Carbon dots have drawn extensive attention in the detection of metal ions with good stability, excellent biocompatibility and low toxicity. Meanwhile, the quantum yield, response rate and the detection mechanism for Cu2+ ions are vital to their development and application. To obtain more selective and sensitive materials to detect Cu2+ ions, N-doped carbon dots (DN-CDs) were synthesized by a one-step hydrothermal method using citric acid as the carbon source and diethylenetriamine (DETA) as the nitrogen source. The obtained DN-CDs exhibited stable and intense blue light emission and special near-infrared up-conversion fluorescence at 820 nm, attributed to the effect of introducing N atoms into the structure of carbon dots. Due to the dynamic quenching of the DN-CDs by Cu2+ ions, the fluorescence intensity (λex = 820 nm) of DN-CDs was quantitatively decreased in the presence of Cu2+ ions. The DN-CDs had a rapid response within 3 min. The DN-CD system exhibited a linear relationship with a concentration range from 2.5 to 50 µM and low detection limit (LOD) of 42 nM. After careful investigation, an interesting conclusion was proposed: N-doped CDs with N/O = 1:1 or higher with relatively abundant N atoms prefer to detect Cu2+ ions while those with N/O = 1:2 or lower prefer to detect Fe3+ ions.
To overcome the problems of excessive ion release of inorganic antimicrobial agents and the biological toxicity of organic antimicrobial agents, metal organic framework (MOF) materials are attracting attention in the antimicrobial field due to their tunable structural properties and multifunctional applications. Most current studies are limited to zeolitic imidazolate framework-8 (ZIF-8), which has low antimicrobial efficiency by component release. Two-dimensional (2D) zeolitic imidazolate framework nanoleaf (ZIF-L) possesses better antimicrobial effect than ZIF-8 because of the physical destructionto bacteria by its blade tip. However, the in-situ synthesis method of two-dimensional ZIF-L, and the problem of leaf accumulation, limit the wider application of ZIF-L. In this paper, three-dimensional(3D) flower cluster-like ZIF-L (2–3 μm, +31.23 mv), with better antibacterial effects and a wider application range, was prepared by stirring without adding other reagents. To further improve the antibacterial performance of ZIF-L, nitrogen-doped carbon dots (NCDs) were electrostatically absorbed by ZIF-L to obtain NCDs@ZIF-L composites. The NCDs@ZIF-L composites showed over 95% and 85% antibacterial efficiency against E. coli and S. aureus, respectively, at a concentration of 0.25 mg/mL. In addition, polylactic acid (PLA) films mixed with ZIF-L and NCDs@ZIF-L composites with PLA showed good antimicrobial properties, indicating the applicability of ZIF-L and NCDs@ZIF-L composites for antibacterial materials. With a unique three-dimensional crystal shape and positive surface charge, ZIF-L and NCDs@ZIF-L composites exhibited excellent antibacterial properties, which provided a new perspective for the study of antimicrobial materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.