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Wound healing is a critical challenge in diabetic patients, mainly due to long-term dysglycemia and its related pathological complications. Subcutaneous insulin injection represents a typical clinical solution, while the low...

Biosensing is a rising analytical field for detection of biological indicators using transducing systems. Smart materials can response to external stimuli, and translate the stimuli from biological domains into signals that are readable and quantifiable. Smart materials, such as nanomaterials, photonic crystals and hydrogels have been widely used for biosensing purpose. In this review, we illustrate the incorporation of smart materials in biosensing systems, including the design of responsive materials, their responsive mechanism of biosensing, and their applications in detection of four types of common biomolecules (including glucose, nucleic acids, proteins, and enzymes). In the end, we also illustrate the current challenges and prospective of using smart materials in biosensing research fields.

Background Diabetes is one of the biggest medical challenges worldwide. The key to efficiently treat type 1 diabetes is to accurately inject insulin according to the blood glucose levels. In this study, we aimed to develop an intelligent insulin-releasing gold nanocluster system that responds to environmental glucose concentrations. Results We employed gold nanoclusters (AuNCs) as a novel carrier nanomaterial by taking advantage of their high drug-loading capacity. We prepared AuNCs in the protection of bovine serum albumin, and we decorated AuNCs with 3-aminophenylboronic acid (PBA) as a glucose-responsive factor. Then we grafted insulin onto the surface to obtain the glucose-responsive insulin-releasing system, AuNC-PBA-Ins complex. The AuNC-PBA-Ins complex exhibited high sensitivity to glucose concentration, and rapidly released insulin in high glucose concentration in vitro. In the type 1 diabetic mouse model in vivo, the AuNC-PBA-Ins complex effectively released insulin and regulated blood glucose level in the normoglycemic state for up to 3 days. Conclusions We successfully developed a phenylboronic acid-functionalized gold nanocluster system (AuNC-PBA-Ins) for responsive insulin release and glucose regulation in type 1 diabetes. This nanocluster system mimics the function of blood glucose regulation of pancreas in the body and may have potential applications in the theranostics of diabetes. Electronic supplementary material The online version of this article (10.1186/s12951-019-0505-z) contains supplementary material, which is available to authorized users.

Responsive blood glucose control in a convenient and noninvasive manner is the ultimate goal in diabetes treatment. In this study, we developed a closed-loop microneedle (MN)-array patch for transdermal and responsive insulin delivery in type 1 diabetes therapy. We prepared alginate-based MN-array patches integrated with glucose-responsive gold nanoclusters (GNCs) using a two-step casting and centrifuging process. From both theoretical calculation and experimental study, we found that the integration of GNCs into MNs significantly improved the mechanical strength of alginate-based MN-array patches. The GNCs facilitated the MNs to penetrate the skin of mice, and the glucose-responsive GNCs in MNs allowed the closed-loop insulin release both in vitro in glucose solutions and in vivo in type 1 diabetic mice. With transdermal application only once on the skin of mice, the MN-array patches regulated the blood glucose levels of mice in normoglycemic ranges for up to 2.8 days and decreased the diabetic symptoms of the mice. Our study proved the successful application of glucose-responsive GNC-loaded MN-array patches for minimally invasive and responsive insulin delivery, providing a promising alternative for type 1 diabetes therapy.