Fabrication of Two-Dimensional Platelets with Heat-Resistant Luminescence and Large Two-Photon Absorption Cross Sections via Cooperative Solution/Solid Self-Assembly.

The combination of solution self-assembly, which enables primary morphological control, and solid self-assembly, which enables the creation of novel properties, can lead to the formation of new functional materials that cannot be obtained using either technique alone. Herein, we report a cooperative solution/solid self-assembly strategy to fabricate novel two-dimensional (2D) platelets. Precursor 2D platelets with preorganized packing structure, shape, and size are formed via the living self-assembly of a donor-acceptor fluorophore and volatile coformer (i.e., propanol) in solution phase. After high-temperature annealing, propanol is released from the precursor platelets, and new continuous intermolecular hydrogen bonds are formed. The new 2D platelets formed retain the controllable morphologies originally defined by the solution phase living self-assembly but exhibit remarkable heat-resistant luminescence up to 200 °C and high two-photon absorption cross sections (i.e., >19,000 GM at 760 nm laser excitation).

Development of Binary Coassemblies for Sensitively and Selectively Detecting Gaseous Sarin.

The low sensitivity and poor selectivity of fluorescence sensors for real gaseous sarin detection greatly hinder their real-world applications. In this work, we report the development of a novel fluorophore with an active N-H vibration in the benzimidazole group for the sensitive detection of gaseous sarin. We demonstrate that the interactions between the nucleophilic fluorine atom in sarin and the electrophilic hydrogen atom in the benzimidazole group of the fluorophore can restrict the N-H vibration to yield sensitive fluorescence-enhancing responses. On the basis of this mechanism, the experimental and theoretical limits of detection for gaseous sarin can reach as low as 50 and 4.8 ppb, respectively. We further coassemble this fluorophore with another two D-A fluorophores containing different acceptor groups and use the resulting coassemblies as sensor array members to obtain access to differential combined responses to gaseous sarin compared with various interferents, including diethylchlorophosphate and acids. This two-member sensor array proves to be capable of detecting trace sarin in complex environments, demonstrating its potential applications in the real world.

Rare case report and literature review of intracranial mesenchymal chondrosarcoma.

Intracranial mesenchymal chondrosarcoma (IMC) is a rare primary malignant tumor in the skull, but mostly originates from the abnormal residual chondrocytes in the embryonic period, which grow slowly, and primarily occurs at the junction of the cartilage of the skull base. IMC is difficult to diagnose by preoperative imaging and is easily misdiagnosed. It needs to be differentiated from meningiomas, gliomas, hemangioma, fibroids, etc.; this article introduces a case of primary IMC in a 38-year-old female teacher, and reviews the literature on the diagnosis and treatment of symptoms. The patient suffered from persistent severe headaches without nausea and vomiting. There was no obvious abnormality in the physical examination. Magnetic resonance imaging (MRI) of the head showed a circular space-occupying lesion on the right frontal bone and forehead; the mass was approximately 5.9 cm × 5.2 cm × 5.5 cm, and there was a large edema band surrounding it. The space-occupying effect was obvious; bilateral ventricles were compressed, and on the right side, the midline structure was shifted to the left. The patient was initially diagnosed with simple meningioma. After admission, the right frontal lobe meningioma was resected under general anesthesia, and the tumor tissue was completely removed in blocks. The postoperative pathology report stated: malignant tumor of the right frontal lobe; consider mesenchymal chondrosarcoma. Following a difficult pathological consultation at the Provincial Medical Association, the tumor was found to be consistent with mesenchymal chondrosarcoma. Intracranial chondrosarcoma is a very rare malignant tumor. Other intracranial masses, such as meningioma and glioma, should be distinguished through differential diagnosis. At present, more attention is paid to surgical intervention and combined radiotherapy and chemotherapy for the treatment of IMC, which should also be the future treatment option.

Chemodynamic/photothermal synergistic therapy based on Ce-doped Cu-Al layered double hydroxides.

The combination of chemodynamic therapy (CDT) with photothermal therapy (PTT) is an efficacious strategy in cancer treatment to acquire satisfactory therapy efficiency in the endogenous redox reaction and external laser induction. In this work, we have designed Ce doped Cu-Al layered double hydroxide (CAC-LDH) ultrathin them through a bottom-up synthesis method, and further loaded them with indocyanine green (ICG). The synthesized ICG/CAC-LDH was used as a Fenton-catalyst and photothermal agent. With the Fenton activity, the ICG/CAC-LDH nanosheets could decompose H2O2 and exhibit a low KM value (1.57 mM) and an ultra-high Vmax (4.88 × 10-6 M s-1) value. Due to the presence of oxidized metal ions, ICG/CAC-LDH could induce intracellular GSH depletion and reduce Cu2+ and Ce4+ to Cu+ and Ce3+, respectively. The generated Cu+ and Ce3+ further reacted with local H2O2 to generate toxic hydroxyl radicals (˙OH) via the Fenton reaction. Owing to the obviously enhanced absorption of ICG/CAC-LDH at 808 nm, the photothermal efficiency of ICG/CAC-LDH increased significantly compared with ICG (ΔT = 34.7 °C vs. 28.3 °C). In vitro studies substantiate the remarkable CDT/PTT efficacy, with complete apoptosis of HepG2 cancer cells (the cell viability is less than 2%) treated with 25 µg mL-1 of ICG/CAC-LDH. Furthermore, ICG/CAC-LDH could also act as a contrast agent for cancer magnetic resonance imaging (MRI) and photoacoustic imaging (PAI). These results demonstrate the potential of ICG/CAC-LDH as an integrated agent for dual-modal imaging and synergistic CDT/PTT.

Multicomponent Transition Metal Dichalcogenide Nanosheets for Imaging-Guided Photothermal and Chemodynamic Therapy.

Transition metal dichalcogenides (TMDs) have received considerable attention due to their strong absorption in the near-infrared (NIR) region, strong spin-orbit coupling, and excellent photothermal conversion efficiency (PCE). Herein, CoFeMn dichalcogenide nanosheets (CFMS NSs) are prepared via facile vulcanization of a lamellar CoFeMn-layered double hydroxide (LDH) precursor followed by polyvinyl pyrrolidone modification (to give CFMS-PVP NSs), and found to show excellent photoacoustic (PA) imaging and synergistic photothermal/chemodynamic therapy (PTT/CDT) performance. The as-prepared CFMS-PVP NSs inherit the ultrathin morphology of the CoFeMn-LDH precursor and exhibit an outstanding photothermal performance with a η of 89.0%, the highest PCE reported to date for 2D TMD materials. Moreover, 50% of maximum catalytic activity (Michaelis-Menten constant, K m) is attained by CFMS-PVP NSs with 0.26 × 10-3 m H2O2 at 318 K, markedly lower than the endogenous concentration of H2O2 inside tumor cells. In addition, complete apoptosis of HepG2 cancer cells and complete tumor elimination in vivo are observed after treatment with CFMS-PVP NSs at a low dose, substantiating the NSs' remarkable PTT/CDT efficacy. This work provides a new and facile approach for the synthesis of high-quality multicomponent TMD nanosheets with precise process control, the potential for mass production, and outstanding performance, providing great promise in cancer theranostics.

Photoluminescence enhancement of silver nanoclusters assembled on the layered double hydroxides and their application to guanine detection.

Development of the fluorescent and stability-enhanced scheme for silver nanoclusters is challengeable. In the present study, silver nanoclusters stabilized by nuclear fast red sodium salt (NFR) were assembled with Mg2Al-layered double hydroxide (LDH) nanosheets. The as-prepared films (AgNCs-NFR/LDH UTFs) were confirmed by powder X-ray diffraction (XRD), UV-vis, fluorescence spectra,atomic force microscope (AFM) and scanning electron microscope (SEM). Owing to the confined effects of 2D layered LDH nanosheets, the fluorescence intensity and photostability of AgNCs-NFR/LDH UTFs have improved significantly in comparing with that of AgNCs-NFR solution. By introducing Cu2+ ions as a modulator, AgNCs-NFR/LDH UTFs were applied successfully to determination guanine in the concentration range of 10-20 µM and 20-100 µM. The limit of detection was 1.85 µM guanine. Moreover, the selectivity for guanine over the other nucleotide bases (such as adenine, thymine, cytosine and uracil) and some potential interfering substances were investigated. The constructed sensor films were simple and economic which avoided a sophisticated synthetic process, and the detected reactions completed within 5 min. Therefore, this paper provides a new opportunity for fabrication the nanocomposite sensor based on AgNCs-NFR/LDH for guanine sensing.

Fabrication of dual-stimuli responsive films assembled by flavin mononucleotide and layered double hydroxides.

A dual-stimuli responsive strategy is developed for the detection of melamine and temperature. Flavin mononucleotide (FMN) was immobilized onto layered double hydroxide (LDH) nanosheets through a layer-by-layer process. The as-prepared composite films show higher emission intensity, prolonged fluorescence lifetimes and fluorescence responses towards melamine and temperature.