Recent advances in the smart insulin delivery systems for the treatment of diabetes

[Display omitted] Diabetes mellitus is an intractable chronic disease manifested as high blood glucose levels (BGLs) accompanied by a series of complications. Exogenous insulin supplement is essential for both type I and advanced type II diabetics to manage blood glucose in their daily life. Thus insulin delivery has become a hot research topic and a lot of effort has been witnessed on the development of insulin delivery methods. Being like artificial pancreases, smart glucose-responsive insulin delivery systems that are able to automatically release insulin on-demanded according to the real-time BGLs are considered to be ideal alternatives to damaged islets and have significant potential for diabetes treatment. Therefore, this review is aimed to summarize the recent advances in the smart glucose-responsive insulin delivery systems, including microscopic or macroscopic systems based on the glucose oxidase (GOx), phenylboronic acid (PBA) and concanavalin A (Con A). From the point of view of materials science and engineering, preparation, properties and glucose response mechanism of different systems are introduced. Their advantages, challenges and opportunities are also discussed.