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Maggay IV, Liao TY, Venault A, Lin HT, Chao CC, Wei TC, Chang Y. Leveraging the Dielectric Barrier Discharge Plasma Process to Create Regenerative Biocidal ePTFE Membranes. ACS APPLIED MATERIALS & INTERFACES 2023; 15:48001-48014. [PMID: 37787514 DOI: 10.1021/acsami.3c10800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
The utilization of dielectric barrier discharge (DBD) plasma treatment for modifying substrate surfaces constitutes an easy and simple approach with a potential for diverse applications. This technique was used to modify the surface of a commercial porous expanded poly(tetrafluoroethylene) (ePTFE) film with either dimethylaminoethyl methacrylate (DMAEMA) or (trimethylamino)ethyl methacrylate chloride (TMAEMA) monomers, aiming to obtain antibacterial ePTFE. Physicochemical analyses of the membranes revealed that DBD successfully enhanced the surface energy and surface charge of the membranes while maintaining high porosity (>75%) and large pore size (>1.0 μm). Evaluation of the bacteria killing-releasing (K-R) function revealed that both DMAEMA and TMAEMA endowed ePTFE with the ability to kill Escherichia coli bacteria. However, only TMAEMA-grafted ePTFE allowed for the release of dead bacteria from the surface upon washing with sodium hexametaphosphate (SHMP) saline solution, owing to its cationic charge derived from the quaternary amine. Washing with SHMP disturbed the electrostatic force between the polymer brushes and dead bacteria, which caused the release of the dead bacteria. Lastly, dead-end bacteria filtration showed that the TMAEMA-grafted ePTFE was able to kill 99.78% of the bacteria, while approximately 61.55% of bacteria were killed upon contact. The present findings support the feasibility of using DBD plasma treatment for designing surfaces that target bacteria and aid in the containment of disease-causing pathogens.
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Affiliation(s)
- Irish Valerie Maggay
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chungli 32023, Taiwan, R.O.C
| | - Ting-Yu Liao
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chungli 32023, Taiwan, R.O.C
| | - Antoine Venault
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chungli 32023, Taiwan, R.O.C
| | - Hao-Tung Lin
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chungli 32023, Taiwan, R.O.C
| | - Chih-Cheng Chao
- Tasheh Biotec Co., LTD, 226, Yuan-Pei Street, Hsinchu City 300, Taiwan, R.O.C
| | - Ta-Chin Wei
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chungli 32023, Taiwan, R.O.C
| | - Yung Chang
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chungli 32023, Taiwan, R.O.C
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Kookana RS, Williams M, Gregg A, Semmler A, Du J, Apte SC. Sorption, degradation and microbial toxicity of chemicals associated with hydraulic fracturing fluid and produced water in soils. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119754. [PMID: 35835270 DOI: 10.1016/j.envpol.2022.119754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/28/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Spills of hydraulic fracturing (HF) fluids and of produced water during unconventional gas extraction operations may cause soil contamination. We studied the degradation and microbial toxicity of selected HF chemical components including two biocides (methylisothiozolinone- MIT, chloromethylisothiozolinone- CMIT), a gel-breaker aid (triethanolamine -TEA), and three geogenic chemicals (phenol, m-cresol and p-cresol) in ultrapure water, HF fluid and produced water in five different soil types (surface and subsurface soils). The degradation of the two biocides (in soils treated with HF fluid or ultrapure water) and of the three geogenic chemicals (in soils treated with produced water) was rapid (in all cases DT50 values < 2 days in surface soils). In contrast, the loss of TEA was much slower in soils, especially in those treated with HF fluid (DT50 > 30 days). Sorption coefficients (Koc in L/Kg) in these soils ranged from 71 to 733 for TEA, 64-408 for MIT and 11-72 for CMIT. In terms of soil microbial toxicity, exposure to HF fluid and produced water reduced microbial respiration, albeit temporarily. The overall microbial activities in surface soils contaminated with produced water had fully recovered in most soils. In contrast, the HF fluid addition to soils completely inhibited the nitrification in all soils, with little recovery over the 60 day experimental period. In the case of produced water exposure, three out of five surface soils showed complete recovery in nitrification during the study period. The functional genes for nitrogen fixation (nifH) and carbon cycling (GA1) and microbial community composition (16 S rRNA) were significantly affected by HF fluid in some soils. Overall, the study shows that the HF fluid can have significant detrimental impact on soil microbial functions, especially on nitrogen cycling. More work is needed to identify the exact cause of microbial toxicity in soils contaminated with HF fluid.
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Affiliation(s)
- Rai S Kookana
- CSIRO Land and Water, Locked Bag 2, Glen Osmond, SA, 5064, Australia; University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia.
| | - Mike Williams
- CSIRO Land and Water, Locked Bag 2, Glen Osmond, SA, 5064, Australia.
| | - Adrienne Gregg
- CSIRO Land and Water, Locked Bag 2, Glen Osmond, SA, 5064, Australia.
| | - Adelle Semmler
- CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA, 5064, Australia.
| | - Jun Du
- CSIRO Land and Water, Locked Bag 2, Glen Osmond, SA, 5064, Australia.
| | - Simon C Apte
- CSIRO Land and Water, Locked Bag 2007, Kirrawee, NSW, 2232, Australia.
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Comparative Analysis of the Mechanism of Resistance to Silver Nanoparticles and the Biocide 2,2-Dibromo-3-Nitrilopropionamide. Antimicrob Agents Chemother 2022; 66:e0203121. [PMID: 35604211 DOI: 10.1128/aac.02031-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobials such as nanoparticles and biocides are used to control microbial growth. We used Escherichia coli to study the process of acquired resistance to silver nanoparticles (Ag-NP) and the industrial biocide DBNPA when grown in sub-MICs. We determined the MICs of these two antimicrobials against E. coli. We then performed an experimental evolution study where E. coli was grown in subinhibitory concentrations of the antimicrobials and transferred 10 times. We then tracked the changes in growth characteristics, lactate dehydrogenase (LDH) activity, reactive oxidative species (ROS) production, and the role of efflux pumps in conferring resistance. We also performed genome sequencing to determine the genetic basis for acquired resistance. Our results showed that E. coli could rapidly develop resistance to Ag-NP and DBNPA after growth in low concentrations of the antimicrobials. The expression of efflux pumps plays a vital role in both Ag-NP and DBNPA resistance. Multiple mutations occurred in the adapted strains that may confer resistance to both Ag-NP and DBNPA. Our study provides insights into mechanisms of adaptation and resistance to antimicrobials. Our results suggest that there are some shared mechanisms to resist nanoparticles and biocides as well as some key differences. The mechanism of resistance to Ag-NP might be related to flagellin production, while efflux pumps seem to be associated with resistance to DBNPA. This work provides a comparative study of the mechanisms of acquired resistance to these two types of antimicrobials.
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