In vivo monitoring of blood glucose using poly(ethylene glycol) microspheres

摘要

A preliminary in vivo study using photopolymerized poly(ethylene glycol) (PEG) microspheres containing tetramethylrhodamine isothiocyanate labeld concanavalin A (TRITC-Con A) fluroescein isothiocyanate labeld dextran (FITX-dextran) as an implantable glucose sensor was performed using hairless rats. The glucose sensor works by affinity reaction between the two fluorescent labeled molecules binding together to form a fluorescent energy transfer system in which the FITC peak is quenched by the TRITC peak. The addition of glucose to the sensors local environment displces the dextran disrupting the FRET pair and the quenching. The change in fluroescent peak ratio (TRITC/FITC) therefore can be related to glucose. The microspheres in this study were implanted below the dermal skin layer of the lower abdomen by injection. A bolus injection of glucose was given through the tail vein to simulate glucose consumption. Spectra were obtained by shining and collecting light through the skin using an optical fiber delivery system via a 488nm argon laser and a spectrophometer. The preliminary results showed quantifiable changes in the ratio between the two peaks in response to the changae in glucose levels in the interstitial fluid of the rat.