Mechanism investigation on the solid-solid phase transition of CL-20 induced by water vapor.

Energetic materials often possess different polymorphs that exhibit distinguishable performances. As a typical energetic material, hexanitrohexaazaisowurtzitane (CL-20 or HNIW) is one of the most powerful explosives nowadays. Phase transition of CL-20 induced by ubiquitous water vapor leading to an increase in sensitivity and a decrease in energy level is a key bottleneck that limits the widespread application of CL-20-based explosives.

Synthesis and DNA Cleavage Activity of Cationic Methylene-Blue-Backboned Polymers.

Methods of DNA cleavage have broad bioapplications in gene editing, disease treatment, and biosensor design. The traditional method for DNA cleavage is mainly through oxidation or hydrolysis mediated by small molecules or transition metal complexes. However, DNA cleavage by artificial nucleases using organic polymers has been rarely reported.

Intrinsic Mitochondrial Reactive Oxygen Species (ROS) Activate the In Situ Synthesis of Trimethine Cyanines in Cancer Cells.

Environment-responsive in situ synthesis of molecular fluorescent dyes is challenging. Herein, we develop a photoextension strategy to make trimethine cyanines with decent conversion efficiency (up to 81 %) using 1-butyl 2,3,3-trimethyl 3H-indole derivatives as the sole precursors, and demonstrate a free radical mechanism. In the inducer-extension stage, free radicals and reactive oxygen species (ROS) were able to mediate similar reactions with no assistance of light.

One pot synthesis and self-assembly of methylene blue-backboned polymers.

Studies of methylene blue-backboned polymers (MBPs) are hindered by the limited availability of polymerization methods. Herein, we developed an oxidative polymerization method to produce MBPs. The polymerization is performed in aqueous medium, and is organic solvent-free, heavy metal-free, time-efficient (on a timescale of minutes), and does not need pre-formed methylene blue chromophores.

Cascade Reactions by Nitric Oxide and Hydrogen Radical for Anti-Hypoxia Photodynamic Therapy Using an Activatable Photosensitizer.

Organelle-targeted activatable photosensitizers are attractive to improve the specificity and controllability of photodynamic therapy (PDT), however, they suffer from a big problem in the photoactivity under both normoxia and hypoxia due to the limited diversity of phototoxic species (mainly reactive oxygen species). Herein, by effectively photocaging a π-conjugated donor-acceptor (D-A) structure with an N-nitrosamine substituent, we established a unimolecular glutathione and light coactivatable photosensitizer, which achieved its high performance PDT effect by targeting mitochondria through both type I and type II (dual type) reactions as well as secondary radicals-participating reactions. Of peculiar interest, hydrogen radical (H) was detected by electron spin resonance technique.

GSH and H O Co-Activatable Mitochondria-Targeted Photodynamic Therapy under Normoxia and Hypoxia.

Currently, photosensitizers (PSs) that are microenvironment responsive and hypoxia active are scarcely available and urgently desired for antitumor photodynamic therapy (PDT). Presented herein is the design of a redox stimuli activatable metal-free photosensitizer (aPS), also functioning as a pre-photosensitizer as it is converted to a PS by the mutual presence of glutathione (GSH) and hydrogen peroxide (H O ) with high specificity on a basis of domino reactions on the benzothiadiazole ring. Superior to traditional PSs, the activated aPS contributed to efficient generation of reactive oxygen species including singlet oxygen and superoxide ion through both type 1 and type 2 pathways, alleviating the aerobic requirement for PDT.

A photosynthesis-inspired supramolecular system: caging photosensitizer and photocatalyst in apoferritin.

Inspired by the bioinorganic structure of natural [FeFe]-hydrogenase ([FeFe]-Hase) that possesses iron sulfur clusters to catalyze proton reduction to hydrogen (H), we design a supramolecular photosystem by sequentially integrating hydrophobic ruthenium complex (as a photosensitizer) and diiron dithiolate complex (as a photocatalyst) into the inner surface or cavity of apoferritin via noncovalent interactions. This platform allows photosensitizer and catalyst to localize in a close proximity and short-distance electron transfer process to occur within a confined space. The resulted uniform core-shell nanocomposites were stable and well dispersed in water, and showed enhanced H generation activity in acidic solution as compared to the homogenous system without apoferritin participation.