Invasive Monitoring of Blood Glucose

Fewer than 10% of patients with diabetes routinely perform SMBG because it is painful and inconvenient Since the 1960s, attempts have been made to develop a painless method for monitoring blood glucose concentrations. Three general approaches have been used, namely implanted sensors, minimally invasive monitoring, and noninvasive monitoring. 

Several implanted biosensors have been developed and evaluated in both animals and humans (see Chapter 4). Detection systems are based on enzymes, electrodes, or fluorescence. The most widely studied method is an electrochemical sensor that uses glucose oxidase. This sensor can be implanted intravenously or subcutaneously. Intravenous implantation in dogs for up to 3 months has demonstrated the feasibility of this approach. Alternatives to enzymes are being developed, including artificial glucose receptors. Less success has been achieved with subcutaneous implants. Implantation of a needle type of sensor into the subcutaneous tissue induces a host of inflammatory responses that alters the sensitivity of the device. Microdialysis with hoUow fibers or ultrafiltration with biologically inert material can decrease this problem. 

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