Kinetically Doped Silica Sol–Gel Optical Biosensors: Expanding Potential Through Dip-Coating

Abstract

Kinetic doping has previously been shown to be an effective method of doping silica sol–gel thin films with an enzyme to construct biosensors. Until now, kinetic doping has only been applied to films produced through the spin-coating method. In this study, we present the use of dip-coating to produce thin films kinetically doped for biosensor development. In this way, kinetically doped biosensors may benefit from the increased range of substrate material shapes and sizes that may be easily coated through dip-coating but not spin-coating. The biosensors produced through dip-coating continue to show enhanced performance over more conventional enzyme loading methods with horseradish peroxidase and cytochrome C samples, showing an increase of 2400× and 1300× in enzyme concentration over that in their loading solutions, respectively. These correspond to enzyme concentrations of 5.37 and 10.57 mmol/L all while preserving a modest catalytic activity for the detection of hydrogen peroxide by horseradish peroxidase. This leads to a 77% and 88% increase in the total amount of horseradish peroxidase and cytochrome C, respectively, over that from coating the same glass coverslip via spin-coating methods.