Collier Bradley B, McShane Michael J
Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843.
Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843 ; Department of Materials Science and Engineering Program, Texas A&M University, College Station, TX 77843.
Proc SPIE Int Soc Opt Eng. 2015 Feb;8591. doi: 10.1117/12.2001840.
Due to the increasing prevalence of diabetes, research toward painless glucose sensing continues. Oxygen sensitive phosphors with glucose oxidase (GOx) can be used to determine glucose levels indirectly by monitoring oxygen consumption. This is an attractive combination because of its speed and specificity. Packaging these molecules together in "smart materials" for implantation will enable non-invasive glucose monitoring. As glucose levels increase, oxygen levels decrease; consequently, the luminescence intensity and lifetime of the phosphor increase. Although the response of the sensor is dependent on glucose concentration, the ambient oxygen concentration also plays a key role. This could lead to inaccurate glucose readings and increase the risk of hyper- or hypoglycemia. To mitigate this risk, the dependence of hydrogel glucose sensor response on oxygen levels was investigated and compensation methods explored. Sensors were calibrated at different oxygen concentrations using a single generic logistic equation, such that trends in oxygen-dependence were determined as varying parameters in the equation. Each parameter was found to be a function of oxygen concentration, such that the correct glucose calibration equation can be calculated if the oxygen level is known. Accuracy of compensation will be determined by developing an overall calibration, using both glucose and oxygen sensors in parallel, correcting for oxygen fluctuations in real time by intentionally varying oxygen, and calculating the error in actual and predicted glucose levels. While this method was developed for compensation of enzymatic glucose sensors, in principle it can also be implemented with other kinds of sensors utilizing oxidases.
由于糖尿病的患病率不断上升，无痛葡萄糖传感的研究仍在继续。带有葡萄糖氧化酶（GOx）的氧敏磷光体可通过监测氧气消耗来间接测定葡萄糖水平。由于其速度和特异性，这是一种有吸引力的组合。将这些分子包装在用于植入的“智能材料”中，将实现无创葡萄糖监测。随着葡萄糖水平升高，氧气水平降低；因此，磷光体的发光强度和寿命增加。尽管传感器的响应取决于葡萄糖浓度，但环境氧浓度也起着关键作用。这可能导致葡萄糖读数不准确，并增加高血糖或低血糖的风险。为了降低这种风险，研究了水凝胶葡萄糖传感器响应与氧气水平的相关性，并探索了补偿方法。使用单一通用逻辑方程在不同氧浓度下对传感器进行校准，以便将氧依赖性趋势确定为方程中的可变参数。发现每个参数都是氧浓度的函数，这样如果已知氧水平，就可以计算出正确的葡萄糖校准方程。补偿的准确性将通过进行全面校准来确定，同时并行使用葡萄糖和氧传感器，通过有意改变氧气实时校正氧气波动，并计算实际和预测葡萄糖水平的误差。虽然这种方法是为补偿酶促葡萄糖传感器而开发的，但原则上它也可以用于其他利用氧化酶的传感器。
