Electrochemical investigations into enzymatic polymerisation of 1,10-phenanthroline-5,6-dione as a redox mediator for lactate sensing

Abstract

Lactate biosensor fabrication using a chitosan and crosslinker configuration realised solution mediation (K3Fe(CN)6) with lactate linear range 9.9 × 10−4 to 5.66×10−3 M, sensitivity 1.44×10−3C cm−2 mM−1 and LOD of 0.54 mM. Further development involved use of the heterocyclic quinoid species 1,10-phenanthroline-5,6-dione which acted as a proton and electron acceptor in relation to FADH2 cofactor regeneration. Graphite ink was formulated and utilised as an underlying conductive layer for LOx enzyme immobilisation and enzymatic polymerisation of 1,10-phenanthroline-5,6-dione at a GC electrode, resulting in a linear range of 0.74 – 2.44×10−3 M, sensitivity of 4.11×10−4C cm−2 mM−1 and LOD of 0.06 mM. Scanning electron and electrochemical scanning microscopy realised surface characterisation of the enzyme layers.