Magnetic two-dimensional nanocomposites for multimodal antitumor therapy: a recent review.

Magnetic two-dimensional nanocomposites (M2D NCs) that synergistically combine magnetic nanomedicine and 2D nanomaterials have emerged in multimodal antitumor therapy, attracting great interest in materials science and biomedical engineering. This review provides a summary of the recent advances of M2D NCs and their multimodal antitumor applications. We first introduce the design and fabrication of M2D NCs, followed by discussing new types of M2D NCs that have been recently reported. Then, a detailed analysis and discussions about the different types of M2D NCs are presented based on the structural categories of 2D NMs, including 2D graphene, transition metal dichalcogenides (TMDs), transition metal carbides/nitrides/carbonitrides (MXenes), black phosphorus (BP), layered double hydroxides (LDHs), metal organic frameworks (MOFs), covalent organic frameworks (COFs) and other 2D nanomaterials. In particular, we focus on the synthesis strategies, magnetic or optical responsive performance, and the versatile antitumor applications, which include magnetic hyperthermia therapy (MHT), photothermal therapy (PTT), photodynamic therapy (PDT), drug delivery, immunotherapy and multimodal imaging. We conclude the review by proposing future developments with an emphasis on the mass production and biodegradation mechanism of the M2D NCs. This work is expected to provide a comprehensive overview to researchers and engineers who are interested in such a research field and promote the clinical translation of M2D NCs in practical applications.

Unique BiFeO3/g-C3N4 mushroom heterojunction with photocatalytic antibacterial and wound therapeutic activity.

Bacterial infections have become a major problem threatening public health, and it is of great significance to treat wound infections in biological systems caused by bacteria. However, traditionally used bacteriostatic agents usually cause additional pollution. Herein a mushroom-shaped clean and Green BiFeO3/g-C3N4 composite is employed for the first time for photocatalytic antibacterial activity and for the further promotion of wound healing. The ratio between BiFeO3 and g-C3N4 was delicately regulated to control the generated amount of ˙OH and ˙O2- by catalyzing the decomposition of hydrogen peroxide (H2O2) under illumination. Results show that 10%BFO/CN demonstrates the best performance for ˙OH and ˙O2- production, resulting in the highest antibacterial ability against E. coli and S. aureus. In addition, the catalytic mechanism of BiFeO3/g-C3N4 towards antibacterial activity is disclosed by a combination of ESR monitoring and analysis of the Mott-Schottky diagram. Furthermore, in vivo experiments prove that 10%BFO/CN can effectively promote anti-infection and wound healing in nude mice. This work sheds deep scientific insight on the synergistic effect of photocatalysis and photo-Fenton degradation as well as their application in antibacterial and wound therapeutic activity.

Highly stable branched cationic polymer-functionalized black phosphorus electrochemical sensor for fast and direct ultratrace detection of copper ion.

Copper ions (Cu2+) is an indispensable trace element in the process of metabolism and intake of excessive Cu2+ may lead to fatal diseases such as Alzheimer's disease. It is highly demanding to develop a sensitive, selective and convenient method for Cu2+ detection. In this work, thin-layer structured polyethyleneimine (PEI) decorated black phosphorus (BP) nanocomposite is one-step synthesized for an electrochemical sensor toward direct detection of Cu2+. This sensor achieves a wide detection range of 0.25-177 µM, a low detection limit of 0.02 µM much below the Environmental Protection Agency (EPA) maximum contaminant levels for drinking water (20 µM for Cu2+), and much faster response (1.5 s response time) and simpler operation than the conventional tedious anodic stripping voltammetry, ranking one of the best among all reported Cu2+ sensor. The great sensing enhancement is mainly due to a synergistic effect of BP and PEI of the composite, of which the former offers the reactivity while the latter splits the thick BP to thin-layer structured PEI-BP composite for larger reaction area. Meanwhile, a flexible sensor has been successfully fabricated and applied in detecting of Cu2+ in real samples of river, confirming the application feasibility of PEI-BP sensor in water environment control.

Co-delivery of chlorin e6 and doxorubicin using PEGylated hollow nanocapsules for 'all-in-one' tumor theranostics.

Aim: Hollow mesoporous copper sulfide nanocapsules conjugated with poly(ethylene glycol) (PEG), doxorubicin and chlorin e6 (HPDC) were synthesized for fluorescence imaging and multimodal tumor therapy. Materials & methods: HPDC were synthesized by encapsulating chlorin e6 and doxorubicin into PEGylated nanocapsules via a simple precipitation method. The photothermal/photodynamic effects, drug release, cellular uptake, imaging capacities and antitumor effects of the HPDCs were evaluated. Results: This smart nanoplatform is stimulus-responsive toward an acidic microenvironment and near infrared laser irradiation. Moreover, fluorescence imaging-guided and combined photothermal/photodynamic/chemotherapies of tumors were promoted under laser activation and led to efficient tumor ablation, as evidenced by exploring animal models in vivo. Conclusion: HPDCs are expected to serve as potent and reliable nanoagents for achieving superior therapeutic outcomes in cancer management.

Enhanced Photoacoustic and Photothermal Effect of Functionalized Polypyrrole Nanoparticles for Near-Infrared Theranostic Treatment of Tumor.

Functionalized nanomaterials with near-infrared (NIR) responsive capacity are quite promising for theranostic treatment of tumors, but formation of NIR responsive nanomaterials with enhanced theranostic ability and excellent biocompatibility is still very challenging. Herein, PEGylated indocyanine green (ICG)-loaded polypyrrole nanoparticles (PPI NPs) were designed and successfully formed through selecting polydopamine as the linkage between each component, demonstrating enhanced NIR responsive theranostic ability against tumor. By combining in vitro cell study with in vivo assay, the formed PPI NPs were proven to be fantastically biocompatible while effectively internalization in HeLa cells and retention in HeLa tumor were demonstrated by in vitro flow cytometry/confocal measurement and in vivo photoacoustic imaging assay. With the guidance of photoacoustic imaging, successful photothermal ablation of tumor was achieved by treatment with PPI NPs plus laser, which was much more effective than the group treated with NPs free of ICG. The combined enhanced photoacoustic and photothermal effect is mainly ascribed to the functionalized polypyrrole nanoparticles, which could accumulate in the tumor site more effectively with a relatively longer retention time taking advantage of the nanomaterial-induced endothelial leakiness phenomenon. All these results demonstrating that this designed PPI NPs possessing enhanced NIR responsive property hold great promise for tumor NIR theranostic applications.

PEGylated magnetic Prussian blue nanoparticles asa multifunctional therapeutic agent for combined targeted photothermal ablation and pH-triggered chemotherapy of tumour cells.

Multifunctional nanoagents have become popular and valuable pharmaceuticals for effective cancer treatment. Moreover, there is an increasing tendency to develop therapeutic agents with excellent biocompatibility, high efficiency, specific targeting and combinatorial treatment effects. In this study, we proposed a facile technique to synthesize PEGylated (polyethylene glycol modified) magnetic Prussian blue (PB) nanoparticles with encapsulated doxorubicin (DOX), abbreviated as Fe3O4@PB/PEG/DOX NPs, for combined targeted photothermal ablation and pH-triggered chemotherapy of tumour cells. The PEGylation of Fe3O4@PB core-shell structure was achieved through a thin-film hydration process; DOX was loaded into the nanocapsule via hydrophobic interactions. An in vitro study indicated increased drug release under acidic conditions, mimicking mild acidic tumour microenvironments. Additionally, the nanocomposites exhibited superparamagnetism, contributing to an improved therapeutic effect guided by a localized magnetic field. Cytotoxicity studies demonstrated outstanding photothermal-chemotherapy combinatorial effects on HeLa cells, attributed to the targeted photothermic effect mediated by the pH-triggered cellular uptake of DOX. Specifically, the viability of HeLa cells decreased to 8.5% after treatment with the nanoagent (DOX=10µgmL-1) and near infrared irradiation, indicating an evident tumour inhibition effect in vitro. This study presented a nanoplatform for efficient and targeted cancer treatment, which may lead to the development of multifunctional nanodrug vehicles for cancer therapy.

Two dimensional atomically thin MoS2 nanosheets and their sensing applications.

The extraordinary properties of layered graphene and its successful applications in electronics, sensors, and energy devices have inspired and renewed interest in other two-dimensional (2D) layered materials. Particularly, a semiconducting analogue of graphene, molybdenum disulfide (MoS2), has attracted huge attention in the last few years. With efforts in exfoliation and synthetic techniques, atomically thin films of MoS2 (single- and few-layer) have been recently prepared and characterized. 2D MoS2 nanosheets have properties that are distinct and complementary to those of graphene, making it more appealing for various applications. Unlike graphene with an indirect bandgap, the direct bandgap of single-layer MoS2 results in better semiconductor behavior as well as photoluminescence, suggesting its great suitability for electronic and optoelectronic applications. Compared to their applications in energy storage and optoelectronic devices, the use of MoS2 nanosheets as a sensing platform, especially for biosensing, is still largely unexplored. Here, we present a review of the preparation of 2D atomically thin MoS2 nanosheets, with an emphasis on their use in various sensing applications.

[Effects of electro-acupuncture on neuronal apoptosis and associative function in rats with spinal cord injury].

OBJECTIVE: To explore the effect of electro-acupuncture to improve the bladder function after acute spinal cord injury in rats and its possible mechanism. METHODS: Sixty healthy adult male SD rats of SPF grade, with body weight of 220 to 250 g, one week after feeding adaptation, were randomly divided into sham operation group, model group, electro-acupuncture group, electro-acupuncture control group with 15 rats in each group. Sham operation group underwent no stimulation, and the moderate damage model of spinal cord injury were made in other three groups according to modified Allens method. The model group were not treated, electro-acupuncture group were treated with electro-acupuncture on Zhibianxue and Shuidaoxue, and electro-acupuncture control group were treated with electro-acupuncture on 0.5 inch next to Zhibianxue and Shuidaoxue. The frequency of 2/100 Hz, current of 1 mA, stimulation time of 15 min, once a day, left and right alternately stimulate every time, for a total of 7 times. The changes of residual urine volume and urine output in rats at the 1st and the 7th days after operation were observed. And 7 d later, the rats were sacrificed and the injured spinal cord were taken out to observe the apoptosis, and to detect the changes of Bcl-2, Bax, Bad content. RESULTS: After modeling,the rats of three groups showed different bladder dysfunction. In electro-acupuncture group and electro-acupuncture control group, the residual urine volume of the 7th day after operation was significant lower than the 1st day after operation (P < 0.001), and there was statistically significant difference on the 7th day after operation between two groups (P < 0.001). Compared with model group, the urine output of electro-acupuncture group and electro-acupuncture control group was significantly increased on the 7th day after operation, and there was sig- nificant difference between electro-acupuncture group and electro-acupuncture control group (P < 0.001). Electro-acupuncture can inhibit apoptosis of spinal cord neurons by TUNEL detection. Postoperative at 7 d, the rate of nerve cell apoptosis in electro -acupuncture group and electro-acupuncture control group was significant increased than model group (P < 0.01, P < 0.05), and there was significant difference between electro-acupuncture group and electro-acupuncture control group (P < 0.005). Compared with model group, the positive expression rate of Bax, Bad decreased (P < 0.01, P < 0.05), and Bcl-2 increased (P < 0.01) in electro-acupuncture group and electro-acupuncture control group,there was significant difference between electro-acupuncture group and electro-acupuncture control group (P < 0.01). CONCLUSION: Electro-acupuncture can obviously promote the repair of acute spinal cord injury,its mechanism may be through increasing Bcl-2, inhibiting the expression of Bax, Bad, which inhibits the apoptosis of spinal cord neurons.

Nitrogen-enriched carbon sheets derived from egg white by using expanded perlite template and its high-performance supercapacitors.

Nitrogen-enriched carbon sheets were synthesized using egg white as a unique carbon source and expanded perlite as a novel template. The as-prepared material was further used as an electrode material for super capacitor applications, demonstrating excellent super capacitance with a maximum gravimetric specific capacitance of 302 F g(−1) at 0.5 A g(−1) in a 3-electrode setup for a sample carbonized at 850 °C and activated for 6 h. Moreover, the carbon sheet-based capacitor with 2-symmetric electrodes showed an excellent cycle life (2% loss at 0.1 A g(−1) after 10 000 cycles). The excellent performance may be attributed to the combination of the 3D carbon structure and the highly concentrated doped nitrogen component from the natural egg source for superior pseudocapacitance.