Carbonized zein nanosheets with intrinsic enzyme-mimicking activities and high photothermal conversion efficiency for synergistic cancer therapy

A biodegradable and near-infrared light-activatable photothermal nanoconvertor for bacterial inactivation

The development of biodegradable nanomaterials for near-infrared photothermal antibacterial is of great significance to improve the biosafety of nano-antibacterial strategies in clinical application. In this study, a new nano-antibacterial strategy was developed, in which a biodegradable charge-transfer nanocomplex acted as a high-efficiency near-infrared light-activatable photothermal nanoconvertor. The charge-transfer nanocomplex was synthesized through oxidation-induced self-assembly of 3,3',5,5'-tetramethylbenzidine molecules. This nanocomplex can efficiently convert light energy around 900 nm into heat energy, with a photothermal conversion efficiency of up to 30%. More importantly, the nanocomplex can spontaneously degrade under physiological conditions within 12 hours. Utilizing the photothermal effect of this nanocomplex, both Gram-positive bacteria and Gram-negative bacteria can be inactivated within 2 minutes. In addition, the inactivation mechanism was systematically discussed and the results indicated that the photothermal effect induced bacterial cell membrane damage was probably responsible for the antibacterial effect.

Engineering the Stability of Nanozyme-Catalyzed Product for Colorimetric Logic Gate Operations

Recently, the design and development of nanozyme-based logic gates have received much attention. In this work, by engineering the stability of the nanozyme-catalyzed product, we demonstrated that the chromogenic system of 3, 3′, 5, 5′-tetramethylbenzidine (TMB) can act as a visual output signal for constructing various Boolean logic operations. Specifically, cerium oxide or ferroferric oxide-based nanozymes can catalyze the oxidation of colorless TMB to a blue color product (oxTMB). The blue-colored solution of oxTMB could become colorless by some reductants, including the reduced transition state of glucose oxidase and xanthine oxidase. As a result, by combining biocatalytic reactions, the color change of oxTMB could be controlled logically. In our logic systems, glucose oxidase, β-galactosidase, and xanthine oxidase acted as inputs, and the state of oxTMB solution was used as an output. The logic operation produced a colored solution as the readout signal, which was easily distinguished with the naked eye. More importantly, the study of such a decolorization process allows the transformation of previously designed AND and OR logic gates into NAND and NOR gates. We propose that this work may push forward the design of novel nanozyme-based biological gates and help us further understand complex physiological pathways in living systems.

Graphene and its Derivatives for Bone Tissue Engineering: In Vitro and In Vivo Evaluation of Graphene-Based Scaffolds, Membranes and Coatings

Bone regeneration or replacement has been proved to be one of the most effective methods available for the treatment of bone defects caused by different musculoskeletal disorders. However, the great contradiction between the large demand for clinical therapies and the insufficiency and deficiency of natural bone grafts has led to an urgent need for the development of synthetic bone graft substitutes. Bone tissue engineering has shown great potential in the construction of desired bone grafts, despite the many challenges that remain to be faced before safe and reliable clinical applications can be achieved. Graphene, with outstanding physical, chemical and biological properties, is considered a highly promising material for ideal bone regeneration and has attracted broad attention. In this review, we provide an introduction to the properties of graphene and its derivatives. In addition, based on the analysis of bone regeneration processes, interesting findings of graphene-based materials in bone regenerative medicine are analyzed, with special emphasis on their applications as scaffolds, membranes, and coatings in bone tissue engineering. Finally, the advantages, challenges, and future prospects of their application in bone regenerative medicine are discussed.