Regulated immobilization of proteins on hydrogels allows for the creation of highly controlled microenvironments to meet the special requirements of cell biology and tissue engineering devices. Light is an ideal stimulus to regulate immobilization because it can be controlled in time, space, and intensity. Here, a photoresponsive hydrogel that enables the patterning of proteins by a combination of electrostatic adsorption and photoregulated charge change on a hydrogel is developed. It is based on a photosensitive cationic monomer (CLA), a coumarin caged lysine betaine zwitterion, incorporated into a polyvinylpyrrolidone (PVP) hydrogel, which can controllably change the charge from an adhesive positive state to an anti-adhesive zwitterion state upon irradiation at 365 nm. With this strategy, the immobilization of proteins is regulated and cell adhesion is programmed on hydrogels on demand. This approach should open up new avenues for hydrogels in biomedical applications.

Inspired by the critical role of ion channel proteins in the regulation of cellular activities, here we developed a new type of synthetic ion channel by simple benzocrown ether-based derivatives M1 and M2, where M1 had a dodecyl tail and M2 had a diethylene glycol-conjugated dodecyl tail. Being amphiphilic in nature, the two small molecules were assumed to form crown ether channels through supramolecular interactions in bilayer lipid membranes (BLMs). The efficient ion transport was investigated by both a fluorescence-based vesicle assay and a planar bilayer conductance measurement, and M2 with diethylene glycol substitution exhibited more efficient activity comparable to amphotericin B. Moreover, the presence of a photosensitive o-nitrobenzyl group provided the light-regulation to deactivate ion transport by destroying the channel assembly of the molecules in BLMs, which provides new opportunities for developing intelligent light-regulated systems for biomedical applications based on synthetic small molecules.

A facile methodology for light-triggered release of thiols under mild conditions is presented, which can be utilized for in situ bioconjugation with protein and quantum dot nanoparticles (QDs) efficiently.

Synthetic ion channels arise great interest due to their ability to mimic the biological functions of natural ion channels. Although a number of synthetic ion channels have been reported and have displayed biomedical applications, the design criteria for efficient synthetic ion channels remain essentially obscure. According to the structure framework of our previously prepared synthetic ion channel (compound 1), in this study, a series of amphiphilic small molecules (compounds 2, 3a–3b, 4a–4c and 5) with structural simplicity were designed to explore the relationship between the molecular structure and the transport activity in this system. By adjusting the substituted functional moieties in the four building blocks, it was concluded that appropriate supramolecular interactions and reasonable water solubility favored improvement of the transport activity of the channels. Finally, compound 6 with an optimized structure was prepared using favorable crown ether, amide, diethylene glycol-substituted benzene, and dodecyl hydrophobic moieties as building blocks. This compound exhibited efficient channel transport with significantly improved transport activity, in which the EC50 value was 3 times lower than that of compound 1. These results provide some useful experience for developing excellent synthetic ion channels based on artful regulation on the structures of facially synthetic small molecules.

In this study, a reductively cleavable photoreactive linker, disulfide-phenylazide (SPA), was synthesized and used to functionalize inorganic mesoporous silica nanoparticles (MSNs) by simple amidation reaction. Changed zeta potential, FT-IR and UV-vis or fluorescence spectra confirmed the successful photo-responsive functionalization of dextran (DSPA-MSNs) and immobilization of model avidin protein (ASPA-MSNs). With treatment by reducing agents, both DSPA-MSNs (with 10 mM DTT) and ASPA-MSNs (with 10 mM GSH) exhibited the reductive-responsive controllable release of coumarin 460 and bioactive protein. These results implied that the designed photo-affinity functional agent SPA with reductive-responsive cleavage provided a promising method to functionalize inorganic nanoparticles to improve their biocompatibility and biomedical applications.

Light-regulated ion channel-transport across lipid bilayers was realized using structurally simple azobenzene-based amphiphilic small molecules. UV or visible irradiation triggers molecular photoisomerization, which induces structural and membrane affinity changes in self-assembled channels, thus resulting in light-regulated ion transmembrane transport.

A novel covalently dexamethasone-conjugated drug release system based on cross-linked vegetable oil (DEX-CVs) was designed and prepared by simple curing reaction of modified vegetable oil and dexamethasone phosphomonoester (DEX-P) without any toxic catalyst and initiator. UV and HPLC analysis confirmed that the dexamethasone (DEX) drug could be released linearly with high purity by adjusting the component ratios. The analysis of the model reaction indicated that DEX-P in the optimized DEX-CV (A4) was mainly covalently conjugated in the cross-linked vegetable oil network by cyclic phosphotriester bond, and the selective hydrolysis induced the pure release of dexamethasone drug. Finally, the low cytotoxicity and successful osteogenic differentiation effect of A4 on human bone marrow mesenchymal stem cells (hBMSCs) was corroborated by the detection of MTT analysis, ALP activity, staining experiments and some gene expressions, which provided the promising applications in drug release areas and bone tissue engineering.

Two types of photocleavable crosslinkers (CLA and CLB) based on 7-amino coumarin moieties have been synthesized. The ingenious design for the crosslinkers with different vinyl functionalities was aimed to investigate the influence of the crosslinker’s structure on the photodegradation and photoswelling behavior of the constructed microgels. Analysis of DLS, UV spectra and fluorescence spectra verified the original intention and the generated microgels revealed structure-dependent photo-regulated swelling and degradation behavior. The successive loading and release of the hydrophobic Nile Red (NR) dye of the microgel upon visible light irradiation further showed its ability to be used as an excellent nanocarrier for hydrophobic compounds.

A new photo-controlled anticancer drug release system is reported based on the photo-induced electron transfer (PET) between semiconductor quantum dots (QDs) and N-methyl-4-picolinium (NAP) ester 1 under the excitation of visible light.

An excellent mesoporous silica nanoparticle (MSN) based drug deliver system (DDS) was reported for regulated anticancer drug release upon the irradiation of either one- or two-photon excitation. In this system, the coumarin grafted on MSN acted as both the “phototrigger” for the drug release and fluorescence group for cell luminescence imaging. External light manipulations such as changing irradiation wavelength, intensity, and time can regulate the release of the anticancer drug precisely. Biological studies in vitro suggest that the drug carrier can effectively deliver the anticancer drug into intracellular environs and, hence, promote the drug action to kill the cancer cells upon irradiation. We envision that the good biocompatibility, cellar uptake property, and efficient photoregulated drug release will be of great benefit to future controlled release in vivo biomedical applications.

A simple quantum-dot-based OFF–ON fluorescent probe is reported to detect glutathione with high selectivity and sensitivity from other structurally related thiols by a simple ligand displacement process.

In this study, a reductively cleavable photoreactive linker, disulfide-phenylazide (SPA), was synthesized and used to functionalize inorganic mesoporous silica nanoparticles (MSNs) by simple amidation reaction. Changed zeta potential, FT-IR and UV-vis or fluorescence spectra confirmed the successful photo-responsive functionalization of dextran (DSPA-MSNs) and immobilization of model avidin protein (ASPA-MSNs). With treatment by reducing agents, both DSPA-MSNs (with 10 mM DTT) and ASPA-MSNs (with 10 mM GSH) exhibited the reductive-responsive controllable release of coumarin 460 and bioactive protein. These results implied that the designed photo-affinity functional agent SPA with reductive-responsive cleavage provided a promising method to functionalize inorganic nanoparticles to improve their biocompatibility and biomedical applications.

Two types of photocleavable crosslinkers (CLA and CLB) based on 7-amino coumarin moieties have been synthesized. The ingenious design for the crosslinkers with different vinyl functionalities was aimed to investigate the influence of the crosslinker’s structure on the photodegradation and photoswelling behavior of the constructed microgels. Analysis of DLS, UV spectra and fluorescence spectra verified the original intention and the generated microgels revealed structure-dependent photo-regulated swelling and degradation behavior. The successive loading and release of the hydrophobic Nile Red (NR) dye of the microgel upon visible light irradiation further showed its ability to be used as an excellent nanocarrier for hydrophobic compounds.

A facile methodology for light-triggered release of thiols under mild conditions is presented, which can be utilized for in situ bioconjugation with protein and quantum dot nanoparticles (QDs) efficiently.

A new photo-controlled anticancer drug release system is reported based on the photo-induced electron transfer (PET) between semiconductor quantum dots (QDs) and N-methyl-4-picolinium (NAP) ester 1 under the excitation of visible light.

Light-regulated ion channel-transport across lipid bilayers was realized using structurally simple azobenzene-based amphiphilic small molecules. UV or visible irradiation triggers molecular photoisomerization, which induces structural and membrane affinity changes in self-assembled channels, thus resulting in light-regulated ion transmembrane transport.

A simple quantum-dot-based OFF–ON fluorescent probe is reported to detect glutathione with high selectivity and sensitivity from other structurally related thiols by a simple ligand displacement process.