Optical Nanosensors for Real‐Time Feedback on Insulin Secretion by β‐Cells
Roni Ehrlich, Adi Hendler‐Neumark, Verena Wulf, Dean Amir, Gili Bisker
Abstract
Abstract Quantification of insulin is essential for diabetes research in general, and for the study of pancreatic β‐cell function in particular. Herein, fluorescent single‐walled carbon nanotubes (SWCNT) are used for the recognition and real‐time quantification of insulin. Two approaches for rendering the SWCNT sensors for insulin are compared, using surface functionalization with either a natural insulin aptamer with known affinity to insulin, or a synthetic lipid‐poly(ethylene glycol) (PEG) (C 16 ‐PEG(2000Da)‐Ceramide), both of which show a modulation of the emitted fluorescence in response to insulin. Although the PEGylated‐lipid has no prior affinity to insulin, the response of C 16 ‐PEG(2000Da)‐Ceramide‐SWCNTs to insulin is more stable and reproducible compared to the insulin aptamer‐SWCNTs. The SWCNT sensors successfully detect insulin secreted by β‐cells within the complex environment of the conditioned media. The insulin is quantified by comparing the SWCNTs fluorescence response to a standard calibration curve, and the results are found to be in agreement with an enzyme‐linked immunosorbent assay. This novel analytical tool for real time quantification of insulin secreted by β‐cells provides new opportunities for rapid assessment of β‐cell function, with the ability to push forward many aspects of diabetes research.