Optimization of surface plasmon resonance glucose detection based on D-galactose/D-glucose protein amine coupling method

Measuring the glucose concentration of interstitial fluid in human body is an effectively way to control and treat diabetes. A surface plasmon resonance (SPR) system based on a miniature integrated SPR sensor is presented in this paper to measure the glucose concentration in interstitial fluid. D-galactose/D-glucose Binding Protein (GGBP) which can specifically absorb glucose is immobilized onto the SPR sensor surface by amine coupling method for higher sensitivity. The experiment result is affected by various factors, such as baseline, flow velocity, mass transfer effect, temperature, bubbles. In this paper these factors are studied systemically by experiments and some solutions are proposed accordingly: (1) Dynamic baseline can provide the best baseline location during the measurement. (2) Flow velocity of 10uL/min-30uL/min is supposed to be chosen. (3) The density of protein immobilized on the sensor surface should maintain lower to avoid the mass transfer effect. (4) Higher response is got when the temperature is between 26°C and 30°C and it is important to keep temperature constant during the experiment. (5) Samples should be degassed and filtered before the experiment and make sure there is no air in the pipeline. Through optimizing the experiment conditions, the sensitivity and stability of measurement are improved.