A fluorescent double-network-structured hybrid nanogel as embeddable nanoglucometer for intracellular glucometry.

The development of embeddable and remotely interrogatable nanomaterials that allow dynamic quantification of intracellular glucose levels can contribute to a better understanding of physiology. We develop a fluorescent hybrid nanogel glucometer (FNG) that is applicable for intracellular glucometry. Such a FNG (<200 nm) is comprised of ZnO quantum dots covalently bonded onto a loosely-crosslinked gel network of poly(acrylamide), which is interpenetrated in another relatively highly-crosslinked gel network of poly(N-isopropylacrylamide-co-2-acrylamidomethyl-5-fluorophenylboronic acid). This newly developed double-network-structured FNG can adapt to surrounding media of varying glucose levels, and convert the disruptions in homeostasis of glucose level with high reversibility, sensitivity, and selectivity into fluorescence signals at a fast time response. We demonstrate that the FNG can enter the model B16F10 cells and employ the signal transduction ability for fluorescent intracellular glucometry. Furthermore, we show that intracellular glucose level variations associated with a model biological reaction process can be monitored with a high glucose resolution by using the FNG embedded in cells, whilst the reaction mechanism remains nearly unchanged.