5. An optical biosensor for the rapid determination of glucose in human serum
An optical glucose biosensor based on the immobilization of glucose oxidase in a sensing film was developed. The sensing film consisted of an organically modified silicate film embedded with tri(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) perchlorate and a polyvinyl alcohol sol–gel matrix with immobilized glucose oxidase. A kinetic curve simulation method was employed for glucose measurements, as a result of which the measurement time was less than 1 min for each sample analysis. The detection limit (S/N = 3) of the glucose optical sensor was 3.6×10−6 mol L−1 with linear ranges from 0.00 to 0.50 mmol L−1 (Y = 358.25X−2.93, R2 = 0.9954) and 0.50 to 3.00 mmol L−1 (Y = 430.12X−46.43, R2 = 0.9972). In addition, the appearance of the sensing film, and effects of the amounts of immobilized enzyme, pH, temperature, ionic strength, and co-existing substances (including heavy metal ions and organic compounds) were investigated. The glucose values estimated by this optical biosensor correlated well with those determined using the conventional method for human serum samples.