Direct Electron Transfer and Direct Bioelectrocatalysis of Sarcosine Oxidase on Ti3c2tx Mxene Hybrid Interface

• DOI: 10.2139/ssrn.4965280
• Publication Date: 2024-09-24T18:00:42Z
• Authors: Jan Tkac; Lenka Lorencova; Stefania Hroncekova; Peter Kasak; Monika Jerigova; Lubomir Orovcik
• Keywords: Sarcosine; Interface (matter)

Abstract The current study shows a direct electron transfer (DET) and direct bioelectrocatalysis of the sarcosine oxidase (SOx) on the screen-printed carbon electrode (SPCE) modified by a hybrid bionanocomposite composed of chitosan (CS) and Ti3C2Tx MXene for the first time. A detailed electrochemical investigation revealed a pair of redox peaks at SPCE/CS-MXene/SOx, i.e. an anodic peak at a potential value of approx. -0.7 V and a cathodic peak at a potential value of approx. -1.0 V at pH 7.0, displaying direct electron transfer of SOx. Further experiments showed homogeneous DET with SOx not to be strongly adsorbed on the interface; this might be a prerequisite for keeping the enzyme active towards catalysis. The DET of SOx is not reversible with the maximal current observed at pH 7.0. It can also be concluded that scan rate significantly influences the redox behaviour of SOx and that at scan rates above 0.3 V s−1 the redox behaviour of SOx is quite stable with I pc/I pa achieving a stable value of -1.55. In addition, detailed analysis revealed that the enzyme exhibited E 1/2 of -(0.781 ± 0.003) V at pH 7.0. Direct bioelectrocatalysis is more effective at pH 7.0 than at pH 9.0, achieving a high maximal current of -7.57 × 10−5 A at a potential value of -663 mV upon the addition of 1 mM sarcosine. Furthermore, direct bioelectrocatalysis of SOx is highly reproducible when examined using six different SPCE electrodes.