Defect-Rich Ni–CoO@PEG Porous Hexagonal Nanosheets: Multi-enzyme and Ultrasound Catalysis for Synergistic Anticancer Treatment

Given the similarity with photocatalysis, sonodynamic therapy (SDT) can be defined as ultrasonic (US) catalysis. Encouraged by the principles of photocatalysis and defect chemistry, defect-rich nickel (Ni)-doped cobaltous oxide (Ni–CoO@PEG) porous hexagonal nanosheets have been synthesized as a sonosensitizer. The doping of Ni decreases the band gap that is testified by density functional theory to increase the US-generated charges. Under US irradiation, Ni–CoO@PEG nanosheets produce 1O2 as an active species that is determined by dissolved O2 and electrons. Moreover, the doping also brings abundant oxygen vacancies (OV) that not only are in favor of efficient separation of electron–hole but also enhance the interaction toward O2, boosting 1O2 generation. In addition, Ni–CoO@PEG shows robust mimic catalase (CAT) and peroxidase characterization to effectively improve the intratumor O2 content and oxidation stress. What is more, the nanosheets also possess glucose oxidase activity that can consume glucose to elevate the H2O2/acid level and to block the intracellular energy supply. The tandem nanozyme behaviors would further regulate the tumor microenvironment for assisting anticancer treatment. It is noted that Ni–CoO@PEG reveals a novel half-metallic feature endowing great magnetism and magnetic resonance imaging capacity. The above synergistic treatments exhibit outstanding anticancer performance that also evokes antitumor immunity to suppress metastasis and recurrence, efficiently

Synthesis of Benzofused Five-Ring Sultams via Rh-Catalyzed C–H Olefination Directed by an <i>N</i>‑Ac-Substituted Sulfonamide Group

A Rh-catalyzed <i>N</i>-Ac-sulfonamide group directed C–H olefination–cyclization to afford benzofused five-ring sultam is described with high yield and a wide range of substrate scope. The <i>N</i>-acetyl group is a key for this transformation implying that N–H acidity is the major influence. The acetyl group is removed under mild conditions in excellent yield to provide <i>NH</i>-free sultam that can be transformed into various benzofused five-ring sultam analogues via acylation, nucleophilic substitution, and Mitsunobu alkylation

An Enzyme-Responsive Controlled Release System of Mesoporous Silica Coated with Konjac Oligosaccharide

A simple and green method to fabricate an ingenious enzyme-responsive drug controlled release system was presented. Mesoporous silica material (mSiO₂) 100 nm in size was used as the host, and Konjac oligosaccharide (KOGC) was employed to seal the nanopores of mSiO₂ to inhibit the drug release. Rhodamine B was used as the model cargo to reveal the release behavior of the system. The KOGC-modified mSiO₂ (mSiO₂@KOGC) retains the drug until it reaches the colonic environment where bacteria secrete enzymes (β-mannanase) can degrade KOGC and make drug release. The amount of KOGC and enzyme can be used to adjust the release performance. And all the release behaviors fit the two-step Higuchi model, which predominate by KOGC degradation and mesoporous structure, respectively. With well bioactivity and selectivity, the system has potential application as an oral medicine carrier for treating intestinal disease

Hierarchical SnO₂ Nanostructures Made of Intermingled Ultrathin Nanosheets for Environmental Remediation, Smart Gas Sensor, and Supercapacitor Applications

In this paper, the hierarchical SnO2 nanostructures (HTNs) were prepared by a facile hydrothermal process. The prepared HTNs were characterized in detail by various analytical techniques that reveal the well-crystallinity with tetragonal rutile structure of SnO2 for the as-prepared material. By detailed experiments, interestingly, it was observed that the shapes and sizes of as-prepared HTNs could be tailored by varying the precursor concentration and reaction time. The synthesized HTNs were used as the efficient photocatalysts for the photocatalytic degradation of methylene blue (MB) under light illumination which showed almost complete degradation (∼99%) of MB dye in 20 min. The observed degradation for MB dye was higher than other commonly used dyes, i.e. methyl orange (MO; 96% in 50 min) and Rhodamine B (RhB; 97% in 40 min.). Further, the prepared HTNs were used as the effective gas sensing material to examine a series of volatile gases, such as ethanol, ammonia, benzene, acetone, toluene, methanol, diethyl ether, and methanol. By the detailed experiments, it was observed that the prepared HTNs exhibited tremendous gas sensing performance toward ethanol. Finally, because of the unique morphology and the fast ion and electron transfer characteristics, the prepared HTNs show excellent supercapacitor performances

pH-Responsive Magnetic Core–Shell Nanocomposites for Drug Delivery

Polymer-modified nanoparticles, which can load anticancer drugs such as doxorubicin (DOX), showing the release in response to a specific trigger, have been paid much attention in cancer therapy. In our study, a pH-sensitive drug-delivery system consisting of Fe3O4@mSiO2 core–shell nanocomposite (about 65 nm) and a β-thiopropionate-poly­(ethylene glycol) “gatekeeper” (P2) has been successfully synthesized as a drug carrier (Fe3O4@mSiO2@P2). Because of the hydrolysis of the β-thiopropionate linker under mildly acidic conditions, Fe3O4@mSiO2@P2 shows a pH-sensitive release performance based on the slight difference between a tumor (weakly acid) and normal tissue (weakly alkaline). And before reaching the tumor site, the drug-delivery system shows good drug retention. Notably, the nanocomposites are quickly taken up by HeLa cells due to their small particle size and the poly­(ethylene glycol) modification, which is significant for increasing the drug efficiency as well as the cancer therapy of the drug vehicles. The excellent biocompatibility and selective release performance of the nanocomposites combined with the magnetic targeted ability are expected to be promising in the potential application of cancer treatment

Porous Molybdenum Nitride Nanosphere as Carrier-Free and Efficient Nitric Oxide Donor for Synergistic Nitric Oxide and Chemo/Sonodynamic Therapy

Given its abundant physiological functions, nitric oxide (NO) has attracted much attention as a cancer therapy. The sensitive release and great supply capacity are significant indicators of NO donors and their performance. Here, a transition metal nitride (TMN) MoN@PEG is adopted as an efficient NO donor. The release process starts with H+-triggered denitrogen owing to the high electronegativity of the N atom and weak Mo–N bond. Then, these active NHx are oxidized by O2 and other reactive oxygen species (ROS) to form NO, endowing specific release to the tumor microenvironment (TME). With a porous nanosphere structure (80 nm), MoN@PEG does not require an extra carrier for NO delivery, contributing to ultrahigh atomic utilization for outstanding release ability (94.1 ± 5.6 μM). In addition, it can also serve as a peroxidase and sonosensitizer for anticancer treatment. To further improve the charge separation, MoN-Pt@PEG was prepared to enhance the sonodynamic therapy (SDT) effect. Accordingly, ultrasound (US) further promotes NO generation due to more ROS generation, facilitating in situ peroxynitrite (·ONOO–) generation with great cytotoxicity. At the same time, the nanostructure also degrades gradually, leading to high elimination (94.6%) via feces and urine within 14-day. The synergistic NO and chemo-/sono-dynamic therapy brings prominent antitumor efficiency and further activates the immune response to inhibit metastasis and recurrence. This work develops a family of NO donors that would further widen the application of NO therapy in other fields

Constructing Heteroatom-Doped Transition-Metal Sulfide Heterostructures for Hydrogen Evolution Reaction

Transition-metal sulfide (TMS) has been regarded as the most promising alternative to construct non-noble metal catalysts in the electrochemical hydrogen evolution reaction (HER). The excellent edge activation of MoS2 and abundant catalytic active sites of Ce2S3 can be utilized as the premise of constructing heterogeneous materials for electrochemical applications. Afterward, the heteroatoms (C, N, O, and Na) have been introduced to increase the original number of active sites (the number of the S–Mo–S on the edge molecular layer of MoS2 and exposed metal active center of Ce2S3). Additionally, the heterostructure of HAs@MoS2/Ce2S3 and ordered/amorphous carbon can enhance the activity by creating defects and localized disorder fields and accelerating the charge separation/transfer from cerium (Ce) sites to molybdenum (Mo) sites. Combining the above advantages, HAs@MoS2/Ce2S3 shows promising properties toward HER not only in acidic environments with a low overpotential (147.0 mV) but also in alkaline (160.5 mV) environments

Heterophase-Structured Cobalt Hydroxide on Partly Reduced Graphene Oxide for Enhanced Dopamine Biosensing

A hetero-phase structure of cobalt hydroxide [α/β-Co(OH)2] in situ formed with the partly reduced graphene oxide [Co(OH)2/PRGO] has been fabricated by a coprecipitation method. Depending on the interactions (nucleation, bonding with oxygen-rich groups, and partial conversion of GO into rGO) provided by GO, cobalt ions utilized the interactions under alkaline conditions provided by 2-methylimidazole to form hetero-phase α/β-Co(OH)2 and maintain the unstable-structure [α-Co(OH)2]. Beneficial to the large electrochemical active surface, rich redox active sites, and electronic transfer capability derived from hetero-phase structure [α/β-Co(OH)2] and the partly reduced graphene oxide, the Co(OH)2/PRGO has an extraordinary detection performance of DA: a multi-section continuous detection range (0.1 nM to 450 μM), a ultra-low limit of detection (0.078 nM, S/N = 3), and a strong anti-interference ability, coupled with an application potential in biological foods (pork) and in the body environment (serum)