scholarly journals Broad-spectrum Antimicrobial ZnMintPc Encapsulated in Magnetic-nanocomposites with Graphene Oxide/MWCNTs Based on Bimodal Action of Photodynamic and Photothermal Effect

2022 ◽  
Author(s):  
Coralia Fabiola Cuadrado ◽  
Antonio Díaz-Barrios ◽  
Kleber Orlando Campana ◽  
Eric Cardona Romani ◽  
Francisco Javier Quiroz ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Broad Spectrum ◽  
Antimicrobial Agents ◽  
Zinc Phthalocyanine ◽  
Precipitation Method ◽  
Photothermal Effect ◽  
Magnetic Nanocomposites ◽  
Second Phase ◽  
Glycol Diacrylate

Microbial diseases have been declared one of the main threats to humanity, which is why, in recent years, great interest has been generated in the development of nanocomposites with antimicrobial capacity. In the present work, two magnetic nanocomposites, based on Graphene Oxide (GO) and Multiwall Carbon Nanotubes (MWCNTs) were studied. The synthesis of these magnetic nanocomposites consisted of three phases: first, the synthesis of Iron Magnetic Nanoparticles (MNPs) was carried out in the presence of MWCNTs and GO using the Co-precipitation method. The second phase consisted of the adsorption of photosensitizer menthol-Zinc phthalocyanine (ZnMintPc) into MWCNTs and GO, and the third phase was the encapsulation in poly (N-vinylcaprolactam-co-poly(ethylene glycol diacrylate)) poly (VCL-co-PEGDA) polymer VCL/PEGDA a biocompatible hydrogel, in order to obtain the magnetic nanocomposites: VCL/PEGDA-MNPs-MWCNTs-ZnMintPc and VCL/PEGDA-MNPs-GO-ZnMintPc. In vitro studies were carried out using Escherichia coli and Staphylococcus aureus bacteria and the Candida albicans yeast based on the PTT/PDT effect. This research describes the optical, morphological, magnetic and photophysical characterizations of nanocomposites and their application as antimicrobial agents. It was evaluated the antimicrobial effect of magnetics nanocomposites based on the Photodynamic/Photothermal (PDT/PTT) effect; for this purpose, doses of 65 mW cm-2 at 630 nm of light were used. The VCL/PEGDA-MNPs-GO-ZnMintPc nanocomposite was able to eliminate colonies of E. coli and S. aureus, while VCL/PEGDA-MNPs-MWCNTs-ZnMintPc nanocomposite was able to eliminate the three types of microorganisms; consequently, the latter is considered a broad-spectrum of antimicrobial agent in PDT and PTT.

Preliminary in Vitro Investigations on The Inhibitory Activity of The Original Dietary Supplement Oxidal® on Pathogenic Bacterial Strains

2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov
Keyword(s):  
Dietary Supplement ◽  
Broad Spectrum ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Clinical Effectiveness ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Microbial Strains

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.

scholarly journals Photothermal-assisted antibacterial application of GO-Ag against clinical isolated MDR E. coli

2019 ◽  
Author(s):  
Yuqing Chen ◽  
Wei Wu ◽  
Zeqiao Xu ◽  
Cheng Jiang ◽  
Shuang Han ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Near Infrared ◽  
Antibacterial Effect ◽  
Luria Bertani ◽  
Fluorescent Imaging ◽  
Photothermal Effect ◽  
Antibacterial Efficiency ◽  
E Coli ◽  
Morphology Characterization

Abstract Background: Treatment of multidrug-resistant (MDR) bacterial infection is a great challenge in public health. Herein, we provide a solution to this problem with the use of graphene oxide-silver (GO-Ag) nanocomposites as anti-bacterial agent. Methods: Following established protocols, silver nanoparticles were grown on graphene oxide sheets. Then, a series of in-vitro studies were conducted to validate the antibacterial efficiency of the GO-Ag nanocomposites against clinical MDR Escherichia coli (E. coli) strains. Firstly, minimum inhibitory concentrations (MICs) of different antimicrobials were tested against MDR E. Coli strains. Then, bacteria viability assessments were conducted with different nanomaterials in Luria-Bertani (LB) broth. Afterwards, photothermal irradiation was conducted on MDR E. coli with lower GO-Ag concentration. At last, fluorescent imaging and morphology characterization using scanning electron microscope (SEM) were done to find the possible cause of antibacterial effect. Results: GO-Ag nanocomposites showed the highest antibacterial efficiency among tested antimicrobials. Synergetic antibacterial effect was observed in GO-Ag nanocomposites treated group. The remained bacteria viabilities were 4.4% and 4.1% respectively for different bacteria strains with GO-Ag concentration at 14.0 µg mL-1. In addition, GO-Ag nanocomposites have strong absorption in the near-infrared field and can convert the electromagnetic energy to heat. With the use of this photothermal effect, effective sterilization could be achieved using GO-Ag nanocomposites concentration as low as 7.0 µg mL-1. Fluorescent imaging and morphology characterization were used to analyze bacteria living status, which uncovered that bacteria integrity was disrupted after GO-Ag nanocomposites treatment. Conclusions: GO-Ag nanocomposites are proved to be efficient antibacterial agent against multi-drug resistant E. coli. Their strong antibacterial effect arises from inherent antibacterial property and photothermal effect that provides aid for bacteria killing.

scholarly journals Synergistic Antifungal Activity of Graphene Oxide and Fungicides against Fusarium Head Blight In Vitro and In Vivo

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2393
Author(s):  
Xiuping Wang ◽  
Fei Peng ◽  
Caihong Cheng ◽  
Lina Chen ◽  
Xuejuan Shi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Plant Pathogens ◽  
Antimicrobial Agents ◽  
Plant Protection ◽  
Disease Incidence ◽  
Agricultural Science ◽  
Plant Diseases ◽  
Synergistic Activity

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest management.

scholarly journals Cranberry-Derived Proanthocyanidins Potentiate β-Lactam Antibiotics Against Resistant Bacteria

2021 ◽  
Author(s):  
Mathias Gallique ◽  
Kuan Wei ◽  
Vimal B. Maisuria ◽  
Mira Okshevsky ◽  
Geoffrey McKay ◽  
...  
Keyword(s):  
Broad Spectrum ◽  
Antimicrobial Agents ◽  
Resistance Mechanisms ◽  
Resistant Bacteria ◽  
E Coli ◽  
New Generation ◽  
Future Work ◽  
Emergence Of Resistance

The emergence and spread of extended-spectrum β-lactamases (ESBLs), metallo-β-lactamases (MBLs) or variant low affinity penicillin-binding proteins (PBPs) pose a major threat to our ability to treat bacterial infection using β-lactam antibiotics. Although combinations of β-lactamase inhibitors with β-lactam agents have been clinically successful, there are no MBL inhibitors in current therapeutic use. Furthermore, recent clinical use of new generation cephalosporins targeting PBP2a, an altered PBP, has led to the emergence of resistance to these antimicrobial agents. Previous work shows that natural polyphenols such as cranberry-extracted proanthocyanidins (cPAC) can potentiate non-β-lactam antibiotics against Gram-negative bacteria. This study extends beyond previous work by investigating the in vitro effect of cPAC in overcoming ESBL-, MBL- and PBP2a-mediated β-lactam resistance. The results show that cPAC exhibit variable potentiation of different β-lactams against β-lactam resistant Enterobacteriaceae clinical isolates as well as ESBL- and MBL-producing E. coli. We also discovered that cPAC have broad-spectrum inhibitory properties in vitro on the activity of different classes of β-lactamases, including CTX-M3 ESBL and IMP-1 MBL. Furthermore, we observe that cPAC selectively potentiate oxacillin and carbenicillin against methicillin-resistant but not methicillin-sensitive Staphylococci, suggesting that cPAC also interfere with PBP2a-mediated resistance. This study motivates the need for future work to identify the most bioactive compounds in cPAC and to evaluate their antibiotic potentiating efficacy in vivo. IMPORTANCE Emergence of β-lactam resistant Enterobacteriaceae and Staphylococci compromised the efficiency of β-lactams-based therapy. By acquisition of ESBLs, MBLs or PBPs, it is highly likely that bacteria become completely resistant to the most efficient β-lactam agents in the near future. In this study, we described a natural extract rich in proanthocyanidins which exerts adjuvant properties by interfering with two different resistance mechanisms. By their broad-spectrum inhibitory ability, cranberry-extracted proanthocyanidins could have the potential to enhance effectiveness of existing β-lactam agents.

Graphene oxide and carbon dots as broad-spectrum antimicrobial agents – a minireview

2019 ◽  
Vol 4 (1) ◽  
pp. 117-137 ◽  
Author(s):  
Anisha Anand ◽  
Binesh Unnikrishnan ◽  
Shih-Chun Wei ◽  
C. Perry Chou ◽  
Li-Zhi Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Broad Spectrum ◽  
Carbon Dots ◽  
Antimicrobial Agents

Complex antibacterial mechanisms of graphene oxide and carbon dots.

Near-Infrared Light Enhanced Peroxidase-Like Activity of PEGylated Palladium Nanozyme for Highly Efficient Biofilm Eradication

2021 ◽  
Vol 17 (6) ◽  
pp. 1131-1147
Author(s):  
Sijin Xiang ◽  
Zhongxiong Fan ◽  
Duo Sun ◽  
Tianbao Zhu ◽  
Jiang Ming ◽  
...  
Keyword(s):  
Infection Control ◽  
Near Infrared ◽  
Antimicrobial Agents ◽  
Infrared Light ◽  
Photothermal Effect ◽  
Highly Efficient ◽  
Nir Light ◽  
Biofilm Infection

The overall eradication of biofilm-mode growing bacteria holds significant key to the answer of a series of infection-related health problems. However, the extracellular matrix of bacteria biofilms disables the traditional antimicrobials and, more unfortunately, hampers the development of the anti-infectious alternatives. Therefore, highly effective antimicrobial agents are an urgent need for biofilm-infection control. Herein, a PEGylated palladium nanozyme (Pd-PEG) with peroxidase (POD)-like activity for highly efficient biofilm infection control is reported. Pd-PEG also shows the intrinsic photothermal effect as well as near-infrared (NIR) light-enhanced POD-like activity in the acidic environment, thereby massively destroying the biofilm matrix and killing the adhering bacteria. Importantly, the antimicrobial mechanism of the synergistic treatment based on Pd-PEG+H2O2+NIR combination was disclosed. In vitro and in vivo results illustrated the designed Pd-PEG+H2O2 +NIR treatment reagent possessed outstanding antibacterial and biofilms elimination effects with negligible biotoxicity. This work hopefully facilitates the development of metal-based nanozymes in biofilm related infectious diseases.

Multicenter Evaluation of the In Vitro Activity of Six Broad-Spectrum β-Lactam Antimicrobial Agents in Puerto Rico

1998 ◽  
Vol 30 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Group ◽  
Gary V Doern ◽  
Ronald N Jones ◽  
Michael A Pfaller ◽  
Meridith Erwin ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Broad Spectrum ◽  
Antimicrobial Agents ◽  
Vitro Activity ◽  
In Vitro Activity
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