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Wójtowicz D, Stodolak-Zych E. Strategies to Mitigate Biofouling of Nanocomposite Polymer-Based Membranes in Contact with Blood. MEMBRANES 2023; 13:762. [PMID: 37755184 PMCID: PMC10536434 DOI: 10.3390/membranes13090762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/21/2023] [Accepted: 08/25/2023] [Indexed: 09/28/2023]
Abstract
An extracorporeal blood purification method called continuous renal replacement therapy uses a porous hollow-fiber polymeric membrane that is exposed to prolonged contact with blood. In that condition, like with any other submerged filtration membrane, the hemofilter loses its properties over time and use resulting in a rapid decline in flux. The most significant reason for this loss is the formation of a biofilm. Protein, blood cells and bacterial cells attach to the membrane surface in complex and fluctuating processes. Anticoagulation allows for longer patency of vascular access and a longer lifespan of the membrane. Other preventive measures include the modification of the membrane itself. In this article, we focused on the role of nanoadditives in the mitigation of biofouling. Nanoparticles such as graphene, carbon nanotubes, and silica effectively change surface properties towards more hydrophilic, affect pore size and distribution, decrease protein adsorption and damage bacteria cells. As a result, membranes modified with nanoparticles show better flow parameters, longer lifespan and increased hemocompatibility.
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Affiliation(s)
- Dominika Wójtowicz
- Department of Biomaterials and Composites, Faculty of Materials Science and Ceramics, AGH University of Krakow, Al. Mickiewicza 30, 30-059 Krakow, Poland;
- Clinical Department of Anaesthesiology and Intensive Care, University Hospital in Krakow, ul. Jakubowskiego 2, 30-688 Krakow, Poland
| | - Ewa Stodolak-Zych
- Department of Biomaterials and Composites, Faculty of Materials Science and Ceramics, AGH University of Krakow, Al. Mickiewicza 30, 30-059 Krakow, Poland;
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An H, Tian T, Wang Z, Jin R, Zhou J. Role of extracellular polymeric substances in the immobilization of hexavalent chromium by Shewanella putrefaciens CN32 unsaturated biofilms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 810:151184. [PMID: 34699809 DOI: 10.1016/j.scitotenv.2021.151184] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Microbial remediation provides a promising avenue for the management and restoration of heavy metal-contaminated soils. Microorganisms in soils usually exist within unsaturated biofilms, however, their response to heavy metals is still limited compared to saturated biofilms. This work investigated the Cr(VI) immobilization by Shewanella putrefaciens CN32 unsaturated biofilms, and explored the underlying mechanisms of Cr(VI) complexation. Results reveal a dose-dependent toxicity of Cr(VI) to the growth of the unsaturated biofilms. During the early growth stage, the Cr(VI) addition stimulated more extracellular polymeric substances (EPS) production. In the meantime, the EPS were demonstrated to be the primary components for Cr(VI) immobilization, which accounted for more than 60% of the total adsorbed Cr(VI). The Fourier transform infrared spectra and X-ray photoelectron spectra corroborated that the binding sites for immobilizing Cr(VI) were hydroxyl, carboxyl, phosphoryl and amino functional groups of the proteins and polysaccharides in EPS. However, for the starved unsaturated biofilms, EPS were depleted and the EPS-bound Cr(VI) were released, which caused approximately 60% of the adsorbed Cr(VI) onto cell components and further aggravated the Cr(VI) stress to cells. This work extends our understanding about the Cr(VI) immobilization by unsaturated biofilms, and provides useful information for remediation of heavy metal-contaminated soils.
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Affiliation(s)
- Hui An
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Tian Tian
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Ziting Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Ruofei Jin
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environment Science and Technology, Dalian University of Technology, Dalian 116024, China
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Wi YM, Patel R. Understanding Biofilms and Novel Approaches to the Diagnosis, Prevention, and Treatment of Medical Device-Associated Infections. Infect Dis Clin North Am 2018; 32:915-929. [PMID: 30241715 DOI: 10.1016/j.idc.2018.06.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Treatment of medical device-related infections is challenging and recurrence is common. The main reason for this is that microorganisms adhere to the surfaces of medical devices and enter into a biofilm state in which they display distinct growth rates, structural features, and protection from antimicrobial agents and host immune mechanisms compared with their planktonic counterparts. This article reviews how microorganisms form biofilms and the mechanisms of protection against antimicrobial agents and the host immune system provided by biofilms. Also discussed are innovative strategies for the diagnosis of biofilm-associated infection and novel approaches to treatment and prevention of medical device-associated infections.
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Affiliation(s)
- Yu Mi Wi
- Division of Infectious Diseases, Department of Internal Medicine, Samsung Changwon Hospital, Sungkyunkwan University, 158 palyong-ro, MasanHoiwon-gu, Changwon-si, Gyeongsangnam-do 51353, Korea
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA; Division of Infectious Diseases, Department of Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.
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Scalise A, Bianchi A, Tartaglione C, Bolletta E, Pierangeli M, Torresetti M, Marazzi M, Di Benedetto G. Microenvironment and microbiology of skin wounds: the role of bacterial biofilms and related factors. Semin Vasc Surg 2016; 28:151-9. [PMID: 27113281 DOI: 10.1053/j.semvascsurg.2016.01.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Wound healing is a systemic response to injury that impacts the entire body and not just the site of tissue damage; it represents one of the most complex biological processes. Our knowledge of wound healing continues to evolve and it is now clear that the wound microenvironment plays a crucial role. The interactions between cells and the surface microenvironment, referred to as the "biofilm," contributes to skin homeostasis and healing. Understanding the functional complexity of the wound microenvironment informs how various factors such as age, ischemia, or bacterial infections can impair or arrest the normal healing processes, and it also allows for the possibility of acting therapeutically on healing defects with microenvironment manipulation. Microbes represent a particularly important factor for influencing the wound microenvironment and therefore wound healing. Moreover, the role of infections, particularly those that are sustained by biofilm-forming bacteria, is mutually related to other microenvironment aspects, such as humidity, pH, metalloproteinases, and reactive oxygen species, on which the modern research of new therapeutic strategies is focused. Today, chronic wounds are a rapidly growing health care burden and it is progressively understood that many non-healing wounds might benefit from therapies that target microorganisms and their biofilm communities. There is no doubt that host factors like perfusion impairments, venous insufficiency, pressure issues, malnutrition, and comorbidities strongly impact the healing processes and therefore must be targeted in the therapeutic management, but this approach might be not enough. In this article, we detail how bacterial biofilms and related factors impair wound healing, the reasons they must be considered a treatment target that is as important as the host's local and systemic pathologic conditions, and the latest therapeutic strategies derived from the comprehension of the wound microenvironment.
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Affiliation(s)
- A Scalise
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy.
| | - A Bianchi
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy
| | - C Tartaglione
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy
| | - E Bolletta
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy
| | - M Pierangeli
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy
| | - M Torresetti
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy
| | - M Marazzi
- Struttura Semplice Terapia Tissutale, A.O. Ospedale Niguarda Ca׳ Granda, Milan, Italy
| | - G Di Benedetto
- Department of Plastic and Reconstructive Surgery, Università Politecnica delle, Marche, Ancona, Italy
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Saraswathi P, Beuerman RW. Corneal Biofilms: From Planktonic to Microcolony Formation in an Experimental Keratitis Infection with Pseudomonas Aeruginosa. Ocul Surf 2015. [DOI: 10.1016/j.jtos.2015.07.001 [pii]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Saraswathi P, Beuerman RW. Corneal Biofilms: From Planktonic to Microcolony Formation in an Experimental Keratitis Infection with Pseudomonas Aeruginosa. Ocul Surf 2015. [PMID: 26220579 DOI: 10.1016/j.jtos.2015.07.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE Microbial biofilms commonly comprise part of the infectious scenario, complicating the therapeutic approach. The purpose of this study was to determine in a mouse model of corneal infection if mature biofilms formed and to visualize the stages of biofilm formation. METHODS A bacterial keratitis model was established using Pseudomonas aeruginosa ATCC 9027 (1 × 10(8) CFU/ml) to infect the cornea of C57BL/6 black mouse. Eyes were examined post-infection (PI) on days 1, 2, 3, 5, and 7, and imaged by slit lamp microscopy, and light, confocal, and electron microscopy to identify the stages of biofilm formation and the time of appearance. RESULTS On PI day 1, Gram staining showed rod-shaped bacteria adherent on the corneal surface. On PI days 2 and 3, bacteria were seen within webs of extracellular polymeric substance (EPS) and glycocalyx secretion, imaged by confocal microscopy. Scanning electron microscopy demonstrated microcolonies of active infectious cells bound with thick fibrous material. Transmission electron microscopy substantiated the formation of classical biofilm architecture with P. aeruginosa densely packed within the extracellular polymeric substances on PI days 5 and 7. CONCLUSION Direct visual evidence showed that biofilms routinely developed on the biotic surface of the mouse cornea. The mouse model can be used to develop new approaches to deal therapeutically with biofilms in corneal infections.
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Affiliation(s)
| | - Roger W Beuerman
- Singapore Eye Research Institute (SERI), Singapore; Duke-NUS SRP Neuroscience and Behavioural Disorders and Emerging Infectious Diseases, Singapore; Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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Abstract
Prosthetic joint infection (PJI) still remains a significant problem. In line with the forecasted rise in joint replacement procedures, the number of cases of PJI is also anticipated to rise. The formation of biofilm by causative pathogens is central to the occurrence and the recalcitrance of PJI. The subject of microbial biofilms is receiving increasing attention, probably as a result of the wide acknowledgement of the ubiquity of biofilms in the natural, industrial, and clinical contexts, as well as the notorious difficulty in eradicating them. In this review, we discuss the pertinent issues surrounding PJI and the challenges posed by biofilms regarding diagnosis and treatment. In addition, we discuss novel strategies of prevention and treatment of biofilm-related PJI.
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Affiliation(s)
| | | | - Jason C Webb
- Avon Orthopedic Centre, Southmead Hospital,University of Bristol
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Kanmani S, Gandhimathi R, Muthukkumaran K. Bioclogging in porous media: influence in reduction of hydraulic conductivity and organic contaminants during synthetic leachate permeation. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE & ENGINEERING 2014; 12:126. [PMID: 25400936 PMCID: PMC4229613 DOI: 10.1186/s40201-014-0126-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/14/2014] [Indexed: 06/04/2023]
Abstract
In this study the concept of biofilm accumulation in the sand column was promoted to assess the changes in hydraulic conductivity and concentration of organic contaminants of the synthetic leachate. Four different combinations of column study were carried out using synthetic leachate as a substrate solution. Mixed and stratified mode of experiments with two different sizes (0.3 mm and 0.6 mm) of sand grains were used for column filling. Two columns were acting as a blank, the remaining two columns amended with mixed microbial cultures which were isolated from leachate. The column was operated with continuous synthetic leachate supply for 45 days. The results indicated that the highest hydraulic conductivity reduction occurred in the mixed sand microbial column with 98.8% when compared to stratified sand microbial column. The analysis of organic contaminants of the effluent leachate was also clearly shown that the mixed sand amended with microbes poses a suitable remedial measure when compared to natural and synthetic liners for controlling the leachate migration in the subsurface environment.
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Affiliation(s)
- Subramaniam Kanmani
- Department of Civil Engineering, National Institute of Technology, Tiruchirappalli, Tamilnadu, India
| | - Rajan Gandhimathi
- Department of Civil Engineering, National Institute of Technology, Tiruchirappalli, Tamilnadu, India
| | - Kasinathan Muthukkumaran
- Department of Civil Engineering, National Institute of Technology, Tiruchirappalli, Tamilnadu, India
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Walker J, Jhutty A, Parks S, Willis C, Copley V, Turton J, Hoffman P, Bennett A. Investigation of healthcare-acquired infections associated with Pseudomonas aeruginosa biofilms in taps in neonatal units in Northern Ireland. J Hosp Infect 2014; 86:16-23. [DOI: 10.1016/j.jhin.2013.10.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/03/2013] [Indexed: 11/25/2022]
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Arevalos-Sánchez M, Regalado C, Martin S, Meas-Vong Y, Cadena-Moreno E, García-Almendárez B. Effect of neutral electrolyzed water on lux-tagged Listeria monocytogenes EGDe biofilms adhered to stainless steel and visualization with destructive and non-destructive microscopy techniques. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.05.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bridier A, Meylheuc T, Briandet R. Realistic representation of Bacillus subtilis biofilms architecture using combined microscopy (CLSM, ESEM and FESEM). Micron 2013; 48:65-9. [PMID: 23517761 DOI: 10.1016/j.micron.2013.02.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/25/2013] [Accepted: 02/25/2013] [Indexed: 11/20/2022]
Abstract
In this contribution, we used a set of microscopic techniques including confocal laser scanning microscopy (CLSM), environmental scanning electron microscopy (ESEM) and field emission scanning electron microscopy (FESEM) to analyze the three-dimensional spatial arrangement of cells and their surrounding matrix in Bacillus subtilis biofilm. The combination of the different techniques enabled a deeper and realistic deciphering of biofilm architecture by providing the opportunity to overcome the limits of each single technique.
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Affiliation(s)
- A Bridier
- INRA, UMR 1319 Micalis, F-78350 Jouy-en-Josas, France
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Percival SL, Hill KE, Williams DW, Hooper SJ, Thomas DW, Costerton JW. A review of the scientific evidence for biofilms in wounds. Wound Repair Regen 2012; 20:647-57. [DOI: 10.1111/j.1524-475x.2012.00836.x] [Citation(s) in RCA: 317] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
| | - Katja E. Hill
- School of Dentistry; Cardiff University; Cardiff; United Kingdom
| | | | - Samuel J. Hooper
- School of Dentistry; Cardiff University; Cardiff; United Kingdom
| | - Dave W. Thomas
- School of Dentistry; Cardiff University; Cardiff; United Kingdom
| | - John W. Costerton
- Center for Genomic Sciences; Allegheny-Singer Research Institute; Pittsburgh; Pennsylvania
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Lawson MC, Hoth KC, DeForest CA, Bowman CN, Anseth KS. Inhibition of Staphylococcus epidermidis biofilms using polymerizable vancomycin derivatives. Clin Orthop Relat Res 2010; 468:2081-91. [PMID: 20191335 PMCID: PMC2895847 DOI: 10.1007/s11999-010-1266-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Biofilm formation on indwelling medical devices is a ubiquitous problem causing considerable patient morbidity and mortality. In orthopaedic surgery, this problem is exacerbated by the large number and variety of material types that are implanted. Metallic hardware in conjunction with polymethylmethacrylate (PMMA) bone cement is commonly used. QUESTIONS/PURPOSES We asked whether polymerizable derivatives of vancomycin might be useful to (1) surface modify Ti-6Al-4V alloy and to surface/bulk modify PMMA bone cement to prevent Staphylococcus epidermidis biofilm formation and (2) whether the process altered the compressive modulus, yield strength, resilience, and/or fracture strength of cement copolymers. METHODS A Ti-6Al-4V alloy was silanized with methacryloxypropyltrimethoxysilane in preparation for subsequent polymer attachment. Surfaces were then coated with polymers formed from PEG(375)-acrylate or a vancomycin-PEG(3400)-PEG(375)-acrylate copolymer. PMMA was loaded with various species, including vancomycin and several polymerizable vancomycin derivatives. To assess antibiofilm properties of these materials, initial bacterial adherence to coated Ti-6Al-4V was determined by scanning electron microscopy (SEM). Biofilm dry mass was determined on PMMA coupons; the compressive mechanical properties were also determined. RESULTS SEM showed the vancomycin-PEG(3400)-acrylate-type surface reduced adherent bacteria numbers by approximately fourfold when compared with PEG(375)-acrylate alone. Vancomycin-loading reduced all mechanical properties tested; in contrast, loading a vancomycin-acrylamide derivative restored these deficits but demonstrated no antibiofilm properties. A polymerizable, PEGylated vancomycin derivative reduced biofilm attachment but resulted in inferior cement mechanical properties. CLINICAL RELEVANCE The approaches presented here may offer new strategies for developing biofilm-resistant orthopaedic materials. Specifically, polymerizable derivatives of traditional antibiotics may allow for direct polymerization into existing materials such as PMMA bone cement while minimizing mechanical property compromise. Questions remain regarding ideal monomer structure(s) that confer biologic and mechanical benefits.
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Affiliation(s)
- McKinley C. Lawson
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO USA
- Medical Scientist Training Program (MD/PhD Program), University of Colorado School of Medicine, Denver, CO USA
- University of Colorado School of Medicine, UCHSC MSTP Mailstop B176, Academic Office One, Room L15-2601, 12631 E 17th Avenue, Aurora, CO 80045 USA
| | - Kevin C. Hoth
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO USA
| | - Cole A. DeForest
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO USA
| | - Christopher N. Bowman
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO USA
| | - Kristi S. Anseth
- Department of Chemical and Biological Engineering, Howard Hughes Medical Institute, University of Colorado, 424 UCB, Boulder, CO 80309 USA
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Clarke S, Mielke RE, Neal A, Holden P, Nadeau JL. Bacterial and mineral elements in an arctic biofilm: a correlative study using fluorescence and electron microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2010; 16:153-165. [PMID: 20100386 DOI: 10.1017/s1431927609991334] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Few simple labeling methods exist for simultaneous fluorescence and electron microscopy of bacteria and biofilms. Here we describe the synthesis, characterization, and application of fluorescent nanoparticle quantum dot (QD) conjugates to target microbial species, including difficult to label Gram-negative strains. These QD conjugates impart contrast for both environmental scanning electron microscopy (ESEM) and fluorescence microscopy, permitting observation of living and fixed bacteria and biofilms. We apply these probes for studying biofilms extracted from perennial cold springs in the Canadian High Arctic, which is a particularly challenging system. In these biofilms, sulfur-metabolizing bacteria live in close association with unusual sulfur mineral formations. Following simple labeling protocols with the QD conjugates, we are able to image these organisms in fully-hydrated samples and visualize their relationship to the sulfur minerals using both ESEM and fluorescence microscopy. We then use scanning transmission electron microscopy to observe precipitated sulfur around individual cells and within the biofilm lattice. All combined, this information sheds light on the possible mechanisms of biofilm and mineral structure formation. These new QD conjugates and techniques are highly transferable to many other microbiological applications, especially those involving Gram-negative bacteria, and can be used for correlated fluorescence and electron microscopy.
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Affiliation(s)
- Samuel Clarke
- Department of Biomedical Engineering, McGill University, Montréal, Canada
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Priester JH, Horst AM, Van de Werfhorst LC, Saleta JL, Mertes LAK, Holden PA. Enhanced visualization of microbial biofilms by staining and environmental scanning electron microscopy. J Microbiol Methods 2006; 68:577-87. [PMID: 17196692 DOI: 10.1016/j.mimet.2006.10.018] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 10/28/2006] [Indexed: 11/29/2022]
Abstract
Bacterial biofilms, i.e. surface-associated cells covered in hydrated extracellular polymeric substances (EPS), are often studied with high-resolution electron microscopy (EM). However, conventional desiccation and high vacuum EM protocols collapse EPS matrices which, in turn, deform biofilm appearances. Alternatively, wet-mode environmental scanning electron microscopy (ESEM) is performed under a moderate vacuum and without biofilm drying. If completely untreated, however, EPS is not electron dense and thus is not resolved well in ESEM. Therefore, this study was towards adapting several conventional SEM staining protocols for improved resolution of biofilms and EPS using ESEM. Three different biofilm types were used: 1) Pseudomonas aeruginosa unsaturated biofilms cultured on membranes, 2) P. aeruginosa cultured in moist sand, and 3) mixed community biofilms cultured on substrates in an estuary. Working with the first specimen type, a staining protocol using ruthenium red, glutaraldehyde, osmium tetroxide and lysine was optimized for best topographic resolution. A quantitative image analysis tool that maps relief, newly adopted here for studying biofilms, was used to compare micrographs. When the optimized staining and ESEM protocols were applied to moist sand cultures and aquatic biofilms, the smoothening effect that bacterial biofilms have on rough sand, and the roughening that aquatic biofilms impart on initially smooth coupons, were each quantifiable. This study thus provides transferable staining and ESEM imaging protocols suitable for a wide range of biofilms, plus a novel tool for quantifying biofilm image data.
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Affiliation(s)
- John H Priester
- Donald Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106-5131, USA
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Verran J. Biofouling in Food Processing: Biofilm or Biotransfer Potential? FOOD AND BIOPRODUCTS PROCESSING 2002. [DOI: 10.1205/096030802321154808] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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