Advance Progress in Assembly Mechanisms of Carrier-Free Nanodrugs for Cancer Treatment.

Nanocarriers have been widely studied and applied in the field of cancer treatment. However, conventional nanocarriers still suffer from complicated preparation processes, low drug loading, and potential toxicity of carriers themselves. To tackle the hindrance, carrier-free nanodrugs with biological activity have received increasing attention in cancer therapy. Extensive efforts have been made to exploit new self-assembly methods and mechanisms to expand the scope of carrier-free nanodrugs with enhanced therapeutic performance. In this review, we summarize the advanced progress and applications of carrier-free nanodrugs based on different types of assembly mechanisms and strategies, which involved noncovalent interactions, a combination of covalent bonds and noncovalent interactions, and metal ions-coordinated self-assembly. These carrier-free nanodrugs are introduced in detail according to their assembly and antitumor applications. Finally, the prospects and existing challenges of carrier-free nanodrugs in future development and clinical application are discussed. We hope that this comprehensive review will provide new insights into the rational design of more effective carrier-free nanodrug systems and advancing clinical cancer and other diseases (e.g., bacterial infections) infection treatment.

Assembly of graphene oxide-formate dehydrogenase composites by nickel-coordination with enhanced stability and reusability.

Featuring unique planar structure, large surface area and biocompatibility, graphene oxide (GO) has been widely taken as an ideal scaffold for the immobilization of various enzymes. In this regard, nickel-coordinated graphene oxide composites (GO-Ni) were prepared as novel supporters for the immobilization of formate dehydrogenase. The catalytic activity, stability and morphology were studied. Compared with GO, the enzyme loading capacity of GO-Ni was enhanced by 5.2-fold, besides the immobilized enzyme GO-Ni-FDH exhibited better thermostability, storage stability and reuse stability than GO-FDH. GO-Ni-FDH retained 40.9% of its initial activity after 3 h at 60°C, and retained 31.4% of its initial relative activity after 20 days' storage at 4°C. After eight times usages, GO-Ni-FDH maintained 63.8% of its initial activity. Mechanism insights of the multiple interactions of enzyme with the GO-Ni were studied, considering coordination bonds, hydrogen bonds, electrostatic forces, coordination bonds, and etc. A practical and simple immobilization strategy by metal ions coordination for multimeric dehydrogenase was developed.

Sustainable nitrogen-rich hierarchical porous carbon nest for supercapacitor application.

Chitosan has high synthetic flexibility, making it a promising nitrogenous bioresource for industrial applications. Nitrogen-rich hierarchically porous carbon (NHPC) was successfully synthesized by hydrothermal carbonization and self-activation of a chitosan-transition metal ion (Zn2+) complex. The N2 adsorption-desorption isotherm revealed that the as-made NHPC had large specific surface area (1067 m2 g-1) and a unique hierarchical pore structure (0.6-6.4 nm). Scanning electron microscopy (SEM) indicated a 3D finely interconnected nest architecture for NHPC. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the nitrogen atoms in the chitosan were protected by coordination with zinc ions, and most of them were still retained in the carbon matrix (6.36 at%) after high temperature activation. Electrochemical measurements exhibited that NHPC delivers a high specific capacitance (228.7 Fg-1 at 1 A g-1), impressive rate capability (the specific capacitance at 20 A g-1 was 174 Fg-1, maintaining 74.6% of the initial capacitance at 0.5 A g-1), and outstanding long-term cycling stability (98.3% retention after 5000 cycles), together with excellent energy density of 25.7 Wh kg-1 at the power density of 500 W kg-1. This study offers a novel strategy for synthesizing NHPC as one of the desirable electrode material candidates for energy storage.