Development of glucose/pH responsive smart hydrogel of carbopol and application in microneedles

A new glucose-responsive polymer made from carbopol and 3-phenylboronic acid was developed with condensation reaction. The resulting polymer possesses a pKa of 6.86 ± 0.38 at a proper feedstock ratio of 1:2 (w/w), which approached the physiological pH. The hydrogel made of the corresponding polymer exhibited good features in response to changes of glucose concentration and solution pH value. The sensitive feature of glucose was elevated owing to the addition of ammoniated ZnO nanoparticles, and be related to the structure morphology of hydrogel converted into irregular sheet along with porous structure from initial regular lamellar. Two types of microneedles containing insulin were also made and demonstrated their enough piercing abilities by mechanical compression test. Transdermal release tests of insulin in vitro displayed well responsive release performances, and then the pulsatile releases ensued since glucose concentration alternated between 400 and 100 mg/dL, indicating that the developed micronedle system can realize the controlled release of insulin, i.e. the constructed smart carbopol polymer have potential application in the field of biomedicine.