PDF Publication Title:
Text from PDF Page: 005
Nanomaterials 2021, 11, 96 5 of 19 heat cured at 140 ◦C for 90 min. The weight of each film sample was 28–30 mg and eight replicates were prepared for each film type. Controls, also prepared as eight replicates, consisted of PVA powder (27 mg) or 10% w/w PVA gel (270 mg), each of which was added to 2.5 mL of water. Prior to the experiments, each bacterial species was cultured overnight from freezer stocks (10 μL bacterial sample into 10 mL Luria Bertani (LB) broth) followed by a second sub-culture (100 μL in 10 mL LB broth) until an optical density of ~0.3–0.5 at λ = 600 nm was reached, as measured using an Eppendorf BioPhotometer (Eppendorf Canada, Mississauga, ON, Canada), at which point bacteria were used as outlined below. The antibacterial activity of PVA-silver films was assessed by placing pre-weighed film samples in nutrient media containing uropathogenic E. coli, S. aureus or P. aeruginosa (5.00 × 105 CFU/mL) with 10 mL of 100% culture media per bottle. The sample bottles were incubated at 37 ◦C with shaking at 100 rpm for 48 h. Aliquots were taken at 0, 6, 24 and 48 h after inoculation and bacterial numbers were determined as colony-forming units (CFU), as well as by luminescence measurements for S. aureus and P. aeruginosa, at each time point. Luminescence measurements were conducted using a Tecan Infinite M200 Pro Luminometer (Tecan Group Ltd., Männedorf, Switzerland). 3.7. Antimicrobial Efficacy of Aqueous Release Media from PVA-Silver Films The antimicrobial activity of various release media was determined using 96-well plate assays against S. aureus and P. aeruginosa but not against E. coli because tests using PVA-silver films showed that antimicrobial activity was not strong in that case. In each test, 40 μL of LB broth was aliquoted into each well, to which 60 μL of LB broth containing 8.33 × 105 CFU/mL of bacteria was added to give a final bacterial concentration of approximately 5.00 × 105 CFU/mL. The exact starting concentration was verified via CFU counts. Control wells were set up as follows: the bacterial control contained 60 μL of culture in 40 uL of sterile double-distilled water and the negative bacterial control contained 100 μL of sterile double-distilled water only. Following gentle mixing, each 96-well plate was incubated for four hours at 37 ◦C and 120 rpm. At 0, 1, 2, 3, and 4-h time points the luminescence was measured to determine bacterial viability. In addition to luminescence, viable bacteria were also quantified via CFU counts at the 4-h time point to ensure correlation with the luminescence measurements. Aqueous release media from PVA-silver films were obtained at daily intervals up to 10 days. After each sampling, the liquid removed was replaced with an equal volume of fresh nutrient broth. Four 5 mL replicates of each release medium were used for this study. In each case half of the release medium (2.5 mL) was added to bacteria-containing nutrient broth at 33% concentration. Incubation and sampling were then carried out as for the experiments with the controls. 4. Results and Discussion 4.1. Appearance of PVA-Silver Films The probable mechanism of PVA crosslinking using silver and heat is shown in Figure 1. The visual appearance of 5 cm-diameter PVA-silver films after drying and before heat curing, as well as films containing 1%, 3%, or 5% w/w silver nitrate which had been heat cured at various temperatures for 90 min, is shown in Figure 2. All films became light brown in color after overnight drying at 65 ◦C and the color of the films became increasingly darker as the heat-curing temperature increased. The appearance of the same films after immersion in water and constant agitation for one week at 37 ◦C in an incubator shaker is shown in Figure 3. The films that had only been dried and the films dried and heat cured at 80 ◦C for 90 min dissolved rapidly in water; however, the films heat cured at 110 ◦C for 90 min were only partly dissolved after one week and the films heat cured at 140 ◦C for 90 min appeared to remain intact. The aqueous leachate from the films took on a yellow colour, which was particularly noticeable for the films that showed some degree of dissolution in water.PDF Image | Hydrogel Forming Dressings Containing Silver Nanoparticles
PDF Search Title:
Hydrogel Forming Dressings Containing Silver NanoparticlesOriginal File Name Searched:
nanomaterials-11-00096.pdfDIY PDF Search: Google It | Yahoo | Bing
Turbine and System Plans CAD CAM: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. More Info
Waste Heat Power Technology: Organic Rankine Cycle uses waste heat to make electricity, shaft horsepower and cooling. More Info
All Turbine and System Products: Infinity Turbine ORD systems, turbine generator sets, build plans and more to use your waste heat from 30C to 100C. More Info
CO2 Phase Change Demonstrator: CO2 goes supercritical at 30 C. This is a experimental platform which you can use to demonstrate phase change with low heat. Includes integration area for small CO2 turbine, static generator, and more. This can also be used for a GTL Gas to Liquids experimental platform. More Info
Introducing the Infinity Turbine Products Infinity Turbine develops and builds systems for making power from waste heat. It also is working on innovative strategies for storing, making, and deploying energy. More Info
Need Strategy? Use our Consulting and analyst services Infinity Turbine LLC is pleased to announce its consulting and analyst services. We have worked in the renewable energy industry as a researcher, developing sales and markets, along with may inventions and innovations. More Info
Made in USA with Global Energy Millennial Web Engine These pages were made with the Global Energy Web PDF Engine using Filemaker (Claris) software.
Infinity Turbine Developing Spinning Disc Reactor SDR or Spinning Disc Reactors reduce processing time for liquid production of Silver Nanoparticles.
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)