Aptamer-functionalized in situ injectable hydrogel for controlled protein release

Various in situ injectable hydrogels have been developed for protein delivery in treating human diseases. However, most hydrogels are highly permeable, which can lead to the rapid release of loaded proteins. The purpose of this study is to apply nucleic acid aptamers to functionalize an in situ injectable hydrogel model to control the release of proteins. The aptamers were studied using secondary structural predictions and binding analyses. The results showed that the structural predictions were different from the experimental measurements in numerous cases. The affinity of the aptamer was significantly affected by the mutations of the essential nucleotides, whereas it was not significantly affected by the variations of the nonessential nucleotides. The mutated aptamers were then used to functionalize the injectable hydrogel model. The results showed that the aptamer-functionalized hydrogel could prolong protein release. Moreover, the release rates could be controlled by adjusting the affinity of the aptamer.