A general approach is reported to fabricate a stimuli responsive system via coassembly of diselenide-containing block copolymers with polymer lipids, which integrates the stimuli-responsiveness of diselenide chemistry and the biocompatibility of polymer lipids. By using dynamic light scattering, transmission electron microscopy, and zeta potential analyzer, coassembly behavior of these two kinds of polymers and responsiveness of coassemblies have been investigated. These coassemblies can exhibit redox-responsiveness inheriting from the diselenide-containing block copolymers. In the presence of low concentration of hydrogen peroxide or glutathione, the coassemblies can be disrupted.

Reactive oxygen species (ROS) play crucial roles in cell signaling and redox homeostasis and are strongly related to metabolic activities. The increase of the ROS concentration in organisms can result in several diseases, such as cardiovascular diseases and cancer. The concentration of ROS in biologically relevant conditions is typically as low as around tens of micromolars to 100 μM H2O2, which makes it necessary to develop ultrasensitive ROS-responsive systems. A general approach is reported here to fabricate an ultrasensitive ROS-responsive system via coassembly between tellurium-containing molecules and phospholipids, combining the ROS-responsiveness of tellurium and the biocompatibility of phospholipids. By using dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and NMR spectra, coassembly behaviors and the responsiveness of the coassemblies have been investigated. These coassemblies can respond to 100 μM H2O2, which is a biologically relevant ROS concentration, and demonstrate reversible redox properties.

Tellurium-containing photoresponsive polyelectrolyte multilayer films were fabricated by layer-by-layer assembly of a tellurium-containing polymer, photosensitizer, and poly(styrenesulfonate). The resulting films were investigated by UV/vis spectroscopy, XPS, EPR, and fluorescence spectroscopy. Under visible light, the photosensitizer in the film is excited and transforms triplet oxygen into singlet oxygen in aqueous solution. Singlet oxygen oxidizes -Te- to high valence state (Te═O) on the polymer backbone. The generated (Te═O) group makes the micelles more hydrophilic and looser, thereby facilitating the controlled release of the loaded cargo of micelles. These results show that the film has the potential to be used for cargo loading and controlled release, thus may provide a new way to combine photodynamic therapy and chemotherapy.

A degradable ROS responsive selenide-containing block polymer would undergo an oxidation-related elimination and degradation process.

A coordination-responsive tellurium containing film was fabricated for controlled release. The coordination chemistry between telluride molecules and cisplatin was utilized for the loading of cisplatin, while competitive ligands were used for triggered release. This work could enrich the coordination responsive system and further tune the release kinetics of cisplatin.