Stimuli‐responsive chitosan (CS) hydrogels exhibit great potential for drug delivery and tissue engineering; however, the structure of these stimuli‐responsive CS hydrogels, such as dual pH‐ and thermo‐responsive hydrogels, is difficult to control or needs additional crosslinking agents. Here, a new dual pH‐ and thermo‐responsive hydrogel system is developed by combining pH‐responsive C6‐OH allyl‐modified CS (OAL‐CS) with thermo‐responsive poly(N‐isopropylacrylamide) (PNIPAM). The thiol groups in PNIPAM and the allyl groups in OAL‐CS can rapidly form crosslinking hydrogel network by “thiol‐ene” click chemistry under UV irradiation. As expected, the swelling ratio of the OAL‐CS/PNIPAM hydrogel can be controlled by changing pH and temperature. Moreover, the hydrogel displays non‐cytotoxic nature toward human bone marrow mesenchymal stem cells, and the histological analyses reveal the subcutaneous tissue with no signs of inflammation after 5 days of injection in vivo. The results indicate that the new OAL‐CS/PNIPAM hydrogel has potential to serve as a smart injectable platform for application in drug delivery and tissue engineering.
A novel diarylethene with a triazole-linked rhodamine B unit has been synthesized by click chemistry. When triggered by light, proton, and metal ions, the diarylethene can be used as a fluorescence switch, leading to a multiaddressable system. The diarylethene shows sequencedependent responses through efficient interaction of the specific triazole-linked rhodamine B unit with proton and metal ions. Furthermore, the diarylethene can serve as a nakedeye chemosensor for highly selective recognition of different metal ions in different solvent systems. The diarylethene was highly selective toward Al 3+ with remarkable fluorescence change from dark to yellow in acetonitrile, while it selectively recognized Cu 2+ with significant fluorescence change from dark to bright yellow in the mixture of acetonitrile and water (v/v = 4/6). Finally, a logic circuit was constructed with the unimolecular platform by using the combinational stimuli of light and chemical species as inputs and the fluorescence intensity at 595 nm as output.
A FRET-based colorimetric and ratiometric coumarin–rhodamine B fluorescent sensor was designed, and its sensing behaviors for sequentially detecting Cu2+ and arginine were studied systematically.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.