| 1. |
- Ahmed, Naeem, et al.
(författare)
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Effects of Oxygen (O2) Plasma Treatment in Promoting the Germination and Growth of Chili
- 2022
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Ingår i: Plasma chemistry and plasma processing. - : Springer. - 0272-4324 .- 1572-8986. ; 42:1, s. 91-108
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Tidskriftsartikel (refereegranskat)abstract
- In general, seed germination is improved by low-pressure plasma treatment using precursors such as air, nitrogen, O2, and argon, etc. For the first time, low-pressure O2 plasma was used to treat chili seeds in this study. When compared to untreated and vacuum-treated seeds, O2 plasma treatment using the discharge power of 80 W for 60 s significantly improves chili seed germination and growth. The effect of vacuum on the germination and growth of chili seeds was also studied and shown to be negligible. The physical and chemical changes induced by O2 plasma treatment were investigated to understand the plasma treatment to germination improvement. Combinatory etching and chemical modification aided imbibition and increased germination percentage in this O2 plasma treatment on chili seeds. The success of this method has the potential to be scaled up to solve food security issues with seeds that would otherwise struggle to germinate.
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| 2. |
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| 3. |
- Masood, Asad, et al.
(författare)
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Atmospheric Pressure Plasma Polymerisation of D-Limonene and Its Antimicrobial Activity
- 2023
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- Antibacterial coating is necessary to prevent biofilm-forming bacteria from colonising medical tools causing infection and sepsis in patients. The recent coating strategies such as immobilisation of antimicrobial materials and low-pressure plasma polymerisation may require multiple processing steps involving a high-vacuum system and time-consuming process. Some of those have limited efficacy and durability. Here, we report a rapid and one-step atmospheric pressure plasma polymerisation (APPP) of D-limonene to produce nano-thin films with hydrophobic-like properties for antibacterial applications. The influence of plasma polymerisation time on the thickness, surface characteristic, and chemical composition of the plasma-polymerised films was systematically investigated. Results showed that the nano-thin films deposited at 1 min on glass substrate are optically transparent and homogenous, with a thickness of 44.3 ± 4.8 nm, a smooth surface with an average roughness of 0.23 ± 0.02 nm. For its antimicrobial activity, the biofilm assay evaluation revealed a significant 94% decrease in the number of Escherichia coli (E. coli) compared to the control sample. More importantly, the resultant nano-thin films exhibited a potent bactericidal effect that can distort and rupture the membrane of the treated bacteria. These findings provide important insights into the development of bacteria-resistant and biocompatible coatings on the arbitrary substrate in a straightforward and cost-effective route at atmospheric pressure.
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| 4. |
- Masood, Asad, et al.
(författare)
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Atmospheric Pressure Plasma Polymerization of Carvone: A Promising Approach for Antimicrobial Coatings
- 2023
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Ingår i: Coatings. - : Mdpi. - 2079-6412. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- Medical devices are often vulnerable to colonization by nosocomial pathogens (bacteria), leading to infections. Traditional sterilization methods may not always be effective, and as a result, alternative options are being explored to prevent microbial contamination. Recently, scientists are emphasizing using plant-derived essential oils that possess inherent antibacterial properties to produce antimicrobial coatings using plasma polymerization technology carried out at atmospheric pressure (AP). This approach shows promise compared to other coating strategies that need several processing steps, including a high-vacuum system, and are laborious, such as the immobilization of antimicrobial materials on precoated layers in the low-pressure plasma polymerization approach. The present study demonstrates the potential of AP plasma polymerization for producing thin films with excellent antibacterial properties and surface characteristics. The resulting coatings are stable, smooth, and have high wettability, making them ideal for repelling bacteria. The calculated zeta potential and deposition rate for the films are also favorable. These AP plasma-polymerized thin films created from carvone show a reduction rate of more than 90% for Escherichia coli and Staphylococcus aureus bacteria. Our computational docking studies also reveal strong binding interactions between the original carvone monomer and both bacteria. The study suggests that these AP plasma-produced coatings have great potential as antibacterial coatings for biomedical devices.
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| 5. |
- Masood, Asad, et al.
(författare)
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Pulsed plasma polymerisation of Carvone: chemical characterization and enhanced antibacterial properties
- 2022
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Ingår i: Surface Innovations. - : ICE Publishing. - 2050-6252 .- 2050-6260. ; 11:6-7, s. 339-351
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Tidskriftsartikel (refereegranskat)abstract
- The production of suitable coating with excellent antibacterial performance has now become a viable technique for enhancing the functional qualities of various biomedical materials. Here, pulsed plasma polymerisation was used to produce an antibacterial coating from carvone oil of spearmint plant. The coating films have adjustable chemical and physical properties based on the deposition parameter, i.e., duty cycles (DC). The static water contact angle (WCA) values of PW ppCar increase with the increase of DC. FTIR and XPS showed that the molecular structure of the carvone is less fragmented, retaining moieties associated with C-O and C=O when the DC is reduced. These C-O and C=O moieties likely reduced the measured static water contact angle. This surface chemical composition with predominantly C-O and C=O also showed a stronger bactericidal effect, based on the biofilm assay with bacteria (E. coli and S. aureus), compared to those coating with C-C and C-H produced at higher DC. According to the AFM images, the lower DC resulted in smoother and more homogeneous coating than those produced with the higher DC, while FE-SEM images show that when E. coli and S. aureus membranes were attached to the PW ppCar, they ruptured and distorted with a pore created, and that these distortions and ruptures increased as the DC was reduced.
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