An immunosensor based on the glucose oxidase label and optical oxygen detection.

A novel optical immunosensor setup is described which uses glucose oxidase enzyme as a label in conjunction with a luminescence lifetime-based oxygen sensor and phase measurements. The oxygen sensor membranes prepared on microporous filters were used as a solid phase on which the immunoassay was carried out. These sensing materials in combination with a new measurement setup provided high sensitivity for the detection of oxidase enzymes, being at nanogram per milliliter level, i.e., 10-11−10-12 M, with respect to glucose oxidase and its conjugates. Experimental data on the sensitivity were validated using theoretical equations and calculations. Using the new measurement setup and IgG−anti-IgG as a model, a number of different sensing materials were studied aimed to optimize the immunosensor and evaluate its performance. This approach was then applied to a practical system for the detection of human lactate dehydrogenase isoenzymes. It provided similar sensitivity of ∼1 ng/mL, which is comparable to that o...