scholarly journals Crosslinking, Mechanical Properties, and Antimicrobial Activity of Photocurable Diacrylate Urethane/ZnO-Ag Nanocomposite Coating

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Truc Vy Do ◽  
Minh Nguyet Ha ◽  
Tuan Anh Nguyen ◽  
Hoang Thu Ha ◽  
Thien Vuong Nguyen

In this article, ZnO-Ag nanohybrids were chemically synthesized in the aqueous medium by reducing silver nitrate with sodium borohydride NaBH4. These nanohybrids were then homogeneously dispersed into the diacrylate urethane/1,6-hexanediol diacrylate resin system at a content of 2 wt%. The structural morphology, mechanical resistances, and crosslinking of the as-prepared nanocomposite coating (nanocoating) were evaluated. The antimicrobial characteristic was tested by keeping track of the lag-log growth phase of E. coli bacteria in the coating existence among cell cultures. The obtained data indicated that the nanohybrids added into the UV curing diacrylate urethane matrices had significantly increased the abrasion resistance, relative hardness, and conversion of the acrylate groups of the nanocoating. In addition, the antibacterial test revealed that the nanocoating had good antibacterial property against E. coli, whereas for the pure coating (without ZnO-Ag nanoparticles), there was no antibacterial activity observed.

2020 ◽  
Vol 11 (2) ◽  
pp. 35-41
Author(s):  
Callixte Yadufashije ◽  
Adolyne Niyonkuru ◽  
Emanuel Munyeshyaka ◽  
Sibomana Madjidi ◽  
Joseph Mucumbitsi

Background: Ginger (Zingiber officinale) has been used for long time due to its potential antimicrobial activity against diversity of microbial pathogens. Aims and Objectives: The study was carried out to investigate the bacteria pathogens found in digestive tract infections and assess antimicrobial activities of ginger extract to identified bacteria. Materials and Methods: Bacteriological studies were carried out on stool samples from 30 patients attending Muhoza health center. Different types of bacteria were isolated from stool samples of digestive tract infection patients by using various methods such culture, biochemical test and antimicrobial activity of ginger extracts was analyzed at INES-Ruhengeri in clinical microbiology laboratory. Results: Study findings showed isolated bacteria and antibacterial activity of Ginger. Isolated bacteria and their percentages including Escherichia coli (46.6%) which is the predominant isolated bacteria, Salmonella species (33.33%), Enterobacter spp (10.0%), Shigella spp (6.6%) and Citrobacter (3.33%) which is the least isolated bacteria. Antibacterial activity of ginger was seen on isolated bacteria, as ethanol and methanol were used for ginger oil extraction, the antibacterial activity of ginger extracts using ethanol was seen on isolated bacteria such us Citrobacter spp with 14 mm of inhibition zone, Shigella spp with 12 mm, Salmonella with 11.1 mm, E. coli with 9.5 mm and Enterobacter spp which was seen to be resistant to ginger extract using ethanol with 0.66mm of inhibition zone. For methanol extracts antibacterial activity was seen as follows: Citrobacter spp at 12 mm, Shigella spp at 11 mm, E. coli at 8 mm, salmonella spp at 6.1 mm, and Enterobacter spp with 5 mm. Enterobacter spp was seen to be the most resistant bacteria in both extracts. Conclusion: Ginger has shown to have an antibacterial activity on bacteria isolated from digestive tract infected patients. It can be used as a medicine to treat these infections. Number of researches should be done to be sure on this reality of antibacterial activity of ginger.


2020 ◽  
Vol 13 (9) ◽  
pp. 229
Author(s):  
Volodymyr Horishny ◽  
Victor Kartsev ◽  
Vasyl Matiychuk ◽  
Athina Geronikaki ◽  
Petrou Anthi ◽  
...  

Herein we report the design, synthesis, computational, and experimental evaluation of the antimicrobial activity of fourteen new 3-amino-5-(indol-3-yl) methylene-4-oxo-2-thioxothiazolidine derivatives. The structures were designed, and their antimicrobial activity and toxicity were predicted in silico. All synthesized compounds exhibited antibacterial activity against eight Gram-positive and Gram-negative bacteria. Their activity exceeded those of ampicillin and (for the majority of compounds) streptomycin. The most sensitive bacterium was S. aureus (American Type Culture Collection ATCC 6538), while L. monocytogenes (NCTC 7973) was the most resistant. The best antibacterial activity was observed for compound 5d (Z)-N-(5-((1H-indol-3-yl)methylene)-4-oxo-2-thioxothiazolidin-3-yl)-4-hydroxybenzamide (Minimal inhibitory concentration, MIC at 37.9–113.8 μM, and Minimal bactericidal concentration MBC at 57.8–118.3 μM). Three most active compounds 5d, 5g, and 5k being evaluated against three resistant strains, Methicillin resistant Staphilococcus aureus (MRSA), P. aeruginosa, and E. coli, were more potent against MRSA than ampicillin (MIC at 248–372 μM, MBC at 372–1240 μM). At the same time, streptomycin (MIC at 43–172 μM, MBC at 86–344 μM) did not show bactericidal activity at all. The compound 5d was also more active than ampicillin towards resistant P. aeruginosa strain. Antifungal activity of all compounds exceeded those of the reference antifungal agents bifonazole (MIC at 480–640 μM, and MFC at 640–800 μM) and ketoconazole (MIC 285–475 μM and MFC 380–950 μM). The best activity was exhibited by compound 5g. The most sensitive fungal was T. viride (IAM 5061), while A. fumigatus (human isolate) was the most resistant. Low cytotoxicity against HEK-293 human embryonic kidney cell line and reasonable selectivity indices were shown for the most active compounds 5d, 5g, 5k, 7c using thiazolyl blue tetrazolium bromide MTT assay. The docking studies indicated a probable involvement of E. coli Mur B inhibition in the antibacterial action, while CYP51 inhibition is likely responsible for the antifungal activity of the tested compounds.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Iffat Naz

The present study is focused on the assessment of the antimicrobial activity of cerumen and antibiotics against bacteria isolated from ear pus samples. Thus, a total of 50 ear pus samples were collected from infected patients using sterile swabs and were screened using pure culture techniques. Total of 04 different bacterial isolates were identified while, the prevalence data revealed that Pseudomonas spp., were dominant (58%, n = 29) among isolated bacteria followed by Staphylococcus spp., (22%, n = 11), Escherichia coli (14%, n = 7) and Proteus spp., (6%, n = 3). Further, bioassay revealed that Pseudomonas spp., and Staphylococcus spp., were most sensitive to Clindamycin (94.73%) while displayed resistant to Ciprofloxacin and Ampicillin. Similarly, E. coli and Proteus spp., were most sensitive to Ciprofloxacin (92.8-95.21%) as compared to the other antibiotics. Moreover, antibacterial activity of cerumen was also assessed against test organisms and its maximum activity was observed against Pseudomonas spp., (90% equivalent to Clindamycin potency) and Staphylococcus spp., (60% equivalent to Amoxicillin potency) while least effective against E. coli (36%) and Proteus spp., (22%). Thus, it was concluded that the antibacterial activity of cerumen might be due to the presence of potential chemicals i.e. flavonoids and terpenoids.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Marta Bregón-Villahoz ◽  
Maria-Dolores Moragues ◽  
Inés Arrieta-Aguirre ◽  
Mikel Azkargorta ◽  
Lucía Lainz ◽  
...  

Purpose. Some microbiota patterns have been associated with favorable IVF prognosis and others with pathological conditions. The endometrial fluid aspirate (EFA) contains antibacterial proteins that are enriched in implantative IVF cycles, but the antimicrobial effect of EFA has not been addressed. We aimed to evaluate the antimicrobial activity of the human endometrial fluid during the natural cycle. Methods. EFA was obtained through an embryo transfer catheter in 38 women, aged 18-40 years, with regular cycles attending to a fertility clinic. The antimicrobial activity of EFAs was tested against two strains of Staphylococcus aureus; one strain each of Streptococcus agalactiae, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae; and three yeasts (Candida albicans, Candida glabrata, and Candida krusei). Results. All samples exhibited antibacterial activity against S. aureus. In addition, 32.4% of EFAs were active against one of the other microorganisms assayed, 16.2% against two, and 5.4% against four of them. In contrast, none exhibited antibacterial activity against E. coli or K. pneumoniae. The antimicrobial activity differs considerably between EFA samples, and we failed to observe a cycle-related pattern. Conclusions. EFA presented two antimicrobial activity patterns: (a) one common to all the samples, exhibiting activity against S. aureus and lack of activity against E. coli and K. pneumoniae, and (b) an individualized pattern, showing activity against some of the other microorganisms tested. The intensity of antibacterial activity differs between EFA samples. Our data suggest that the uterine microbiota is controlled by means of endometrial fluid components.


2021 ◽  
Vol 33 (10) ◽  
pp. 2393-2399
Author(s):  
BA. Anandh ◽  
R. Sakthivel ◽  
A. Shankar Ganesh ◽  
S. Subramani ◽  
A.T. Rajamanickam

Thin films of pure zinc oxide (ZnO) and aluminium (Al) doped ZnO were deposited by two step SILAR technique. Pure and Al (1%, 3%, 5%) doped ZnO thin film’s structural, morphology and optical properties were analyzed. Diffraction peaks of all the samples were indexed to hexagonal Wurtizite structure. The crystallite size, lattice parameters, dislocation density and microstrain were calculated for the prepared thin films. Morphology study using FESEM shows spherical shaped structure of pure ZnO and hexagonal faced rod like structure for Al doped ZnO thin films. The UV-vis absorption spectrum for the thin films was also studied. There is decrease in bandgap as the Al doping ratio increases from 1% to 5%. Photoluminescence studies confirmed that oxygen ion vacancy and interstitial Zn+ ion were present. The maximum zone of inhibition was studied against the Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria by agar diffusion method. Significant antimicrobial results were seen in pure and Al doped ZnO. Aluminium doped ZnO shows more antimicrobial activity over pure ZnO.


2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Jie Pei ◽  
Lin Xiong ◽  
Min Chu ◽  
Xian Guo ◽  
Ping Yan

Abstract Background Lactoferricin (Lfcin) is an antimicrobial activity center of lactoferrin, produced by hydrolysis from the N-terminal of lactoferrin. It was hypothesized that the intramolecular disulfide bond in Lfcin could affect its antibacterial function through influencing its molecular structure. To prove this hypothesis, bovine Lfcin (bLfcin) and its two derivatives, bLfcin with an intramolecular disulfate bond (bLfcin DB) and bLfcin with a mutation C36G (bLfcin C36G), were synthesized, purified, and identified. The circular dichroism spectra of the peptides were detected in solutions with different ionic and hydrophobic strength. The antibacterial activity of the peptides against Trueperella pyogenes, separated from cow milk with mastitis, were determined. Results The secondary structure of bLfcin DB showed more β-turn and less random coil than the other peptides in H2O, similar ratios of secondary structures with bLfcin and bLfcin C36G under ionic conditions, and close percentages of secondary structure with bLfcin under hydrophobic conditions. The synthetic peptides exhibited strong antimicrobial activity against T. pyogenes isolates, T. pyogenes ATCC 19,411, and E. coli ATCC 25,922. The antimicrobial activities of the three peptides were greater against T. pyogenes than against E. coli, and bLfcin DB exhibited higher antibacterial activity compared with its derivatives. Conclusions The intramolecular disulfide bond could change the molecular structure of bLfcin under alternative ionic strengths and hydrophobic effects, and the formation of the disulfide bond is beneficial to executing the antibacterial function of bLfcin.


2018 ◽  
Vol 16 (2) ◽  
pp. 104-113 ◽  
Author(s):  
Shyamal Baruah ◽  
Amrit Puzari ◽  
Farhana Sultana ◽  
Jayanta Barman

Introduction: A series of (R)-(-)-4-Phenyl-2 oxazolidinone based azetidinones (4a-i) were synthesized from the reaction of (2-Oxo-4-phenyl-oxazolidin-3-yl) acetic acid with aromatic imines (3a-i) in the presence of Thionyl chloride and Triethylamine as a base. Methods: The transformation proceeds through the formation of acid chloride to ketene which finally forms the azetidinones through [2+2] cycloaddition with aromatic imines. Products obtained were screened to evaluate their antibacterial activity with respect to known bacteria like Escherichia Coli (E. Coli) and Bacillus subtilis. Results and Conclusion: In most of the cases, azetidinones were found to exhibit superior antimicrobial properties than oxazolidinones. They were found to be a good inhibitor of gram-positive and gramnegative bacteria. Enhancement of antibacterial property can be attributed to the presence of azetidinone ring and hydrophobic alkyl side chain in the scaffolds.


2020 ◽  
Vol 11 (1) ◽  
pp. 61-65
Author(s):  
Farhana Momotaz ◽  
Ayesha Siddika ◽  
Md Tashrif Shaihan ◽  
Md Anisul Islam

In this study, the ZnO nanoparticles solution was directly applied on to the 100% cotton knit & woven fabric to impart antibacterial property using both spin coater & pad-dry-cure method. Then, the disc diffusion method was used to assess the antibacterial activity of the finished fabrics. The topographical analysis of untreated, treated, and washed fabrics of different structures (knit and woven) were studied and compared. The results showed that the finished fabric demonstrated significant antibacterial activity against S. aureus and E. coli. As per result, it was also found that double jersey (rib) fabric showed highest amount of bacterial protection & pad-dry-cure method showed better result against bacterial attack than spin coating method. Moreover, gram negative bacteria (E. coli) showed more strength against antibacterial treated unwashed and washed fabrics than gram positive bacteria (S. aureus). Journal of Engineering Science 11(1), 2020, 61-65


2013 ◽  
Vol 750-752 ◽  
pp. 1609-1612 ◽  
Author(s):  
Yang Ti ◽  
Jian Ru Wu ◽  
Da Jun Chen

In this paper, Fe-OCAP/PU blends were prepared. The mechanical properties and thermal stability of the samples were studied by tensile tests and thermogravimetric analysis, respectively. Results showed that the mechanical properties and thermal stability of the samples were improved with the increase of Fe-OCAP content. The antibacterial property of Fe-OCAP and Fe-OCAP/PU films was investigated by agar diifusion method and shake flask method, respectively. Fe-OCAP and Fe-OCAP/PU films showed efficient antibacterial activity againstS.aureus.


e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 262-271
Author(s):  
Chun Wu ◽  
Yongsi Yan ◽  
Yucheng Wang ◽  
Ping Sun ◽  
Rongrong Qi

AbstractAntibacterial epoxy resins (EP) have great potential in medical and electronic fields. During the process of extracting artemisinin from Artemisia annua, artemisia naphtha (AN) is generated as waste. The components of AN show antibacterial activity, and hence, it is introduced as a novel antibacterial agent in the epoxy matrix. In this study, the properties of epoxy resins with various AN loading were investigated. The results showed that AN/EP composites presented strong antibacterial activity against Escherichia coli and Staphylococcus aureus at the sterilization ratio of 100% against E. coli and 99.96% against S. aureus, respectively. Meanwhile, the thermal properties (curing temperature and glass transition temperature) of AN/EP composites remained well, and the mechanical property was even improved. Especially, the flexural strength of AN/EP composites could be reinforced by 62.9% when the content of AN was up to 5 wt%. For comparison, Artemisia annua powder (AAP), which was directly smashed from natural A. annua, was also mixed with epoxy resins as an antibacterial agent and showed excellent antibacterial property. Therefore, antibacterial epoxy composites containing A. annua waste as a natural resource with the enhanced mechanical property may have enormous potential in future biological and healthcare fields.


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