Antibacterial Quantum Dots

2021 ◽  
pp. 95-112
Keyword(s):  
Quantum Dots ◽  
Reaction Mechanisms ◽  
Graphene Quantum Dots ◽  
Physicochemical Characteristics ◽  
Antibacterial Activities ◽  
Research Progress ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Promising Area ◽  
Recent Research Progress

The emergence and global spread of multi antibiotic-resistant bacteria underscored the need to find new alternative antimicrobial candidates. Graphene quantum dots have received tremendous attention as promising new microbicidal agents owing to their ease of production, excellent physicochemical properties and high biosafety. In this chapter, the synthesis and physicochemical characteristics of graphene quantum dots are reviewed. A recent research progress on their antibacterial activities and the reaction mechanisms are also discussed. Lastly, an outlook on future development of effective graphene quantum dots was suggested with the goal of addressing current limitation and motivating further research on this promising area.

scholarly journals Hypochlorite-Activated Fluorescence Emission and Antibacterial Activities of Imidazole Derivatives for Biological Applications

2021 ◽  
Vol 9 ◽  
Author(s):  
Thanh Chung Pham ◽  
Van-Nghia Nguyen ◽  
Yeonghwan Choi ◽  
Dongwon Kim ◽  
Ok-Sang Jung ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Antibacterial Activities ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Fluorogenic Probe ◽  
High Fluorescence

The ability to detect hypochlorite (HOCl/ClO−) in vivo is of great importance to identify and visualize infection. Here, we report the use of imidazoline-2-thione (R1SR2) probes, which act to both sense ClO− and kill bacteria. The N2C=S moieties can recognize ClO− among various typical reactive oxygen species (ROS) and turn into imidazolium moieties (R1IR2) via desulfurization. This was observed through UV–vis absorption and fluorescence emission spectroscopy, with a high fluorescence emission quantum yield (ՓF = 43–99%) and large Stokes shift (∆v∼115 nm). Furthermore, the DIM probe, which was prepared by treating the DSM probe with ClO−, also displayed antibacterial efficacy toward not only Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) but also methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum ß-lactamase–producing Escherichia coli (ESBL-EC), that is, antibiotic-resistant bacteria. These results suggest that the DSM probe has great potential to carry out the dual roles of a fluorogenic probe and killer of bacteria.

scholarly journals Nitrogen Functionalities of Amino-Functionalized Nitrogen-Doped Graphene Quantum Dots for Highly Efficient Enhancement of Antimicrobial Therapy to Eliminate Methicillin-Resistant Staphylococcus aureus and Utilization as a Contrast Agent

2021 ◽  
Vol 22 (18) ◽  
pp. 9695
Author(s):  
Wen-Shuo Kuo ◽  
Ping-Ching Wu ◽  
Chi-Yao Hung ◽  
Chia-Yuan Chang ◽  
Jiu-Yao Wang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Quantum Dots ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Continuous Wave ◽  
Graphene Quantum Dots ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Methicillin Resistant ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

There is an urgent need for materials that can efficiently generate reactive oxygen species (ROS) and be used in photodynamic therapy (PDT) as two-photon imaging contrast probes. In this study, graphene quantum dots (GQDs) were subjected to amino group functionalization and nitrogen doping (amino-N-GQDs) via annealing and hydrothermal ammonia autoclave treatments. The synthesized dots could serve as a photosensitizer in PDT and generate more ROS than conventional GQDs under 60-s low-energy (fixed output power: 0.07 W·cm−2) excitation exerted by a 670-nm continuous-wave laser. The generated ROS were used to completely eliminate a multidrug-resistant strain of methicillin-resistant Staphylococcus aureus (MRSA), a Gram-positive bacterium. Compared with conventional GQDs, the amino-N-GQDs had superior optical properties, including stronger absorption, higher quantum yield (0.34), stronger luminescence, and high stability under exposure. The high photostability and intrinsic luminescence of amino-N-GQDs contribute to their suitability as contrast probes for use in biomedical imaging, in addition to their bacteria tracking and localization abilities. Herein, the dual-modality amino-N-GQDs in PDT easily eliminated multidrug-resistant bacteria, ultimately revealing their potential for use in future clinical applications.

scholarly journals Discovering Novel Antimicrobial Peptides in Generative Adversarial Network

2021 ◽  
Author(s):  
Tzu-Tang Lin ◽  
Li-Yen Yang ◽  
Ching-Tien Wang ◽  
Ga-Wen Lai ◽  
Chi-Fong Ko ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Antibacterial Activities ◽  
Resistant Bacteria ◽  
Antibacterial Effects ◽  
Generative Adversarial Network ◽  
Antibiotic Resistant ◽  
Adversarial Network ◽  
Carbapenem Resistant ◽  
Disk Diffusion Testing

Due to the growing number of clinical antibiotic resistance cases in recent years, novel antimicrobial peptides (AMPs) can become ideal for next-generation antibiotics. This study trained a deep convolutional generative adversarial network (GAN) with known AMPs to generate novel AMP candidates. The quality of the GAN-designed peptides was evaluated in silico, and eight of them named GAN-pep 1~8 were chosen to be synthesized for further experiments. Disk diffusion testing and minimum inhibitory concentration (MIC) determination were used to determine the antibacterial effects of the synthesized GAN-designed peptides. Seven out of the eight synthesized GAN-designed peptides showed antibacterial activities. Additionally, GAN-pep 3 and GAN-pep 8 had a broad spectrum of antibacterial effects. Both of them were also effective against antibiotic-resistant bacteria strains such as methicillin-resistant Staphylococcus aureus (S. aureus) and carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa). GAN-pep 3, the most promising GAN-designed peptide candidate, had low MICs against all the tested bacteria.

Graphene quantum dots/ZnO nanocomposite: Synthesis, characterization, mechanistic investigations of photocatalytic and antibacterial activities

2020 ◽  
Vol 761 ◽  
pp. 138009 ◽  
Author(s):  
S. Sheik Mydeen ◽  
R. Raj Kumar ◽  
R. Sivakumar ◽  
S. Sambathkumar ◽  
M. Kottaisamy ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Antibacterial Activities ◽  
Mechanistic Investigations

Silver nanoparticles coated by green graphene quantum dots for accelerating the healing of MRSA-infected wounds

2020 ◽  
Vol 8 (23) ◽  
pp. 6670-6682 ◽  
Author(s):  
Xianghua Zhong ◽  
Chunyi Tong ◽  
Tiansheng Liu ◽  
Li Li ◽  
Xu Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Silver Nanoparticles ◽  
Bacterial Infection ◽  
Human Health ◽  
Graphene Quantum Dots ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Clinical Therapy ◽  
Infected Wounds

Bacterial infection, especially multidrug-resistant bacteria-induced infection, threatens human health seriously, which has posed great challenges for clinical therapy.

scholarly journals Synthesis and Applications of Functional Nanomaterials

2021 ◽  
Vol 2133 (1) ◽  
pp. 012006
Author(s):  
Yujia Li ◽  
Hanzheng Xia ◽  
Jingyi Xu
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Chemical Properties ◽  
Research Progress ◽  
Synthesis Methods ◽  
Field Environment ◽  
Application Potential ◽  
Self Assembled ◽  
Reflective Coatings ◽  
Physical And Chemical

Abstract The unique physical and chemical properties and variable application potential of nanomaterials are continuously devoted to stimulating scientists’ studying enthusiasm. Extremely fine grains bring quantities excellent properties such as low density, low elastic modulus, high resistance and low thermal conductivity to nanomaterials, which has extensive use in the photoelectric field, environment, bioengineering and other fields. The research progress of graphene quantum dots, transparent reflective coatings and self-assembled nanotubes are mainly demonstrated. This paper shows the role of graphene quantum dots in solar cells, summarizes the synthesis methods of self-assembled nanotubes and their applications in bioengineering, and describes the development of transparent thermal reflective coatings for energy-saving glass attributed to providing relevant reference and basis for the development and research of nanomaterials.

scholarly journals Antioxidant and Antibacterial Properties of Extracts and Bioactive Compounds in Bryophytes

2021 ◽  
Vol 12 (1) ◽  
pp. 160
Author(s):  
Piergiorgio Cianciullo ◽  
Viviana Maresca ◽  
Sergio Sorbo ◽  
Adriana Basile
Keyword(s):  
Oxidative Stress ◽  
Antibacterial Properties ◽  
Natural Antioxidants ◽  
Antibacterial Activities ◽  
New Drugs ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Isolation And Characterization ◽  
State Of Research

Today global health problems such as increased risks of oxidative stress-related diseases and antibiotic resistance are issues of serious concern. Oxidative stress is considered to be the underlying cause of many contemporary pathological conditions such as neurological disorders, ischemia, cancer, etc. Antibiotic-resistant bacteria are a concerning issue in clinical practice, causing an increase in deadly infections. Bryophytes synthesize an outstanding number of secondary metabolites that have shown several potential therapeutic and nutraceutical applications. Research in the field has led to the isolation and characterization of several compounds (flavonoids, terpenoids, and bibenzyls). Some of these compounds have shown promising in vitro antibacterial activities and antioxidant potential comparable to known natural antioxidants such as ascorbic acid and α-tocopherol. However, the process of developing new drugs from naturally occurring molecules is often an impervious path. In this paper, the current state of research of bryophytic antioxidant and antibacterial applications is discussed.

scholarly journals Silver Nanoparticle-Based Nanocomposites for Combating Infectious Pathogens: Recent Advances and Future Prospects

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 581
Author(s):  
Md A. Wahab ◽  
Luming Li ◽  
Hongmei Li ◽  
Ahmed Abdala
Keyword(s):  
Biomedical Applications ◽  
Antibacterial Agents ◽  
Structural Parameters ◽  
Antibacterial Activities ◽  
Food Preservation ◽  
Resistant Bacteria ◽  
Ag Nps ◽  
Antibiotic Resistant ◽  
The Impact ◽  
Careful Investigation

Silver nanoparticles (Ag NPs) and their nanocomposites with polymers are potent agents for antibacterial and disinfectant applications. The structural parameters of Ag-NPs, such as size, shape, and surface area, are very critical for developing appropriate formulations for the targeted applications. The impact of these factors on the performance of Ag NPs is analyzed. Ag NPs with a broad spectrum of antibacterial activities have already found applications in wound and burn dressing, food preservation, agricultural ponds, treatment for infected areas, coatings, water treatment, and other biomedical applications. Ag NPs are quite useful against antibiotic-resistant bacteria, but their level of toxicity needs careful investigation as their toxicity could be very harmful to human health and the environment. This review discusses the challenges and prospects of various Ag NPs and their composites. The review will enrich the knowledge about the efficiency and mechanism of various Ag nanoparticle-based antibacterial agents.

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