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Wells MJ, Currie H, Gordon VD. Physiological Concentrations of Calcium Interact with Alginate and Extracellular DNA in the Matrices of Pseudomonas aeruginosa Biofilms to Impede Phagocytosis by Neutrophils. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:17050-17058. [PMID: 37972353 PMCID: PMC10764079 DOI: 10.1021/acs.langmuir.3c01637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Biofilms are communities of interacting microbes embedded in a matrix of polymer, protein, and other materials. Biofilms develop distinct mechanical characteristics that depend on their predominant matrix components. These matrix components may be produced by microbes themselves or, for infections in vivo, incorporated from the host environment. Pseudomonas aeruginosa (P. aeruginosa) is a human pathogen that forms robust biofilms that extensively tolerate antibiotics and effectively evade clearance by the immune system. Two of the important bacterial-produced polymers in the matrices of P. aeruginosa biofilms are alginate and extracellular DNA (eDNA), both of which are anionic and therefore have the potential to interact electrostatically with cations. Many physiological sites of infection contain significant concentrations of the calcium ion (Ca2+). In this study, we investigate the structural and mechanical impacts of Ca2+ supplementation in alginate-dominated biofilms grown in vitro, and we evaluate the impact of targeted enzyme treatments on clearance by immune cells. We use multiple-particle tracking microrheology to evaluate the changes in biofilm viscoelasticity caused by treatment with alginate lyase or DNase I. For biofilms grown without Ca2+, we correlate a decrease in relative elasticity with increased phagocytic success. However, we find that growth with Ca2+ supplementation disrupts this correlation except in the case where both enzymes are applied. This suggests that the calcium cation may be impacting the microstructure of the biofilm in nontrivial ways. Indeed, confocal laser scanning fluorescence microscopy and scanning electron microscopy reveal unique Ca2+-dependent eDNA and alginate microstructures. Our results suggest that the presence of Ca2+ drives the formation of structurally and compositionally discrete microdomains within the biofilm through electrostatic interactions with the anionic matrix components eDNA and alginate. Further, we observe that these structures serve a protective function as the dissolution of both components is required to render biofilm bacteria vulnerable to phagocytosis by neutrophils.
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Affiliation(s)
- Marilyn J. Wells
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Hailey Currie
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Vernita D. Gordon
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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Van der Meeren L, Efimova I, Demuynck R, Parakhonskiy B, Krysko DV, Skirtach AG. Mechanobiology of Ferroptotic Cancer Cells as a Novel "Eat-Me" Signal: Regulating Efferocytosis through Layer-by-Layer Coating. Adv Healthc Mater 2023; 12:e2301025. [PMID: 37273241 DOI: 10.1002/adhm.202301025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/31/2023] [Indexed: 06/06/2023]
Abstract
The importance of the clearance of dead cells is shown to have a regulatory role for normal tissue homeostasis and for the modulation of immune responses. However, how mechanobiological properties of dead cells affect efferocytosis remains largely unknown. Here, it is reported that the Young's modulus of cancer cells undergoing ferroptosis is reduced. To modulate their Young's modulus a layer-by-layer (LbL) nanocoating is developed. Scanning electron and fluorescence microscopy confirm coating efficiency of ferroptotic cells while atomic force microscopy reveals encapsulation of the dead cells increases their Young's modulus dependent on the number of applied LbL layers which increases their efferocytosis by primary macrophages. This work demonstrates the crucial role of mechanobiology of dead cells in regulating their efferocytosis by macrophages which can be exploited for the development of novel therapeutic strategies for diseases where modulation of efferocytosis can be potentially beneficial and for the design of drug delivery systems for cancer therapy.
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Affiliation(s)
- Louis Van der Meeren
- Nano-BioTechnology Laboratory, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
- Cancer Research Institute Ghent (CRIG), Ghent, 9000, Belgium
| | - Iuliia Efimova
- Cancer Research Institute Ghent (CRIG), Ghent, 9000, Belgium
- Cell Death Investigation and Therapy Laboratory, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, Ghent, 9000, Belgium
| | - Robin Demuynck
- Cancer Research Institute Ghent (CRIG), Ghent, 9000, Belgium
- Cell Death Investigation and Therapy Laboratory, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, Ghent, 9000, Belgium
| | - Bogdan Parakhonskiy
- Nano-BioTechnology Laboratory, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
- Cancer Research Institute Ghent (CRIG), Ghent, 9000, Belgium
| | - Dmitri V Krysko
- Cancer Research Institute Ghent (CRIG), Ghent, 9000, Belgium
- Cell Death Investigation and Therapy Laboratory, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, Ghent, 9000, Belgium
| | - Andre G Skirtach
- Nano-BioTechnology Laboratory, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
- Cancer Research Institute Ghent (CRIG), Ghent, 9000, Belgium
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Zhou X, Wells MJ, Gordon VD. Incorporation of collagen into Pseudomonas aeruginosa and Staphylococcus aureus biofilms impedes phagocytosis by neutrophils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.25.564018. [PMID: 37961328 PMCID: PMC10634824 DOI: 10.1101/2023.10.25.564018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Biofilms are communities of microbes embedded in a matrix of extracellular polymeric substances (EPS). Matrix components can be produced by biofilm organisms and can also originate from the environment and then be incorporated into the biofilm. For example, we have recently shown that collagen, a host-produced protein that is abundant in many different infection sites, can be taken up into the biofilm matrix, altering biofilm mechanics. The biofilm matrix protects bacteria from clearance by the immune system, and some of that protection likely arises from the mechanical properties of the biofilm. Pseudomonas aeruginosa and Staphylococcus aureus are common human pathogens notable for forming biofilm infections in anatomical sites rich in collagen. Here, we show that the incorporation of Type I collagen into P. aeruginosa and S. aureus biofilms significantly hinders phagocytosis of biofilm bacteria by human neutrophils. However, enzymatic treatment with collagenase, which breaks down collagen, can partly or entirely negate the protective effect of collagen and restore the ability of neutrophils to engulf biofilm bacteria. From these findings, we suggest that enzymatic degradation of host materials may be a potential way to compromise biofilm infections and enhance the efficacy of the host immune response without promoting antibiotic resistance. Such an approach might be beneficial both in cases where the infecting species is known and also in cases wherein biofilm components are not readily known, such as multispecies infections or infections by unknown species.
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Affiliation(s)
- Xuening Zhou
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
| | - Marilyn J Wells
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
| | - Vernita D Gordon
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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4
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Wells MJ, Currie H, Gordon VD. Physiological concentrations of calcium interact with alginate and extracellular DNA in the matrices of Pseudomonas aeruginosa biofilms to impede phagocytosis by neutrophils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563605. [PMID: 37961083 PMCID: PMC10634743 DOI: 10.1101/2023.10.23.563605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Biofilms are communities of interacting microbes embedded in a matrix of polymer, protein, and other materials. Biofilms develop distinct mechanical characteristics that depend on their predominant matrix components. These matrix components may be produced by microbes themselves or, for infections in vivo, incorporated from the host environment. Pseudomonas aeruginosa is a human pathogen that forms robust biofilms that extensively tolerate antibiotics and effectively evade clearance by the immune system. Two of the important bacterial-produced polymers in the matrices of P. aeruginosa biofilms are alginate and extracellular DNA (eDNA), both of which are anionic and therefore have the potential to interact electrostatically with cations. Many physiological sites of infection contain significant concentrations of the calcium ion (Ca2+). In this study we investigate the structural and mechanical impacts of Ca2+ supplementation in alginate-dominated biofilms grown in vitro and we evaluate the impact of targeted enzyme treatments on clearance by immune cells. We use multiple particle tracking microrheology to evaluate the changes in biofilm viscoelasticity caused by treatment with alginate lyase and/or DNAse I. For biofilms grown without Ca2+, we correlate a decrease in relative elasticity with increased phagocytic success. However, we find that growth with Ca2+ supplementation disrupts this correlation except in the case where both enzymes are applied. This suggests that the calcium cation may be impacting the microstructure of the biofilm in non-trivial ways. Indeed, confocal laser scanning fluorescence microscopy and scanning electron microscopy reveal unique Ca2+-dependent eDNA and alginate microstructures. Our results suggest that the presence of Ca2+ drives the formation of structurally and compositionally discrete microdomains within the biofilm through electrostatic interactions with the anionic matrix components eDNA and alginate. Further, we observe that these structures serve a protective function as the dissolution of both components is required to render biofilm bacteria vulnerable to phagocytosis by neutrophils.
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Affiliation(s)
- Marilyn J. Wells
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Hailey Currie
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
| | - Vernita D. Gordon
- Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600, Austin, Texas 78712-1192, USA
- Center for Nonlinear Dynamics, The University of Texas at Austin, 2515 Speedway, Stop C1610, Austin, Texas 78712-11993, USA
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Norman Hackerman Building, 100 East 24th St., NHB 4500, Austin, Texas 78712, USA
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Neural Molecular Science Building, 2506 Speedway, Stop A5000, Austin, Texas 78712, USA
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Wells M, Schneider R, Bhattarai B, Currie H, Chavez B, Christopher G, Rumbaugh K, Gordon V. Perspective: The viscoelastic properties of biofilm infections and mechanical interactions with phagocytic immune cells. Front Cell Infect Microbiol 2023; 13:1102199. [PMID: 36875516 PMCID: PMC9978752 DOI: 10.3389/fcimb.2023.1102199] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/24/2023] [Indexed: 02/18/2023] Open
Abstract
Biofilms are viscoelastic materials that are a prominent public health problem and a cause of most chronic bacterial infections, in large part due to their resistance to clearance by the immune system. Viscoelastic materials combine both solid-like and fluid-like mechanics, and the viscoelastic properties of biofilms are an emergent property of the intercellular cohesion characterizing the biofilm state (planktonic bacteria do not have an equivalent property). However, how the mechanical properties of biofilms are related to the recalcitrant disease that they cause, specifically to their resistance to phagocytic clearance by the immune system, remains almost entirely unstudied. We believe this is an important gap that is ripe for a large range of investigations. Here we present an overview of what is known about biofilm infections and their interactions with the immune system, biofilm mechanics and their potential relationship with phagocytosis, and we give an illustrative example of one important biofilm-pathogen (Pseudomonas aeruginosa) which is the most-studied in this context. We hope to inspire investment and growth in this relatively-untapped field of research, which has the potential to reveal mechanical properties of biofilms as targets for therapeutics meant to enhance the efficacy of the immune system.
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Affiliation(s)
- Marilyn Wells
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
| | - Rebecca Schneider
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Bikash Bhattarai
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, United States
| | - Hailey Currie
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
| | - Bella Chavez
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
| | - Gordon Christopher
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, United States
| | - Kendra Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Vernita Gordon
- Department of Physics, Center for Nonlinear Dynamics, The University of Texas at Austin, Austin, TX, United States
- LaMontagne Center for Infectious Disease, The University of Texas at Austin, Austin, TX, United States
- Interdisciplinary Life Sciences Graduate Program, The University of Texas at Austin, Austin, TX, United States
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6
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Moreau A, Mukherjee S, Yan J. Mechanical Characterization and Single‐Cell Imaging of Bacterial Biofilms. Isr J Chem 2023. [DOI: 10.1002/ijch.202200075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Alexis Moreau
- Department of Molecular, Cellular and Developmental Biology, Quantitative Biology Institute Yale University 260 Whitney Ave. New Haven CT 06511 USA
| | - Sampriti Mukherjee
- Department of Molecular Genetics & Cell Biology University of Chicago 920 E. 58th Street, Suite 1106 Chicago IL 60637
| | - Jing Yan
- Department of Molecular, Cellular and Developmental Biology, Quantitative Biology Institute Yale University 260 Whitney Ave. New Haven CT 06511 USA
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Bakhtiari LA, Wells MJ, Gordon VD. High-throughput assays show the timescale for phagocytic success depends on the target toughness. BIOPHYSICS REVIEWS 2021; 2:031402. [PMID: 34632456 PMCID: PMC8485781 DOI: 10.1063/5.0057071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/07/2021] [Indexed: 11/14/2022]
Abstract
Phagocytic immune cells can clear pathogens from the body by engulfing them. Bacterial biofilms are communities of bacteria that are bound together in a matrix that gives biofilms viscoelastic mechanical properties that do not exist for free-swimming bacteria. Since a neutrophil is too small to engulf an entire biofilm, it must be able to detach and engulf a few bacteria at a time if it is to use phagocytosis to clear the infection. We recently found a negative correlation between the target elasticity and phagocytic success. That earlier work used time-consuming, manual analysis of micrographs of neutrophils and fluorescent beads. Here, we introduce and validate flow cytometry as a fast and high-throughput technique that increases the number of neutrophils analyzed per experiment by two orders of magnitude, while also reducing the time required to do so from hours to minutes. We also introduce the use of polyacrylamide gels in our assay for engulfment success. The tunability of polyacrylamide gels expands the mechanical parameter space we can study, and we find that high toughness and yield strain, even with low elasticity, also impact the phagocytic success as well as the timescale thereof. For stiff gels with low-yield strain, and consequent low toughness, phagocytic success is nearly four times greater when neutrophils are incubated with gels for 6 h than after only 1 h of incubation. In contrast, for soft gels with high-yield strain and consequent high toughness, successful engulfment is much less time-sensitive, increasing by less than a factor of two from 1 to 6 h incubation.
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8
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Dunn MJ, Fillinger RJ, Anderson LM, Anderson MZ. Automated quantification of Candida albicans biofilm-related phenotypes reveals additive contributions to biofilm production. NPJ Biofilms Microbiomes 2020; 6:36. [PMID: 33037223 PMCID: PMC7547077 DOI: 10.1038/s41522-020-00149-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/11/2020] [Indexed: 12/15/2022] Open
Abstract
Biofilms are organized communities of microbial cells that promote persistence among bacterial and fungal species. Biofilm formation by host-associated Candida species of fungi occurs on both tissue surfaces and implanted devices, contributing to host colonization and disease. In C. albicans, biofilms are built sequentially by adherence of yeast to a surface, invasion into the substrate, the formation of aerial hyphal projections, and the secretion of extracellular matrix. Measurement of these biofilm-related phenotypes remains highly qualitative and often subjective. Here, we designed an informatics pipeline for quantifying filamentation, adhesion, and invasion of Candida species on solid agar media and utilized this approach to determine the importance of these component phenotypes to C. albicans biofilm production. Characterization of 23 C. albicans clinical isolates across three media and two temperatures revealed a wide range of phenotypic responses among isolates in any single condition. Media profoundly altered all biofilm-related phenotypes among these isolates, whereas temperature minimally impacted these traits. Importantly, the extent of biofilm formation correlated significantly with the additive score for its component phenotypes under some conditions, experimentally linking the strength of each component to biofilm mass. In addition, the response of the genome reference strain, SC5314, across these conditions was an extreme outlier compared to all other strains, suggesting it may not be representative of the species. Taken together, development of a high-throughput, unbiased approach to quantifying Candida biofilm-related phenotypes linked variability in these phenotypes to biofilm production and can facilitate genetic dissection of these critical processes to pathogenesis in the host.
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Affiliation(s)
- Matthew J Dunn
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Robert J Fillinger
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Leah M Anderson
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA
| | - Matthew Z Anderson
- Department of Microbiology, The Ohio State University, Columbus, OH, 43210, USA.
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, 43210, USA.
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Amin Yavari S, Castenmiller SM, van Strijp JAG, Croes M. Combating Implant Infections: Shifting Focus from Bacteria to Host. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002962. [PMID: 32914481 DOI: 10.1002/adma.202002962] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/28/2020] [Indexed: 05/06/2023]
Abstract
The widespread use of biomaterials to support or replace body parts is increasingly threatened by the risk of implant-associated infections. In the quest for finding novel anti-infective biomaterials, there generally has been a one-sided focus on biomaterials with direct antibacterial properties, which leads to excessive use of antibacterial agents, compromised host responses, and unpredictable effectiveness in vivo. This review sheds light on how host immunomodulation, rather than only targeting bacteria, can endow biomaterials with improved anti-infective properties. How antibacterial surface treatments are at risk to be undermined by biomaterial features that dysregulate the protection normally provided by critical immune cell subsets, namely, neutrophils and macrophages, is discussed. Accordingly, how the precise modification of biomaterial surface biophysical cues, or the incorporation of immunomodulatory drug delivery systems, can render biomaterials with the necessary immune-compatible and immune-protective properties to potentiate the host defense mechanisms is reviewed. Within this context, the protective role of host defense peptides, metallic particles, quorum sensing inhibitors, and therapeutic adjuvants is discussed. The highlighted immunomodulatory strategies may lay a foundation to develop anti-infective biomaterials, while mitigating the increasing threat of antibacterial drug resistance.
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Affiliation(s)
- Saber Amin Yavari
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
| | - Suzanne M Castenmiller
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
| | - Michiel Croes
- Department of Orthopedics, University Medical Center Utrecht, Utrecht, 3508GA, The Netherlands
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