Pore size effect in the amount of immobilized enzyme for manufacturing carbon ceramic biosensor

Abstract Understanding the mechanism of enzyme immobilization in porous designed matrices is important issue to develop biosensors with high performance. Mesoporous carbon ceramic materials with conductivity and appropriated textural characteristics are promising candidates in this area. In this work, carbon ceramic materials were synthesized using the sol-gel method by planning the experimental conditions to obtain materials with different pore size, from 7 to 21 nm of diameter. The study of the influence of pore size in the biomacromolecules immobilization capacity was performed using glucose oxidase enzyme as probe. The influence of textural characteristics of material in the amount of enzyme immobilized, as well as, its performance as biosensor, was studied. On the surface of highest pore size matrix, it was possible to immobilize the highest amount of enzyme, resulting in better electrochemical response. With this simple material, composed only by silica, graphite and enzyme, which was improved by the amount of immobilized enzyme through the enlargement of matrix pore size, it was possible to prepare an electrode to be applied as biosensor for glucose determination. This electrode presents good reproducibility, sensitivities of 0.33 and 4.44 μA mM −1  cm −2 and detection limits of 0.93 and 0.26 mmol L −1 , in argon and oxygen atmosphere, respectively. Additionally, it can be easily reused by simple polishing its surface.