Radiocatalytic synthesis of acetic acid from CH4 and CO2.

The C-C coupling of methane (CH4) and carbon dioxide (CO2) to generate acetic acid (CH3COOH) represents a highly atom-efficient chemical conversion, fostering the comprehensive utilization of greenhouse gases. However, the inherent thermodynamic stability and kinetic inertness of CH4 and CO2 present obstacles to achieving efficient and selective conversion at room temperature. Our study reveals that hydroxyl radicals (·OH) and hydrated electrons (eaq-) produced by water radiolysis can effectively activate CH4 and CO2, yielding methyl radicals (·CH3) and carbon dioxide radicals (·CO2-) that facilitate the production of CH3COOH at ambient temperature. The introduction of radiation-synthesized CuO-anchored TiO2 bifunctional catalyst could further enhance reaction efficiency and selectivity remarkably by boosting radiation absorption and radical stability, resulting in a concentration of 7.1 mmol·L-1 of CH3COOH with near-unity selectivity (>95%). These findings offer valuable insights for catalyst design and implementation in radiation-induced chemical conversion.

An "AND" Logic-Gated Prodrug Micelle Locally Stimulates Antitumor Immunity.

Materials that can respond to multiple biomarkers simultaneously, acting as an "AND" gate, have the potential to enhance tumor-targeting for drug delivery. In this study, an "AND" logic-controlled release prodrug micelle is developed for codelivering the chemotherapeutic and the stimulator of interferon genes (STING) agonist, enabling precise combinatorial therapy. The drug release is programmed by tumor-enriched boramino acids (BAA) in the tumor microenvironment and intracellular reactive oxygen species (ROS), resulting in enhanced tumor targeting. STING agonist is successfully encapsulated into prodrug micelles through π-π stacking and hydrophobic interactions. These AND logic-gated prodrug micelles can achieve tumor-targeted delivery of STING agonist, leading to significantly enhanced immune activation and antitumor efficacy in vivo. It is expected that this clinically relevant nanoplatform will provide a rational design of an effective immunotherapy combination regimen to convert immunologically "cold" tumors to immunogenic "hot" tumors, addressing the major challenges faced by immunotherapies.

Desilylation Induced by Metal Fluoride Nanocrystals Enables Cleavage Chemistry In Vivo.

Metal fluoride nanocrystals are widely used in biomedical studies owing to their unique physicochemical properties. The release of metal ions and fluorides from nanocrystals is intrinsic due to the solubility equilibrium. It used to be considered as a drawback because it is related to the decomposition and defunction of metal fluoride nanocrystals. Many strategies have been developed to stabilize the nanocrystals, and the equilibrium concentrations of fluoride are often <1 mM. Here we make good use of this minimum amount of fluoride and unveil that metal fluoride nanocrystals could effectively induce desilylation cleavage chemistry, enabling controlled release of fluorophores and drug molecules in test tubes, living cells, and tumor-bearing mice. Biocompatible PEG (polyethylene glycol)-coated CaF2 nanocrystals have been prepared to assay the efficiency of desilylation-induced controlled release of functional molecules. We apply the strategy to a prodrug activation of monomethyl auristatin E (MMAE), showing a remarkable anticancer effect, while side effects are almost negligible. In conclusion, this desilylation-induced cleavage chemistry avails the drawback on empowering metal fluoride nanocrystals with a new function of perturbing or activating for further biological applications.