Multifunctional Carbon Nanodots for Antibacterial Enhancement, pH Change, and Poisonous Tin(IV) Specifical Detection

Carbon Nanodot-Microbe-Plant Nexus in Agroecosystem and Antimicrobial Applications

The intensive applications of nanomaterials in the agroecosystem led to the creation of several environmental problems. More efforts are needed to discover new insights in the nanomaterial-microbe-plant nexus. This relationship has several dimensions, which may include the transport of nanomaterials to different plant organs, the nanotoxicity to soil microbes and plants, and different possible regulations. This review focuses on the challenges and prospects of the nanomaterial-microbe-plant nexus under agroecosystem conditions. The previous nano-forms were selected in this study because of the rare, published articles on such nanomaterials. Under the study's nexus, more insights on the carbon nanodot-microbe-plant nexus were discussed along with the role of the new frontier in nano-tellurium-microbe nexus. Transport of nanomaterials to different plant organs under possible applications, and translocation of these nanoparticles besides their expected nanotoxicity to soil microbes will be also reported in the current study. Nanotoxicity to soil microbes and plants was investigated by taking account of morpho-physiological, molecular, and biochemical concerns. This study highlights the regulations of nanotoxicity with a focus on risk and challenges at the ecological level and their risks to human health, along with the scientific and organizational levels. This study opens many windows in such studies nexus which are needed in the near future.

Enhanced Antibacterial Activity against Escherichia coli Based on Cationic Carbon Dots Assembling with 5-Aminolevulinic Acid

Carbon dots (CDs) with positive surface charges are considered one of the encouraging nanomedications for antibacterial applications. However, due to the distinctive membrane structure of Gram-negative bacteria, cationic CDs with relatively high concentrations are usually required for effective treatment, which might bring out serious safety issues at high doses. Therefore, it is of substantial significance to improve the killing efficiency of cationic CDs on Gram-negative bacteria at appropriately low concentrations. In this work, optimized cationic CDs (bPEI25 000-CDs) were prepared via a hydrothermal method with citric acid and branched PEI25000, which offered a positive surface potential, elimination abilities against Escherichia coli, and relatively high biosafety. The optimized bPEI25 000-CDs can further assemble with the clinical photodynamic therapy (PDT) drug 5-aminolevulinic acid (5-ALA) through electrostatic interaction. Moreover, compared with bPEI25 000-CDs and 5-ALA, the bacterial survival rate was significantly reduced by the ALA-bPEI25 000-CD-induced PDT effect. Even when the dose of bPEI25 000-CD carrier was halved, the bacterial survival could be reduced by 44.4% after light exposure compared to those incubated in the dark. The investigation of the bacterial morphology, membrane potential, and intracellular ROS production suggested that the enhanced antibacterial activity may be due to the membrane dysfunction and cell damage resulting from the high interaction between positively charged ALA-bPEI25 000-CDs and the bacterial cell membrane. Meanwhile, the cationic ALA-bPEI25 000-CDs may facilitate the cellular uptake of 5-ALA, resulting in a more efficient PDT effect. In summary, the antibacterial strategy proposed in this study will provide a novel approach for expanding the application of CD-based nanomedications.