalytic response toward oxidation of H₂O₂ and reduction of oxygen. The practical applicability of the functionalized graphene oxide electrode was demonstrated by measuring the peak current against multiple urine and serum samples from diabetic patients. This new hybrid nanoarchitecture combining a three-dimensional metalloid-polymer hybrid and two-dimensional graphene oxide provided a thin solid laminate on the electrode surface. The easy fabrication process and retention of bioactive immobilized enzymes on the functionalized graphene oxide electrode could potentially be extended to detection of other biomolecules, and have broad applications in electrochemical biosensing.

Keywords: clinical diagnostics, glucose biosensor, metalloid-polymer nanoparticles, glucose oxidase, cyclic voltammetry