scholarly journals Metal nanoparticle antibacterial effect оn antibiotic-resistant strains of bacteria

2021 ◽  
Vol 11 (4) ◽  
pp. 771-776
Author(s):  
E. S. Udegova ◽  
K. A. Gildeeva ◽  
T. V. Rukosueva ◽  
S. Baker

The rapid formation of microbial resistance to modern antibacterial drugs requires to search for new, alternative therapies. It is known that some organisms, such as plants, algae, fungi, are able to convert inorganic metal ions into metal nanoparticles due to the recovery process carried out by proteins, sugars and metabolites contained in the tissues and cells of these organisms. At the same time, many plants (e.g., plantain, yarrow, wormwood, turmeric long, calendula, marsh bagulnik, etc.) and metals (copper, silver, gold, zinc, etc.) themselves have antibacterial properties, so that metal nanoparticles obtained by biological method, or via “Green” synthesis method, from extracts of such plants can become a current alternative to many modern antibacterial drugs. The antibacterial mechanism of action of nanoparticles depends on the type of microorganisms affected, as well as on the type of nanoparticles, their concentration, size, and how they are obtained. Based on this, the study of the antibacterial effect of nanoparticles is one of the promising directions of solving the problem of microbial antibiotic resistance. There was examined antibacterial effect of metal nanoparticles containing silver, copper and gold obtained by biological method from the salts of AgNO3, CuSO4, H[AuCl4] metals, respectively, and the extract of the plant — turmeric long (lat. Curcuma longa) — related to the following bacteria strain collection: E. coli (ATCC 25922), S. aureus (ATCC 25923), MRSA (ATCC 38591) and polyresistant clinical strains isolated from patients of the Regional clinical hospital (Krasnoyarsk) — К. рneumoniae, strain 104, P. аeruginosa, strain 40, P. аeruginosa, strain 215, А. baumannii, strain 210, А. baumannii, strain 211. Study allowed to identify the minimum suppressive concentration of nanoparticles by the method of serial dilutions (MUK 4.2.1890-04) with azurin dye. It was proved that metal nanoparticles exhibit different antibacterial efficacy depending on the type of nanometals used and bacterial cultures. Copper nanoparticles have the highest antibacterial activity, and gold nanoparticles have the lowest. The most marked antibacterial effect was observed against clinical polyresistant strains. Metal nanoparticles can become an alternative to the currently known antibacterial drugs, but despite the high efficiency of nanoparticles against polyresistant to antibacterial drugs microorganisms in vitro, it is necessary to take into account their possible toxic effect on live tissues, which requires further study in experiments in vivo.

2021 ◽  
Vol 1021 ◽  
pp. 270-279
Author(s):  
Abdulkader M. Alakrach ◽  
Awad A. Al-Rashdi ◽  
Taha Alqadi ◽  
Mohammed Abdulhakim Al Saadi ◽  
Sam Sung Ting ◽  
...  

Polylactic acid (PLA) nanocomposite samples with different properties like mechanical, thermal, barrier and antibacterial properties are good candidates as packaging biomaterials. Unique PLA/TiO2 and PLA/HNTs-TiO2 nanocomposite samples were fabricated by solution casting method. The mechanical and antibacterial properties of PLA/TiO2 and PLA/HNTs-TiO2 samples were investigated with comparing to the pristine PLA film as a control sample. PLA nanocomposite samples with TiO2 nanofillers showed poorer mechanical properties while PLA films with PLA/HNTs-TiO2 showed unique developments, which tensile strength improved by 46% with the incorporation of 5 wt%. The PLA nanocomposites showed a high efficiency to both Gram positive and Gram negative bacteria, significant antibacterial effect being proved after first week elapsed time by comparing to the control sample (presenting no antibacterial effect). By considering the multifunctional characteristics of PLA/TiO2 and PLA/HNTs-TiO2 nanocomposites, the samples produced by solution casting can be considered a favourable alternative as environmental-friendly packaging materials.


Author(s):  
R. I. Dovnar ◽  
A. Yu. Vasil’kov ◽  
T. M. Sakalova ◽  
A. V. Naumkin ◽  
A. V. Budnikov ◽  
...  

A quantitative assessment of the antibacterial effect of silver nanoparticles on polyantibiotic-resistant grampositive and gram-negative microorganisms was carried out. Silver nanoparticles were synthesized by the environmentally friendly metal-steam synthesis method. The size and electronic state of nanoparticles were investigated by transmission electron and X-ray photoelectron spectroscopy. The antibacterial properties of nanomaterials were assessed on two clinical pathogenic strains of gram-positive and four strains of gram-negative microorganisms. The typing and assessment of bacterial resistance to antibiotics were carried out on a microbiological analyzer. The antibacterial effect of nanoparticles was quantitatively assessed using the dilution method and the determination of the minimum inhibitory and minimum bactericidal concentrations.It was found that the studied silver nanoparticles have sizes in the range from 5 to 24 nm with an average diameter of 10.8 nm. It was shown that all clinical strains of microorganisms used in the study are characterized by multiple antibacterial resistance; the percentage of their antibiotic resistance ranges from 12.5 to 93.3 %. It was found that for the studied microorganism, the values of the minimum inhibitory concentration (MIC) are in the range from 7.81 to 31.25 μg/ml, and the minimum bactericidal concentration (MBC) is in the range from 31.25 to 62.50 μg/ml. The obtained MIC and MBC data can be used to create promising antimicrobial drugs and medical next generation devices.


2021 ◽  
Author(s):  
Jingze Li ◽  
Jiaxin Ma ◽  
Liu Hong ◽  
Cheng Yang

Abstract Achieving an efficient and inexpensive bactericidal effect is a key point for the design of antibacterial agent. Recent advances have proved molybdenum disulfide (MoS2) as a promising platform for antimicrobial applications, while the combination of metal nanoparticle would promote the antibacterial efficiency. Nevertheless, the dispersivity, cheapness and safety of metal nanoparticle loaded on MoS2 raised some concerns. In this paper, we successfully realized a uniform decoration of copper nanoparticles (CuNPs) on surface of MoS2 nanosheets, and the size of CuNPs could be controlled below 5 nm. Under 5 min irradiation of 660 nm visible light, the synthesized CuNPs/MoS2 composite demonstrated superior antibacterial performances (almost 100% bacterial killed) towards both Gram-negative E. coli and Gram-positive S. aureus over the single component (Cu or MoS2), while the bactericidal effect could last for at least 6 h. The synergism of photodynamic generated hydroxyl radical (∙OH), oxidative stress without reactive oxygen species (ROS) production and the release of Cu ions was considered as the mechanism for the antibacterial properties of CuNPs/MoS2. Our findings provided new insights into the development of two-dimensional antibacterial nanomaterials of high cost performance.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 369 ◽  
Author(s):  
Arumugam Saravanan ◽  
Moorthy Maruthapandi ◽  
Poushali Das ◽  
John H. T. Luong ◽  
Aharon Gedanken

Carbon dots (CDs) were obtained from medicinal turmeric leaves (Curcuma longa) by a facile one-step hydrothermal method and evaluated for their bactericidal activities against two gram-negative; Escherichia coli, Klebsiella pneumoniae, and two gram-positive counterparts; Staphylococcus aureus, S. epidermidis. The CDs exhibited spherical shapes with a mean size of 2.6 nm. The fluorescence spectra of CDs revealed intense fluorescence at λex/em = 362/429 nm with a bright blue color in an aqueous solution. The CDs showed strong photostability under various environmental conditions (pH, salt, and UV-radiation). The complete bactericidal potency of CDs was 0.25 mg/mL for E.coli and S. aureus after 8 h of exposure, while for K. pneumoniae, and S. epidermidis, the CDs at 0.5 mg/mL good antibacterial effect within 8 h and complete eradication after 24 h of exposure is observed. The release of reactive oxygen species played a crucial role in the death of the bacterial cell. The present study provides a strategy for the preparation of CDs from a medicinal plant and their potential antibacterial activities against four common contagious pathogens.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Atanu Naskar ◽  
Sohee Lee ◽  
Kwang-sun Kim

Antibiotic therapy is the gold standard for bacterial infections treatment. However, the rapid increase in multidrug-resistant (MDR) bacterial infections and its recent use for secondary bacterial infections in many COVID-19 patients has considerably weakened its treatment efficacy. These shortcomings motivated researchers to develop new antibacterial materials, such as nanoparticle-based antibacterial platform with the ability to increase the chances of killing MDR strains and prevent their drug resistance. Herein, we report a new black phosphorus (BP)-based non-damaging near-infrared light-responsive platform conjugated with ZnO and Au nanoparticles as a synergistic antibacterial agent against Staphylococcus aureus species. First, BP nanosheets containing Au nanoparticles were assembled in situ with the ZnO nanoparticles prepared by a low-temperature solution synthesis method. Subsequently, the antibacterial activities of the resulting Au–ZnO–BP nanocomposite against the non-resistant, methicillin-resistant, and erythromycin-resistant S. aureus species were determined, after its photothermal efficacy was assessed. The synthesized nanocomposite exhibited excellent anti-S. aureus activity and good photothermal characteristics. The non-resistant S. aureus species did not produce drug-resistant bacteria after the treatment of multiple consecutive passages under the pressure of the proposed nanoantibiotic, but rapidly developed resistance to erythromycin. This work clearly demonstrates the excellent photothermal antibacterial properties of Au–ZnO–BP nanocomposite against the MDR S. aureus species.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 519
Author(s):  
Florentina Monica Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Violeta Purcar

The recent development of several methods for extracting curcumin from the root of the plant Curcuma longa has led to intensified research on the properties of curcumin and its fields of application. Following the studies and the accreditation of curcumin as a natural compound with antifungal, antiviral, and antibacterial properties, new fields of application have been developed in two main directions—food and medical, respectively. This review paper aims to synthesize the fields of application of curcumin as an additive for the prevention of spoilage, safety, and quality of food. Simultaneously, it aims to present curcumin as an additive in products for the prevention of bacterial infections and health care. In both cases, the types of curcumin formulations in the form of (nano)emulsions, (nano)particles, or (nano)composites are presented, depending on the field and conditions of exploitation or their properties to be used. The diversity of composite materials that can be designed, depending on the purpose of use, leaves open the field of research on the conditioning of curcumin. Various biomaterials active from the antibacterial and antibiofilm point of view can be intuited in which curcumin acts as an additive that potentiates the activities of other compounds or has a synergistic activity with them.


2012 ◽  
Vol 239-240 ◽  
pp. 1522-1527
Author(s):  
Wen Bo Wu ◽  
Yu Fu Jia ◽  
Hong Xing Sun

The bottleneck assignment (BA) and the generalized assignment (GA) problems and their exact solutions are explored in this paper. Firstly, a determinant elimination (DE) method is proposed based on the discussion of the time and space complexity of the enumeration method for both BA and GA problems. The optimization algorithm to the pre-assignment problem is then discussed and the adjusting and transformation to the cost matrix is adopted to reduce the computational complexity of the DE method. Finally, a synthesis method for both BA and GA problems is presented. The numerical experiments are carried out and the results indicate that the proposed method is feasible and of high efficiency.


CrystEngComm ◽  
2015 ◽  
Vol 17 (2) ◽  
pp. 456-462 ◽  
Author(s):  
C. Tamames-Tabar ◽  
E. Imbuluzqueta ◽  
N. Guillou ◽  
C. Serre ◽  
S. R. Miller ◽  
...  

A novel biocompatible and bioactive zinc azelate metal–organic framework (BioMIL-5) was hydrothermally synthesized with interesting long-term antibacterial properties.


2021 ◽  
pp. 1-6
Author(s):  
Serap Yiğit Gezgin ◽  
Abdullah Kepceoğlu ◽  
Hamdi Şükür Kiliç

In this study, silver (Ag) nanoparticle thin films were deposited on microscope slide glass and Si wafer substrates using the pulsed-laser deposition (PLD) technique in Ar ambient gas pressures of 1 × 10−3 and 7.5 × 10−1 mbar. AFM analysis has shown that the number of Ag nanoparticles reaching the substrate decreased with increasing Ar gas pressure. As a result of Ar ambient gas being allowed into the vacuum chamber, it was observed that the size and height of Ag nanoparticles decreased and the interparticle distances decreased. According to the absorption spectra taken by a UV–vis spectrometer, the wavelength where the localised surface plasmon resonance (LSPR) peak appeared was shifted towards the longer wavelength region in the solar spectrum as Ar background gas pressure was decreased. This experiment shows that LSPR wavelength can be tuned by adjusting the size of metal nanoparticles, which can be controlled by changing Ar gas pressure. The obtained extinction cross section spectra for Ag nanoparticle thin film was theoretically analysed and determined by using the metal nanoparticle–boundary element method (MNPBEM) toolbox simulation program. In this study, experimental spectrum and simulation data for metal nanoparticles were acquired, compared, and determined to be in agreement.


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