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1.
Food Chem ; 306: 125300, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31562927

RESUMO

Chlorophyll is a valuable bioactive compound, which is used as a natural food coloring agent and a photosensitizer for photodynamic therapy because of its antioxidant properties, antimutagenic ability, and near-infrared fluorescence. However, chlorophyll is unstable when it comes to retaining its antioxidant activity, when exposed to oxygen, high temperature, or light environments. To enhance the stability of chlorophyll, a polymer encapsulation method was proposed. Polycaprolactone (PCL) was employed to encapsulate the chlorophyll, and the particles size of the composites was controlled through droplet microfluidics. The composites (chlorophyll-encapsulated PCL particles) were characterized through UV-VIS spectrometry, SEM, optical microscopy, and light exposure. The particles were spherical, with diameters adjustable from 68 to 247 µm. Additionally, the chlorophyll-encapsulated PCL particles exhibited considerably prolonged chlorophyll stability. The solid microparticle is more convenient for storage and transportation, and have great potential for application in the food industry.


Assuntos
Clorofila/química , Poliésteres/química , Microfluídica/métodos , Tamanho da Partícula
2.
Food Chem ; 307: 125530, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639579

RESUMO

The Surface Plasmon resonance (SPR) based label-free detection of small targeted molecules is a great challenge and require substantial signal amplification for the accurate and precise quantification. The incorporation of noble metal nanoparticles (NPs) like gold (Au) NPs for the fabrication of SPR biosensor has shown remarkable impact both for anchoring the signal amplification and generate plasmonic resonant coupling between NPs and chip surface. In this work, we present comparative studies related to the fabrication of self-assembled monolayer (SAM) and the influence of AuNPs on Au chip for Aflatoxin B1 (AFB1) detection using SPRi apparatus. The SAM Au chip was sequentially modified by EDC-NHS crosslinkers, grafting of protein-A and finally interaction with anti-AFB1 antibodies. Similar multilayer chip surface was prepared using functionalized lipoic acid AuNPs deposited on SAM Au chips followed by in situ activation of functional groups using EDC-NHS crosslinkers, grafting of protein-A and immobilization of anti-AFB1 antibodies. This multilayer functionalized AuNPs modified Au chip was successfully utilized for AFB1 detection ranging from 0.01 to 50 nM with a limit of detection of 0.003 nM. When compared to bare self-assembled Au chip which was shown to exhibit a limit of detection of 0.19 nM and a linear detection ranging from 1 to 50 nM, the AuNPs modified Au chip was proven to clearly be a better analytical tool. Finally, validation of the proposed biosensor was evaluated by spiked wheat samples and average recoveries (93 and 90.1%) were found to be acceptable.


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais/instrumentação , Nanopartículas Metálicas/química , Microfluídica , Ressonância de Plasmônio de Superfície/instrumentação , Anticorpos , Ouro , Limite de Detecção
3.
Crit Rev Food Sci Nutr ; 60(2): 201-224, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30569743

RESUMO

Due to the significant growth of food production, the potential likelihood of food contamination is increasing. Foodborne illness caused by bacterial pathogens has considerably increased over the past decades, while at the same time, the species of harmful microorganisms also varied. Conventional bacterial culturing methods have been unable to satisfy the growing requirement for food safety inspections and food quality assurance. Therefore, rapid and simple detection methods are urgently needed. The loop-mediated isothermal amplification (LAMP) technology is a highly promising approach for the rapid and sensitive detection of pathogens, which allows nucleic acid amplification under isothermal conditions. The integration of the LAMP assay onto a microfluidic chip is highly compatible with point-of-care or resource-limited settings, as it offers the capability to perform experiments in combination with high screening efficiency. Here, we provide an overview of recent advances in LAMP-based microfluidic chip technology for detecting pathogens, based on real-time or endpoint determination mechanisms. We also discuss the promoting aspects of using the LAMP technique in a microfluidic platform, to supply a guideline for further molecular diagnosis and genetic analysis.


Assuntos
Inocuidade dos Alimentos , Doenças Transmitidas por Alimentos , Microfluídica , Contaminação de Alimentos , Humanos , Técnicas de Amplificação de Ácido Nucleico
4.
Pharm Res ; 37(1): 8, 2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31848830

RESUMO

PURPOSE: Microphysiological systems (MPS), also known as "organs-on-chips" or "tissue chips," leverage recent advances in cell biology, tissue engineering, and microfabrication to create in vitro models of human organs and tissues. These systems offer promising solutions for modeling human physiology and disease in vitro and have multiple applications in areas where traditional cell culture and animal models fall short. Recently, the National Center for Advancing Translational Sciences (NCATS) at the National Institutes of Health (NIH) and the International Space Station (ISS) U.S. National Laboratory have coordinated efforts to facilitate the launch and use of these MPS platforms onboard the ISS. Here, we provide an introduction to the NIH Tissue Chips in Space initiative and an overview of the coordinated efforts between NIH and the ISS National Laboratory. We also highlight the current progress in addressing the scientific and technical challenges encountered in the development of these ambitious projects. Finally, we describe the potential impact of the Tissue Chips in Space program for the MPS field as well as the wider biomedical and health research communities.


Assuntos
Engenharia Tecidual/métodos , Ausência de Peso , Animais , Humanos , Microfluídica , Voo Espacial , Estados Unidos
5.
Zhongguo Yi Liao Qi Xie Za Zhi ; 43(6): 422-424, 2019 Nov 30.
Artigo em Chinês | MEDLINE | ID: mdl-31854527

RESUMO

This paper introduces the technical principle of microfluidic immunofluorescence interpreters, and then introduces the development method of reader from the aspects of the system, optics, hardware and software algorithms. Firstly, the photoelectric sensor of the reader is designed, and then the software algorithms such as filtering the data scanned by the sensor and finding the curve peak are researched. Finally, the quantitative concentration result of the sample liquid is obtained. In this paper, a quantitative experimental test on clinical PSA standard samples was performed, and the results indicate the correlation coefficient between the reader and the FREND reader of NanoEnTek was more than 99%, and the CV is less than 10%.


Assuntos
Microfluídica , Algoritmos , Imunofluorescência , Software
6.
Adv Exp Med Biol ; 1174: 223-263, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31713201

RESUMO

Nanofibrillar forms of amyloidogenic proteins were initially discovered in the context of protein misfolding and disease but have more recently been found at the origin of key biological functionality in many naturally occurring functional materials, such as adhesives and biofilm coatings. Their physiological roles in nature reflect their great strength and stability, which has led to the exploration of their use as the basis of artificial protein-based functional materials. Particularly for biomedical applications, they represent attractive building blocks for the development of, for instance, drug carrier agents due to their inherent biocompatibility and biodegradability. Furthermore, the propensity of proteins to self-assemble into amyloid fibrils can be exploited under microconfinement, afforded by droplet microfluidic techniques. This approach allows the generation of multi-scale functional microgels that can host biological additives and can be designed to incorporate additional functionality, such as to aid targeted drug delivery.


Assuntos
Proteínas Amiloidogênicas , Géis , Proteínas Amiloidogênicas/química , Proteínas Amiloidogênicas/metabolismo , Tecnologia Biomédica/tendências , Géis/química , Microfluídica
7.
Adv Exp Med Biol ; 1174: 401-440, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31713207

RESUMO

The human body can be viewed as an organism consisting of a variety of cellular and non-cellular materials interacting in a highly ordered manner. Its complex and hierarchical nature inspires the multi-level recapitulation of the human body in order to gain insights into the inner workings of life. While traditional cell culture models have led to new insights into the cellular microenvironment and biological control in vivo, deeper understanding of biological systems and human pathophysiology requires the development of novel model systems that allow for analysis of complex internal and external interactions within the cellular microenvironment in a more relevant organ context. Engineering organ-on-chip systems offers an unprecedented opportunity to unravel the complex and hierarchical nature of human organs. In this chapter, we first highlight the advances in microfluidic platforms that enable engineering of the cellular microenvironment and the transition from cells-on-chips to organs-on-chips. Then, we introduce the key features of the emerging organs-on-chips and their proof-of-concept applications in biomedical research. We also discuss the challenges and future outlooks of this state-of-the-art technology.


Assuntos
Microfluídica , Engenharia Tecidual , Microambiente Celular , Humanos , Microfluídica/tendências , Modelos Biológicos , Técnicas de Cultura de Órgãos/tendências , Fisiologia/tendências , Engenharia Tecidual/tendências
8.
Pharm Res ; 36(12): 183, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31741058

RESUMO

Research conducted in microgravity conditions has the potential to yield new therapeutics, as advances can be achieved in the absence of phenomena such as sedimentation, hydrostatic pressure and thermally-induced convection. The outcomes of such studies can significantly contribute to many scientific and technological fields, including drug discovery. This article reviews the existing traditional microgravity platforms as well as emerging ideas for enabling microgravity research focusing on SpacePharma's innovative autonomous remote-controlled microgravity labs that can be launched to space aboard nanosatellites to perform drug research in orbit. The scientific literature is reviewed and examples of life science fields that have benefited from studies in microgravity conditions are given. These include the use of microgravity environment for chemical applications (protein crystallization, drug polymorphism, self-assembly of biomolecules), pharmaceutical studies (microencapsulation, drug delivery systems, behavior and stability of colloidal formulations, antibiotic drug resistance), and biological research, including accelerated models for aging, investigation of bacterial virulence , tissue engineering using organ-on-chips in space, enhanced stem cells proliferation and differentiation.


Assuntos
Simulação de Ausência de Peso/instrumentação , Simulação de Ausência de Peso/métodos , Ausência de Peso , Fatores Etários , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Cristalização/instrumentação , Cristalização/métodos , Dimerização , Composição de Medicamentos/instrumentação , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Descoberta de Drogas/instrumentação , Descoberta de Drogas/métodos , Resistência Microbiana a Medicamentos , Humanos , Microfluídica/instrumentação , Microfluídica/métodos , Pesquisa Farmacêutica/instrumentação , Pesquisa Farmacêutica/métodos , Fenômenos Físicos , Proteínas/química , Voo Espacial , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
9.
Soft Matter ; 15(46): 9565-9578, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31724682

RESUMO

The performance of orally administered lipid-based drug formulations is crucially dependent on digestion, and understanding the colloidal structures formed during digestion is necessary for rational formulation design. Previous studies using the established bulk pH-stat approach (Hong et al. 2015), coupled to synchrotron small angle X-ray scattering (SAXS), have begun to shed light on this subject. Such studies of digestion using in situ SAXS measurements are complex and have limitations regarding the resolution of intermediate structures. Using a microfluidic device, the digestion of lipid systems may be monitored with far better control over the mixing of the components and the application of enzyme, thereby elucidating a finer understanding of the structural progression of these lipid systems. This work compares a simple T-junction microcapillary device and a custom-built microfluidic chip featuring hydrodynamic flow focusing, with an equivalent experiment with the full scale pH-stat approach. Both microfluidic devices were found to be suitable for in situ SAXS measurements in tracking the kinetics with improved time and signal sensitivity compared to other microfluidic devices studying similar lipid-based systems, and producing more consistent and controllable structural transformations. Particle sizing of the nanoparticles produced in the microfluidic devices were more consistent than the pH-stat approach.


Assuntos
Lipase/metabolismo , Lipídeos/química , Lipossomos/química , Microfluídica/métodos , Nanopartículas/química , Difração de Raios X/métodos , Composição de Medicamentos/métodos , Microfluídica/instrumentação , Espalhamento a Baixo Ângulo , Difração de Raios X/instrumentação
10.
Adv Exp Med Biol ; 1146: 79-103, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31612455

RESUMO

The last 20 years have seen the blooming of microfluidics technologies applied to biological sciences. Microfluidics provides effective tools for biological analysis, allowing the experimentalists to extend their playground to single cells and single molecules, with high throughput and resolution which were inconceivable few decades ago. In particular, microfluidic devices are profoundly changing the conventional way of studying the cell motility and cell migratory dynamics. In this chapter we will furnish a comprehensive view of the advancements made in the research domain of confinement-induced cell migration, thanks to the use of microfluidic devices. The chapter is subdivided in three parts. Each section will be addressing one of the fundamental questions that the microfluidic technology is contributing to unravel: (i) where cell migration takes place, (ii) why cells migrate and, (iii) how the cells migrate. The first introductory part is devoted to a thumbnail, and partially historical, description of microfluidics and its impact in biological sciences. Stress will be put on two aspects of the devices fabrication process, which are crucial for biological applications: materials used and coating methods. The second paragraph concerns the cell migration induced by environmental cues: chemical, leading to chemotaxis, mechanical, at the basis of mechanotaxis, and electrical, which induces electrotaxis. Each of them will be addressed separately, highlighting the fundamental role of microfluidics in providing the well-controlled experimental conditions where cell migration can be induced, investigated and ultimately understood. The third part of the chapter is entirely dedicated to how the cells move in confined environments. Invadosomes (the joint name for podosomes and invadopodia) are cell protrusion that contribute actively to cell migration or invasion. The formation of invadosomes under confinement is a research topic that only recently has caught the attention of the scientific community: microfluidic design is helping shaping the future direction of this emerging field of research.


Assuntos
Movimento Celular , Microfluídica , Podossomos , Animais , Quimiotaxia , Humanos , Dispositivos Lab-On-A-Chip , Microfluídica/instrumentação , Podossomos/metabolismo , Pesquisa/tendências
11.
Chem Commun (Camb) ; 55(87): 13112-13115, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31612874

RESUMO

Biocompatible chemical cross-linked hybrid polyethylene glycol-based hydrogels were obtained from a sol-gel process using bis-silylated molecular precursors in biocompatible conditions. This soft procedure (pH = 7.4, at 25 °C), allows the production of microgels by microfluidics and easy encapsulation of a model protein (Bovin Serum Albumine, BSA).


Assuntos
Materiais Biocompatíveis/síntese química , Hidrogéis/síntese química , Microfluídica , Polietilenoglicóis/síntese química , Soroalbumina Bovina/química , Animais , Materiais Biocompatíveis/química , Bovinos , Géis/química , Hidrogéis/química , Estrutura Molecular , Tamanho da Partícula , Polietilenoglicóis/química , Propriedades de Superfície
12.
Se Pu ; 37(9): 925-931, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642295

RESUMO

Reproduction is one of the most basic characteristics of organisms, and the guarantee of the continuation and evolution of a species. As the country with world's largest population, China has been gradually increasing its investment in research on the reproductive system in recent years, particularly in the field of basic research. The rapid development and wide application of the microfluidic technology since its birth are sufficient to explain its application prospect. Currently, infertility and birth defects are major problems in the field of reproduction. Micro-reproductive technologies, including microfluidic and organs-on-chips, are formed through the combination of a wide range of basic science and bioengineering technologies. In reproductive research, microfluidic technology display several advantages:flexible design of the microchannel shape and size to better simulate the physiological environment, the low consumption of microfluidic chip, and highly integrated microfluidic technology. Microfluidic technology has been applied to various processes including sperm vitality evaluation and screening, sperm chemotaxis, cumulus oophorus cell removal, zona pellucida removal, ootid localization and screening, fertilization, early embryo culture and reproductive organ simulation. This paper introduces the recent progress in reproductive research based on microfluidic technology and its application prospects.


Assuntos
Microfluídica/tendências , Reprodução , Técnicas Reprodutivas/tendências , Humanos
13.
Adv Exp Med Biol ; 1186: 171-193, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31654390

RESUMO

The success rate from investigational new drug filing to drug approval has remained low for decades despite major scientific and technological advances, and a steady increase of funding and investment. The failure to demonstrate drug efficacy has been the major reason that drug development does not progress beyond phase II and III clinical trials. The combination of two-dimensional (2D) cellular in vitro and animal models has been the gold standard for basic science research and preclinical drug development studies. However, most findings from these systems fail to translate into human trials because these models only partly recapitulate human physiology and pathology. The lack of a dynamic three-dimensional microenvironment in 2D cellular models reduces the physiological relevance, and for these reasons, 3D and microfluidic model systems are now being developed as more native-like biological assay platforms. 3D cellular in vitro systems, microfluidics, self-organized organoids, and 3D biofabrication are the most promising technologies to mimic human physiology because they provide mechanical cues and a 3D microenvironment to the multicellular components. With the advent of human-induced pluripotent stem cell (iPSC) technology, the 3D dynamic in vitro systems further enable extensive access to human-like tissue models. As increasingly complex 3D cellular systems are produced, the use of current visualization technologies is limited due to the thickness and opaqueness of 3D tissues. Tissue-clearing techniques improve light penetration deep into tissues by matching refractive indices among the 3D components. 3D segmentation enables quantitative measurements based on 3D tissue images. Using these state-of-the-art technologies, high-throughput screening (HTS) of thousands of drug compounds in 3D tissue models is slowly becoming a reality. In order to screen thousands of compounds, machine learning will need to be applied to help maximize outcomes from the use of cheminformatics and phenotypic approaches to drug screening. In this chapter, we discuss the current 3D ocular models recapitulating physiology and pathology of the back of the eye and further discuss visualization and quantification techniques that can be implemented for drug screening in ocular diseases.


Assuntos
Avaliação Pré-Clínica de Medicamentos , Oftalmopatias , Modelos Biológicos , Organoides , Engenharia Tecidual , Animais , Avaliação Pré-Clínica de Medicamentos/métodos , Oftalmopatias/patologia , Oftalmopatias/terapia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Microfluídica
14.
EMBO J ; 38(22): e101876, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31583725

RESUMO

Clonal microbial populations are inherently heterogeneous, and this diversification is often considered as an adaptation strategy. In clinical infections, phenotypic diversity is found to be associated with drug tolerance, which in turn could evolve into genetic resistance. Mycobacterium tuberculosis, which ranks among the top ten causes of mortality with high incidence of drug-resistant infections, exhibits considerable phenotypic diversity. In this study, we quantitatively analyze the cellular dynamics of DNA damage responses in mycobacteria using microfluidics and live-cell fluorescence imaging. We show that individual cells growing under optimal conditions experience sporadic DNA-damaging events manifested by RecA expression pulses. Single-cell responses to these events occur as transient pulses of fluorescence expression, which are dependent on the gene-network structure but are triggered by extrinsic signals. We demonstrate that preexisting subpopulations, with discrete levels of DNA damage response, are associated with differential susceptibility to fluoroquinolones. Our findings reveal that the extent of DNA integrity prior to drug exposure impacts the drug activity against mycobacteria, with conceivable therapeutic implications.


Assuntos
Proteínas de Bactérias/metabolismo , Ciprofloxacino/farmacologia , Dano ao DNA/genética , Mycobacterium tuberculosis/genética , Análise de Célula Única , Estresse Fisiológico , Tuberculose/patologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Dano ao DNA/efeitos dos fármacos , Humanos , Microfluídica , Mycobacterium tuberculosis/efeitos dos fármacos , Recombinases Rec A/genética , Recombinases Rec A/metabolismo , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia
16.
Nature ; 574(7777): 228-232, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31597972

RESUMO

Microfluidic systems can deliver portable point-of-care diagnostics without the need for external equipment or specialist operators, by integrating all reagents and manipulations required for a particular assay in one device1. A key approach is to deposit picogram quantities of dried reagents in microchannels with micrometre precision using specialized inkjet plotters2-5. This means that reagents can be stored for long periods of time and reconstituted spontaneously when adding a liquid sample. But it is challenging to carry out complex operations using multiple reagents, because shear flow enhances their dispersion and they tend to accumulate at moving liquid fronts, resulting in poor spatiotemporal control over the concentration profile of the reconstituted reagents6. One solution is to limit the rate of release of reagents into the liquid7-10. However, this requires the fine-tuning of different reagents, conditions and targeted operations, and cannot readily produce the complex, time-dependent multireagent concentration pulses required for sophisticated on-chip assays. Here we report and characterize a capillary flow phenomenon that we term self-coalescence, which is seen when a confined liquid with a stretched air-liquid interface is forced to 'zip' back onto itself in a microfluidic channel, thereby allowing reagent reconstitution with minimal dispersion. We provide a comprehensive framework that captures the physical underpinning of this effect. We also fabricate scalable, compact and passive microfluidic structures-'self-coalescence modules', or SCMs-that exploit and control this phenomenon in order to dissolve dried reagent deposits in aqueous solutions with precise spatiotemporal control. We show that SCMs can reconstitute multiple reagents so that they either undergo local reactions or are sequentially delivered in a flow of liquid. SCMs are easily fabricated in different materials, readily configured to enable different reagent manipulations, and readily combined with other microfluidic technologies, so should prove useful for assays, diagnostics, high-throughput screening and other technologies requiring efficient preparation and manipulation of small volumes of complex solutions.


Assuntos
Indicadores e Reagentes/análise , Microfluídica/métodos , Técnicas de Química Analítica/instrumentação , Técnicas de Química Analítica/métodos , Testes Diagnósticos de Rotina , Ensaios Enzimáticos/instrumentação , Ensaios Enzimáticos/métodos , Fluorometria , Glucosefosfato Desidrogenase/análise , Glucosefosfato Desidrogenase/metabolismo , Papillomavirus Humano 16/genética , Papillomavirus Humano 16/isolamento & purificação , Papillomavirus Humano 18/genética , Papillomavirus Humano 18/isolamento & purificação , Humanos , Microfluídica/instrumentação , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Técnicas de Amplificação de Ácido Nucleico/métodos
17.
Molecules ; 24(18)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31547232

RESUMO

Use of sonication for designing and fabricating reactors, especially the deposition of catalysts inside a microreactor, is a modern approach. There are many reports that prove that a microreactor is a better setup compared with batch reactors for carrying out catalytic reactions. Microreactors have better energy efficiency, reaction rate, safety, a much finer degree of process control, better molecular diffusion, and heat-transfer properties compared with the conventional batch reactor. The use of microreactors for photocatalytic reactions is also being considered to be the appropriate reactor configuration because of its improved irradiation profile, better light penetration through the entire reactor depth, and higher spatial illumination homogeneity. Ultrasound has been used efficiently for the synthesis of materials, degradation of organic compounds, and fuel production, among other applications. The recent increase in energy demands, as well as the stringent environmental stress due to pollution, have resulted in the need to develop green chemistry-based processes to generate and remove contaminants in a more environmentally friendly and cost-effective manner. It is possible to carry out the synthesis and deposition of catalysts inside the reactor using the ultrasound-promoted method in the microfluidic system. In addition, the synergistic effect generated by photocatalysis and sonochemistry in a microreactor can be used for the production of different chemicals, which have high value in the pharmaceutical and chemical industries. The current review highlights the use of both photocatalysis and sonochemistry for developing microreactors and their applications.


Assuntos
Fotoquímica/instrumentação , Sonicação/métodos , Catálise , Desenho de Equipamento , Microfluídica/instrumentação , Nanopartículas/química , Fotoquímica/métodos , Ultrassom/instrumentação , Ultrassom/métodos
18.
Environ Sci Technol ; 53(20): 11755-11763, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31532190

RESUMO

Phages (i.e., viruses that infect bacteria) have been considered as good tracers for the hydrological transport of colloids and (pathogenic) viruses. However, little is known about interactions of phages with (fungal) mycelia as the prevalent soil microbial biomass. Forming extensive and dense networks, mycelia provide significant surfaces for phage-hyphal interactions. Here, for the first time, we quantified the mycelial retention of phages in a microfluidic platform that allowed for defined fluid exchange around hyphae. Two common lytic tracer phages (Escherichia coli phage T4 and marine phage PSA-HS2) and two mycelia of differing surface properties (Coprinopsis cinerea and Pythium ultimum) were employed. Phage-hyphal interaction energies were approximated by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) approach of colloidal interaction. Our data show initial hyphal retention of phages of up to ≈4 × 107 plaque-forming unit (PFU) mm-2 (≈2550 PFU mm-2 s-1) with a retention efficiency depending on the hyphal and, to a lesser extent, the phage surface properties. Experimental data were supported by XDLVO calculations, which revealed the highest attractive forces for the interaction between hydrophobic T4 phages and hydrophobic C. cinerea surfaces. Our data suggest that mycelia may be relevant for the retention of phages in the subsurface and need to be considered in subsurface phage tracer studies. Mycelia-phage interactions may further be exploited for the development of novel strategies to reduce or hinder the transport of undesirable (bio) colloidal entities in environmental filter systems.


Assuntos
Bacteriófagos , Coloides , Microfluídica , Micélio , Propriedades de Superfície
20.
Mater Sci Eng C Mater Biol Appl ; 104: 109705, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499950

RESUMO

Microfluidics-based microfibers have been widely used as bottom-up scaffolds for tissue engineering applications. Different forms of microfibers with certain thickness of shell have been developed during the past decade. Ultra-thin microfiber, as a special and promising carrier of cells, was less explored. In this work, by using the interfacial ionic interaction between sodium alginate (NaA) and chitosan (CS), a novel ultra-thin polyelectrolyte hollow microfiber with the diameter of ~200 µm and the shell thickness of 1.3 ±â€¯0.3 µm was fabricated via a microfluidic device for liver tissue engineering. The fluorescence of FITC labeled CS confirmed the inner CS layer of the fabricated microfiber and the SEM results illustrated its ultra-thin characteristic. Although there are only two layers in the ultra-thin polyelectrolyte hollow microfiber, the following cells encapsulation experiments indicated that it could bear cells loading and the hollow space of the microfibers could encapsulate sufficient number of cells for tissue engineering applications. The presence of inner CS layer in the microfiber promoted cell adhesion and ultra-thin shell characteristic facilitated the exchange of nutrient substance and O2 and thus promoted cell proliferation. HepG2 cells encapsulated in the microfibers maintained favorable viability, proliferation ability and hepatic specific functions during 10 days' culture. These results suggest that the established polyelectrolyte microfibers hold great potential applications in the field of liver tissue engineering. We believe this work will lead to the development of innovative methodologies and materials for both cell culture and biomedical application.


Assuntos
Microfluídica/métodos , Polieletrólitos/química , Alginatos/química , Células Imobilizadas/citologia , Quitosana/química , Fluorescência , Células Hep G2 , Humanos , Reologia , Soluções
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