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Pham LHP, Ly KL, Colon-Ascanio M, Ou J, Wang H, Lee SW, Wang Y, Choy JS, Phillips KS, Luo X. Dissolvable alginate hydrogel-based biofilm microreactors for antibiotic susceptibility assays. Biofilm 2023; 5:100103. [PMID: 36691521 PMCID: PMC9860113 DOI: 10.1016/j.bioflm.2022.100103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/28/2022] [Accepted: 12/28/2022] [Indexed: 01/11/2023] Open
Abstract
Biofilms are found in many infections in the forms of surface-adhering aggregates on medical devices, small clumps in tissues, or even in synovial fluid. Although antibiotic resistance genes are studied and monitored in the clinic, the structural and phenotypic changes that take place in biofilms can also lead to significant changes in how bacteria respond to antibiotics. Therefore, it is important to better understand the relationship between biofilm phenotypes and resistance and develop approaches that are compatible with clinical testing. Current methods for studying antimicrobial susceptibility are mostly planktonic or planar biofilm reactors. In this work, we develop a new type of biofilm reactor-three-dimensional (3D) microreactors-to recreate biofilms in a microenvironment that better mimics those in vivo where bacteria tend to form surface-independent biofilms in living tissues. The microreactors are formed on microplates, treated with antibiotics of 1000 times of the corresponding minimal inhibitory concentrations (1000 × MIC), and monitored spectroscopically with a microplate reader in a high-throughput manner. The hydrogels are dissolvable on demand without the need for manual scraping, thus enabling measurements of phenotypic changes. Bacteria inside the biofilm microreactors are found to survive exposure to 1000 × MIC of antibiotics, and subsequent comparison with plating results reveals no antibiotic resistance-associated phenotypes. The presented microreactor offers an attractive platform to study the tolerance and antibiotic resistance of surface-independent biofilms such as those found in tissues.
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Affiliation(s)
- Le Hoang Phu Pham
- Department of Mechanical Engineering, The Catholic University of America, Washington, DC, 20064, USA
| | - Khanh Loan Ly
- Department of Biomedical Engineering, The Catholic University of America, Washington, DC, 20064, USA
| | - Mariliz Colon-Ascanio
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Jin Ou
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Hao Wang
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, White Oak, MD, 20993, USA
| | - Sang Won Lee
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, White Oak, MD, 20993, USA
| | - Yi Wang
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, White Oak, MD, 20993, USA
| | - John S. Choy
- Department of Biology, The Catholic University of America, Washington, DC, 20064, USA
| | - Kenneth Scott Phillips
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, White Oak, MD, 20993, USA
| | - Xiaolong Luo
- Department of Mechanical Engineering, The Catholic University of America, Washington, DC, 20064, USA
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Ly KL, Hu P, Raub CB, Luo X. Programmable Physical Properties of Freestanding Chitosan Membranes Electrofabricated in Microfluidics. MEMBRANES 2023; 13:294. [PMID: 36984680 PMCID: PMC10052736 DOI: 10.3390/membranes13030294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/14/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Microfluidic-integrated freestanding membranes with suitable biocompatibility and tunable physicochemical properties are in high demand for a wide range of life science and biological studies. However, there is a lack of facile and rapid methods to integrate such versatile membranes into microfluidics. A recently invented interfacial electrofabrication of chitosan membranes offers an in-situ membrane integration strategy that is flexible, controllable, simple, and biologically friendly. In this follow-up study, we explored the ability to program the physical properties of these chitosan membranes by varying the electrofabrication conditions (e.g., applied voltage and pH of alginate). We found a strong association between membrane growth rate, properties, and fabrication parameters: high electrical stimuli and pH of alginate resulted in high optical retardance and low permeability, and vice versa. This suggests that the molecular alignment and density of electrofabricated chitosan membranes could be actively tailored according to application needs. Lastly, we demonstrated that this interfacial electrofabrication could easily be expanded to produce chitosan membrane arrays with higher uniformity than the previously well-established flow assembly method. This study demonstrates the tunability of the electrofabricated membranes' properties and functionality, thus expanding the utility of such membranes for broader applications in the future.
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Affiliation(s)
- Khanh L. Ly
- Department of Biomedical Engineering, School of Engineering, Catholic University of America, Washington, DC 20064, USA
| | - Piao Hu
- Department of Mechanical Engineering, School of Engineering, Catholic University of America, Washington, DC 20064, USA
| | - Christopher B. Raub
- Department of Biomedical Engineering, School of Engineering, Catholic University of America, Washington, DC 20064, USA
| | - Xiaolong Luo
- Department of Mechanical Engineering, School of Engineering, Catholic University of America, Washington, DC 20064, USA
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Pham LHP, Colon-Ascanio M, Ou J, Ly K, Hu P, Choy JS, Luo X. Probing mutual interactions between Pseudomonas aeruginosa and Candida albicans in a biofabricated membrane-based microfluidic platform. LAB ON A CHIP 2022; 22:4349-4358. [PMID: 36239125 PMCID: PMC9756269 DOI: 10.1039/d2lc00728b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Microbes are typically found in multi-species (polymicrobial) communities. Cooperative and competitive interactions between species, mediated by diffusible factors and physical contact, leads to highly dynamic communities that undergo changes in composition diversity and size. Infections can be more severe or more difficult to treat when caused by multiple species. Interactions between species can improve the ability of one or more species to tolerate anti-microbial treatments and host defenses. Pseudomonas aeruginosa (Pa), a ubiquitous bacterium, and the opportunistic pathogenic yeast, Candida albicans (Ca), are frequently found together in cystic fibrosis lung infections and wound infections. While significant progress has been made in determining interactions between Pa and Ca, there are still important questions that remain unanswered. Here, we probe the mutual interactions between Pa and Ca in a custom-made microfluidic device using biopolymer chitosan membranes that support cross-species communication. By assembling microbes in physically separated, chemically communicating populations or bringing into direct interactions in a mixed culture, in situ polymicrobial growth and biofilm morphology were qualitatively characterized and quantified. Our work reveals new dynamic details of their mutual interactions including cooperation, competition, invasion, and biofilm formation. The membrane-based microfluidic platform can be further developed to understand the polymicrobial interactions within a controlled interactive microenvironment to improve microbial infection prevention and treatment.
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Affiliation(s)
- Le Hoang Phu Pham
- Department of Mechanical Engineering, School of Engineering, The Catholic University of America, Washington, DC 20064, USA.
| | - Mariliz Colon-Ascanio
- Department of Biology, School of Arts and Sciences, The Catholic University of America, Washington, DC 20064, USA.
| | - Jin Ou
- Department of Biology, School of Arts and Sciences, The Catholic University of America, Washington, DC 20064, USA.
| | - Khanh Ly
- Department of Biomedical Engineering, School of Engineering, The Catholic University of America, Washington, DC 20064, USA
| | - Piao Hu
- Department of Mechanical Engineering, School of Engineering, The Catholic University of America, Washington, DC 20064, USA.
| | - John S Choy
- Department of Biology, School of Arts and Sciences, The Catholic University of America, Washington, DC 20064, USA.
| | - Xiaolong Luo
- Department of Mechanical Engineering, School of Engineering, The Catholic University of America, Washington, DC 20064, USA.
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Richter F, Bindschedler S, Calonne-Salmon M, Declerck S, Junier P, Stanley CE. Fungi-on-a-Chip: microfluidic platforms for single-cell studies on fungi. FEMS Microbiol Rev 2022; 46:6674677. [PMID: 36001464 PMCID: PMC9779915 DOI: 10.1093/femsre/fuac039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 01/07/2023] Open
Abstract
This review highlights new advances in the emerging field of 'Fungi-on-a-Chip' microfluidics for single-cell studies on fungi and discusses several future frontiers, where we envisage microfluidic technology development to be instrumental in aiding our understanding of fungal biology. Fungi, with their enormous diversity, bear essential roles both in nature and our everyday lives. They inhabit a range of ecosystems, such as soil, where they are involved in organic matter degradation and bioremediation processes. More recently, fungi have been recognized as key components of the microbiome in other eukaryotes, such as humans, where they play a fundamental role not only in human pathogenesis, but also likely as commensals. In the food sector, fungi are used either directly or as fermenting agents and are often key players in the biotechnological industry, where they are responsible for the production of both bulk chemicals and antibiotics. Although the macroscopic fruiting bodies are immediately recognizable by most observers, the structure, function, and interactions of fungi with other microbes at the microscopic scale still remain largely hidden. Herein, we shed light on new advances in the emerging field of Fungi-on-a-Chip microfluidic technologies for single-cell studies on fungi. We discuss the development and application of microfluidic tools in the fields of medicine and biotechnology, as well as in-depth biological studies having significance for ecology and general natural processes. Finally, a future perspective is provided, highlighting new frontiers in which microfluidic technology can benefit this field.
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Affiliation(s)
- Felix Richter
- Department of Bioengineering, Imperial College London, South Kensington Campus, Exhibition Road, London SW7 2AZ, United Kingdom
| | - Saskia Bindschedler
- Laboratory of Microbiology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Maryline Calonne-Salmon
- Laboratory of Mycology, Université catholique de Louvain, Place Croix du Sud 2, B-1348 Louvain-la-Neuve, Belgium
| | - Stéphane Declerck
- Laboratory of Mycology, Université catholique de Louvain, Place Croix du Sud 2, B-1348 Louvain-la-Neuve, Belgium
| | - Pilar Junier
- Laboratory of Microbiology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
| | - Claire E Stanley
- Corresponding author: Department of Bioengineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, United Kingdom. E-mail:
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Recent Progress in the Development of Droplet-based Microfluidic Technologies for Phenotypic Screening using Cell-cell Interactions. BIOTECHNOL BIOPROC E 2022. [DOI: 10.1007/s12257-022-0081-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Lam VK, Phan T, Ly K, Luo X, Nehmetallah G, Raub CB. Dual-modality digital holographic and polarization microscope to quantify phase and birefringence signals in biospecimens with a complex microstructure. BIOMEDICAL OPTICS EXPRESS 2022; 13:805-823. [PMID: 35284161 PMCID: PMC8884236 DOI: 10.1364/boe.449125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/01/2022] [Accepted: 01/05/2022] [Indexed: 05/22/2023]
Abstract
Optical phase and birefringence signals occur in cells and thin, semi-transparent biomaterials. A dual-modality quantitative phase and polarization microscope was designed to study the interaction of cells with extracellular matrix networks and to relate optical pathlength and birefringence signals within structurally anisotropic biomaterial constructs. The design was based on an existing, custom-built digital holographic microscope, to which was added a polarization microscope utilizing liquid crystal variable retarders. Phase and birefringence channels were calibrated, and data was acquired sequentially from cell-seeded collagen hydrogels and electrofabricated chitosan membranes. Computed phase height and retardance from standard targets were accurate within 99.7% and 99.8%, respectively. Phase height and retardance channel background standard deviations were 35 nm and 0.6 nm, respectively. Human fibroblasts, visible in the phase channel, aligned with collagen network microstructure, with retardance and azimuth visible in the polarization channel. Electrofabricated chitosan membranes formed in 40 µm tall microfluidic channels possessed optical retardance ranging from 7 to 11 nm, and phase height from 37 to 39 µm. These results demonstrate co-registered dual-channel acquisition of phase and birefringence parameter maps from microstructurally-complex biospecimens using a novel imaging system combining digital holographic microscopy with voltage-controlled polarization microscopy.
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Affiliation(s)
- Van K. Lam
- Department of Biomedical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
| | - Thuc Phan
- Department of Electrical Engineering and Computer Science, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
| | - Khanh Ly
- Department of Biomedical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
| | - Xiaolong Luo
- Department of Mechanical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
| | - George Nehmetallah
- Department of Electrical Engineering and Computer Science, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
| | - Christopher B. Raub
- Department of Biomedical Engineering, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
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Ly KL, Hu P, Pham LHP, Luo X. Flow-assembled chitosan membranes in microfluidics: recent advances and applications. J Mater Chem B 2021; 9:3258-3283. [PMID: 33725061 PMCID: PMC8369861 DOI: 10.1039/d1tb00045d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The integration of membranes in microfluidic devices has been extensively exploited for various chemical engineering and bioengineering applications over the past few decades. To augment the applicability of membrane-integrated microfluidic platforms for biomedical and tissue engineering studies, a biologically friendly fabrication process with naturally occurring materials is highly desired. The in situ preparation of membranes involving interfacial reactions between parallel laminar flows in microfluidic networks, known as the flow-assembly technique, is one of the most biocompatible approaches. Membranes of many types with flexible geometries have been successfully assembled inside complex microchannels using this facile and versatile flow-assembly approach. Chitosan is a naturally abundant polysaccharide known for its pronounced biocompatibility, biodegradability, good mechanical stability, ease of modification and processing, and film-forming ability under near-physiological conditions. Chitosan membranes assembled by flows in microfluidics are freestanding, robust, semipermeable, and well-aligned in microstructure, and show high affinity to bioactive reagents and biological components (e.g. biomolecules, nanoparticles, or cells) that provide facile biological functionalization of microdevices. Here, we discuss the recent developments and optimizations in the flow-assembly of chitosan membranes and chitosan-based membranes in microfluidics. Furthermore, we recapitulate the applications of the chitosan membrane-integrated microfluidic platforms dedicated to biology, biochemistry, and drug release fields, and envision the future developments of this important platform with versatile functions.
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Affiliation(s)
- Khanh L Ly
- Department of Biomedical Engineering, The Catholic University of America, Washington, DC 20064, USA
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Hu P, Raub CB, Choy JS, Luo X. Modulating the properties of flow-assembled chitosan membranes in microfluidics with glutaraldehyde crosslinking. J Mater Chem B 2020; 8:2519-2529. [DOI: 10.1039/c9tb02527h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Glutaraldehyde crosslinking significantly enhances the mechanical robustness of the originally compromised flow-assembled chitosan membranes after Pluronic passivation in microfluidics.
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Affiliation(s)
- Piao Hu
- Department of Mechanical Engineering
- The Catholic University of America
- Washington, D.C. 20064
- USA
| | - Christopher B. Raub
- Department of Biomedical Engineering
- The Catholic University of America
- Washington, D.C. 20064
- USA
| | - John S. Choy
- Department of Biology
- The Catholic University of America
- Washington, D.C. 20064
- USA
| | - Xiaolong Luo
- Department of Mechanical Engineering
- The Catholic University of America
- Washington, D.C. 20064
- USA
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