(275a) Nanosensors-Encapsulated Microcapsule for Glucose Sensing

Non-invasive implantable systems that are able to continuously track blood glucose levels are needed for diabetes diagnostics and monitoring. Although many nanomaterial colloidal solutions have been developed as optical sensors to detect glucose in aqueous samples, the liquid nature of these sensor solution limits their applications as implantable devices for glucose sensing in vivo. One potential solution is embedding the nanosensors in biocompatible hydrogel matrix, yet the direct contact between the sensor surface and the polymer chains of the hydrogel tends to disrupt the performance and sensitivity of the sensors. In this work, glucose responsive nanosenors were encapsulated in liquid-core microcapsules. Glucose is allowed to diffuse through the capsule shell freely, while the nanosensors are trapped inside the capsules without leaking away. The interaction between glucose and the nanosensors produces detectable optical signals. The microcapsules were fabricated by forming water-oil-water template double emulsion using microfluidic techniques. The capsules' stability and permeability to glucose were demonstrated. Three types of glucose-responsive nanosensors, glucose oxidase (GOx)-functionalized quantum dots, GOx-functionalized gold nanorods, and boronic acid-functionalized carbon nanotubes, were encapsulated in the microcapsules individually, and they responsively exhibited optical signals in the present of glucose. Furthermore, implantable devices were fabricated by embedding these capsules in calcium alginate hydrogel, and their responses to glucose were demonstrated.