Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds
Chronic wounds fail to heal and are accompanied by an ongoing infection. They cause suffering, shorten lifespans, and their prevalence is increasing. Unfortunately, the medical treatment of chronic wounds has remained unchanged for decades. A novel approach to break the biological vicious cycle is t...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-03-01
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| Series: | Antibiotics |
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| Online Access: | https://www.mdpi.com/2079-6382/10/4/362 |
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| author | Kilian Böttle Krasimir Vasilev Thomas Danny Michl |
| author_facet | Kilian Böttle Krasimir Vasilev Thomas Danny Michl |
| author_sort | Kilian Böttle |
| collection | DOAJ |
| description | Chronic wounds fail to heal and are accompanied by an ongoing infection. They cause suffering, shorten lifespans, and their prevalence is increasing. Unfortunately, the medical treatment of chronic wounds has remained unchanged for decades. A novel approach to break the biological vicious cycle is the long-lived radical (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO). TEMPO can be plasma polymerised (TEMPOpp) into thin coatings that have antimicrobial properties. However, due to its radical nature, quenching causes it to lose effectiveness over time. Our aim in this study was to extend the shelf-life of TEMPOpp coatings using various storage conditions: Namely, room temperature (RT), room temperature & vacuum sealed (RTV), freezer temperature & vacuum sealed (FTV). We have analysed the coatings’ quality via the surface analytical methods of X-Ray Photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR); finding marked differences among the three storage conditions. Furthermore, we have compared the antimicrobial efficacy of the stored coatings against two major bacterial pathogens, <i>Staphylococcus aureus</i> and <i>Staphylococcus epidermidis</i>, commonly found in chronic wounds. We did so both qualitatively via live/dead staining, as well as quantitatively via (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium (XTT) viability assay for up to 15 weeks in 5 weeks increments. Taken all together, we demonstrate that samples stored under FTV conditions retain the highest antimicrobial activity after 15 weeks and that this finding correlates with the retained concentration of nitroxides. |
| first_indexed | 2024-03-10T12:48:48Z |
| format | Article |
| id | doaj.art-dbcdac4be9af48caaa3ba1870298c13c |
| institution | Directory Open Access Journal |
| issn | 2079-6382 |
| language | English |
| last_indexed | 2024-03-10T12:48:48Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Antibiotics |
| spelling | doaj.art-dbcdac4be9af48caaa3ba1870298c13c2023-11-21T13:17:17ZengMDPI AGAntibiotics2079-63822021-03-0110436210.3390/antibiotics10040362Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic WoundsKilian Böttle0Krasimir Vasilev1Thomas Danny Michl2Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, AustraliaFuture Industries Institute, University of South Australia, Mawson Lakes, SA 5095, AustraliaFuture Industries Institute, University of South Australia, Mawson Lakes, SA 5095, AustraliaChronic wounds fail to heal and are accompanied by an ongoing infection. They cause suffering, shorten lifespans, and their prevalence is increasing. Unfortunately, the medical treatment of chronic wounds has remained unchanged for decades. A novel approach to break the biological vicious cycle is the long-lived radical (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO). TEMPO can be plasma polymerised (TEMPOpp) into thin coatings that have antimicrobial properties. However, due to its radical nature, quenching causes it to lose effectiveness over time. Our aim in this study was to extend the shelf-life of TEMPOpp coatings using various storage conditions: Namely, room temperature (RT), room temperature & vacuum sealed (RTV), freezer temperature & vacuum sealed (FTV). We have analysed the coatings’ quality via the surface analytical methods of X-Ray Photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR); finding marked differences among the three storage conditions. Furthermore, we have compared the antimicrobial efficacy of the stored coatings against two major bacterial pathogens, <i>Staphylococcus aureus</i> and <i>Staphylococcus epidermidis</i>, commonly found in chronic wounds. We did so both qualitatively via live/dead staining, as well as quantitatively via (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium (XTT) viability assay for up to 15 weeks in 5 weeks increments. Taken all together, we demonstrate that samples stored under FTV conditions retain the highest antimicrobial activity after 15 weeks and that this finding correlates with the retained concentration of nitroxides.https://www.mdpi.com/2079-6382/10/4/362TEMPOplasma polymerchronic woundshelf-lifeXTTEPR |
| spellingShingle | Kilian Böttle Krasimir Vasilev Thomas Danny Michl Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds Antibiotics TEMPO plasma polymer chronic wound shelf-life XTT EPR |
| title | Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds |
| title_full | Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds |
| title_fullStr | Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds |
| title_full_unstemmed | Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds |
| title_short | Shelf-Life Optimisation of Plasma Polymerised (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPOpp) Coatings; A New Possible Approach to Tackle Infections in Chronic Wounds |
| title_sort | shelf life optimisation of plasma polymerised 2 2 6 6 tetramethylpiperidin 1 yl oxyl tempopp coatings a new possible approach to tackle infections in chronic wounds |
| topic | TEMPO plasma polymer chronic wound shelf-life XTT EPR |
| url | https://www.mdpi.com/2079-6382/10/4/362 |
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