The Research On Precision Measurement Of Glucose Concentration In Human Interstitial Fluid

The accurate detection of human glucose concentration is the basic and premise work of the prevention and treatment of the diabetes. The conditional ways of glucose detection cannot represent the real fluctuation of blood glucose that occurred in 24 hours. The glucose detection needs to become dynamic and continuous system. In the existing glucose detection methods, the invasive way is not suit for the continuous detection, and the non-invasive optical way is still under research now. So, the minimally-invasive glucose measurement system which is promising to be used in clinic quickly becomes the focus of research worldwide. The exploitation of minimally-invasive glucose measurement system has excellent clinic value and promising market in the treatment of the diabetes.In this thesis, a novel minimally-invasive glucose measurement system based on the measurement of interstitial fluid is proposed. In the detection of concentration of glucose in the interstitial fluid, the approaches to improve the specificity and sensitivity in glucose detection are urgent problems that need to be solved. Surface plasmon resonance (SPR) technique is brought in to build up minimally-invasive glucose measurement system. Combined with D-galactose/D-glucose Binding Protein (GGBP), which can absorb the glucose specially, the minimally-invasive glucose measurement system can estimate the blood glucose concentration through the interstitial fluid. The main works include:1. We analyzed the principle of surface plasmon resonance. We analyzed the way of surface plasmon resonance be inspired. Compared with other different modulation SPR systems, the angular modulation with fixed light source structure is suit for our system. We used the ATR method– Kretschmann geometry to build up SPR system.2. We analyzed the technology of biomolecular interaction analysis used in the SPR system. The GGBP, which can absorb the glucose specially, were mutated at different positions to fit the needs of the measurement of different concentrations of glucose. The GGBP were immobilized on the SPR biosensor using amine coupling way.3. Basing on the miniature surface plasmon resonance sensor, we built up the surface palsmon resonance measurement system. Together with this system, mechanical structure and control software were also developed.4. We analyzed the characteristic of the output signal of surface plasmon resonance system. The simulation and experiment showed that the dynamic baseline method and weigh-centroid algorithm can improve the resolution of SPR system.5. Basing on the surface plasmon resonance measurement system, we carried out the experiments of measuring glucose solution and interstitial fluid. The results showed that:?When the SPR sensor measures the glucose solution directly, the measured refractive index of glucose solution rises linearly with the increase of concentration. The work range include 5mg/dL-20g/dL, and has good linear relationship in 10mg/do-400g/dL. When measures the interstitial fluid, the measured refractive index cannot reflect the real concentration of glucose in interstitial fluid, because of the influence of other components in the interstitial fluid.?The SPR sensors with GGBP mutated at different positions have difference working range. The sensor with GGBP (E149C) has the highest sensitivity. The immobilized SPR sensor succeeds in distinguish the glucose in interstitial fluid.The results reveal a bright future to apply SPR in the minimally-invasive glucose measurement. The innovations of the thesis are:1. In the thesis, GGBP was brought into precision measurement of glucose concentration in human interstitial fluid based on the surface plasmon resonance sensor. With the GGBP, which can absorb the glucose specially, we can realize precision and exclusive measurement of glucose concentration in micro-volume and multi-component human interstitial fluid.2. In the thesis, weigh-centroid algorithm can catch the minimum point of surface plasmon resonance curve. The methods of dynamic baseline with fix calculation points are used to eliminate the fluctuation of surface plasmon resonance curve. The dynamic baseline method and weigh-centroid algorithm can improve the resolution of SPR system.3. In the thesis, surface plasmon resonance glucose measurement system was constructed, which build up the blue print to the miniaturization of glucose concentration in human interstitial fluid.