Deregulation of New Cell Death Mechanisms in Leukemia.

Hematological malignancies are among the top five most frequent forms of cancer in developed countries worldwide. Although the new therapeutic approaches have improved the quality and the life expectancy of patients, the high rate of recurrence and drug resistance are the main issues for counteracting blood disorders. Chemotherapy-resistant leukemic clones activate molecular processes for biological survival, preventing the activation of regulated cell death pathways, leading to cancer progression. In the past decade, leukemia research has predominantly centered around modulating the well-established processes of apoptosis (type I cell death) and autophagy (type II cell death). However, the development of therapy resistance and the adaptive nature of leukemic clones have rendered targeting these cell death pathways ineffective. The identification of novel cell death mechanisms, as categorized by the Nomenclature Committee on Cell Death (NCCD), has provided researchers with new tools to overcome survival mechanisms and activate alternative molecular pathways. This review aims to synthesize information on these recently discovered RCD mechanisms in the major types of leukemia, providing researchers with a comprehensive overview of cell death and its modulation.

Preparation of blue- and green-emissive nitrogen-doped graphene quantum dots from graphite and their application in bioimaging.

Owing to the superior photoluminescence property, low toxicity and good biocompatibility, nitrogen-doped graphene quantum dots (NGQDs) have been regarded as promising nanomaterials for biological applications such as bioimaging. However, many of the preparation methods are complicated, high cost, eco-unfriendly, and with a low product yield. Here, we demonstrate a novel top-down approach for NGQDs preparation, in which the low cost graphite was used as a precursor, ammonium persulfate as an oxidative molecule and nitrogen source, and H2O2 as an oxidative agent, N-methyl-2-pyrrolidone as a solvent and potential functionalizer. Meanwhile, the solvent extraction was applied for the first time to purify NGQDs. The separated NGQDs display green and blue fluorescence, deriving from the difference sizes and nitrogen doped types. The total product yield of NGQDs is calculated to be about 52%, containing 88% of green-emissive NGQDs and 12% of blue-emissive NGQDs. Meanwhile, our NGQDs own low cytotoxicity, and display a good bioimaging performance in the in vitro and in vivo investigation. The synthesis idea in our work might be also applicable to obtain other kinds of quantum dots from the readily obtainable bulk materials.

Antibacterial Carbon-Based Nanomaterials.

The emergence and global spread of bacterial resistance to currently available antibiotics underscore the urgent need for new alternative antibacterial agents. Recent studies on the application of nanomaterials as antibacterial agents have demonstrated their great potential for management of infectious diseases. Among these antibacterial nanomaterials, carbon-based nanomaterials (CNMs) have attracted much attention due to their unique physicochemical properties and relatively higher biosafety. Here, a comprehensive review of the recent research progress on antibacterial CNMs is provided, starting with a brief description of the different kinds of CNMs with respect to their physicochemical characteristics. Then, a detailed introduction to the various mechanisms underlying antibacterial activity in these materials is given, including physical/mechanical damage, oxidative stress, photothermal/photocatalytic effect, lipid extraction, inhibition of bacterial metabolism, isolation by wrapping, and the synergistic effect when CNMs are used in combination with other antibacterial materials, followed by a summary of the influence of the physicochemical properties of CNMs on their antibacterial activity. Finally, the current challenges and an outlook for the development of more effective and safer antibacterial CNMs are discussed.