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Badiye A, Kapoor N, Shukla RK. Detection and separation of proteins using micro/nanofluidics devices. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 186:59-84. [PMID: 35033290 DOI: 10.1016/bs.pmbts.2021.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Microfluidics is the technology or system wherein the behavior of fluids' is studied onto a miniaturized device composed of chambers and tunnels. In biological and biomedical sciences, microfluidic technology/system or device serves as an ultra-high-output approach capable of detecting and separating the biomolecules present even in trace quantities. Given the essential role of protein, the identification and quantification of proteins help understand the various living systems' biological function regulation. Microfluidics has enormous potential to enable biological investigation at the cellular and molecular level and maybe a fair substitution of the sophisticated instruments/equipment used for proteomics, genomics, and metabolomics analysis. The current advancement in microfluidic systems' development is achieving momentum and opening new avenues in developing innovative and hybrid methodologies/technologies. This chapter attempts to expound the micro/nanofluidic systems/devices for their wide-ranging application to detect and separate protein. It covers microfluidic chip electrophoresis, microchip gel electrophoresis, and nanofluidic systems as protein separation systems, while methods such as spectrophotometric, mass spectrometry, electrochemical detection, magneto-resistive sensors and dynamic light scattering (DLS) are discussed as proteins' detection system.
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Affiliation(s)
- Ashish Badiye
- Department of Forensic Science, Government Institute of Forensic Sciences, Nagpur, Maharashtra, India
| | - Neeti Kapoor
- Department of Forensic Science, Government Institute of Forensic Sciences, Nagpur, Maharashtra, India
| | - Ritesh K Shukla
- Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Ahmedabad, Gujarat, India.
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2
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Giauque NA, Flowerday CE, Goates SR. Enhanced Fluorescence in a Scattering Medium. APPLIED SPECTROSCOPY 2021; 75:1461-1464. [PMID: 34269092 DOI: 10.1177/00037028211029312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Often only small amounts of sample are available for spectroscopic analytical determinations. This work investigates the enhancement of signal in columns packed with silica particles. We propose that silica particles cause the light to scatter through the column, effectively increasing optical path length. Packed columns are shown to be effective with fluorescence spectroscopy, but results were inconclusive with absorbance spectroscopy.
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Affiliation(s)
- Nathan A Giauque
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, USA
| | - Callum E Flowerday
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, USA
| | - Steven R Goates
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, USA
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3
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Estlack Z, Bennet D, Reid T, Kim J. Microengineered biomimetic ocular models for ophthalmological drug development. LAB ON A CHIP 2017; 17:1539-1551. [PMID: 28401229 DOI: 10.1039/c7lc00112f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Current ophthalmological drug discovery and testing methods have limitations and concerns regarding reliability, ethicality, and applicability. These drawbacks can be mitigated by developing biomimetic eye models through mathematical and experimental methods which are often referred to as "eye-on-a-chip" or "eye chip". These eye chip technologies emulate ocular physiology, anatomy, and microenvironmental conditions. Such models enable understanding of the fundamental biology, pharmacology, and toxicology mechanisms by investigating the pharmacokinetics and pharmacodynamics of various candidate drugs under ocular anatomical and physiological conditions without animal models. This review provides a comprehensive overview of the latest advances in theoretical and in vitro experimental models of the anterior segment of the eye and its microenvironment, including eye motions and tear film dynamics. The current state of ocular modeling and simulation from predictive models to experimental models is discussed in detail with their advantages and limitations. The potential for future eye chip models to expedite new ophthalmic drug discoveries is also discussed.
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Affiliation(s)
- Zachary Estlack
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, USA.
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4
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Roark B, Tan JA, Ivanina A, Chandler M, Castaneda J, Kim HS, Jawahar S, Viard M, Talic S, Wustholz KL, Yingling YG, Jones M, Afonin KA. Fluorescence Blinking as an Output Signal for Biosensing. ACS Sens 2016; 1:1295-1300. [PMID: 30035233 DOI: 10.1021/acssensors.6b00352] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate the first biosensing strategy that relies on quantum dot (QD) fluorescence blinking to report the presence of a target molecule. Unlike other biosensors that utilize QDs, our method does not require the analyte to induce any fluorescence intensity or color changes, making it readily applicable to a wide range of target species. Instead, our approach relies on the understanding that blinking, a single particle phenomenon, is obscured when several QDs lie within the detection volume of a confocal microscope. If QDs are engineered to aggregate when they encounter a particular target molecule, the observation of quasi-continuous emission should indicate its presence. As proof of concept, we programmed DNAs to drive rapid isothermal assembly of QDs in the presence of a target strand (oncogene K-ras). The assemblies, confirmed by various gel techniques, contained multiple QDs and were readily distinguished from free QDs by the absence of blinking.
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Affiliation(s)
- Brandon Roark
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
| | - Jenna A. Tan
- Department
of Chemistry, College of William and Mary, Williamsburg, Virginia 23185, United States
| | - Anna Ivanina
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
| | - Morgan Chandler
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
| | - Jose Castaneda
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
| | - Ho Shin Kim
- Department
of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907, United States
| | - Shriram Jawahar
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
| | - Mathias Viard
- Basic
Science Program, Leidos Biomedical
Research, Inc., RNA Biology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Strahinja Talic
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
| | - Kristin L. Wustholz
- Department
of Chemistry, College of William and Mary, Williamsburg, Virginia 23185, United States
| | - Yaroslava G. Yingling
- Department
of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7907, United States
| | - Marcus Jones
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
- Nanoscale
Science Program and The Center
for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
| | - Kirill A. Afonin
- Department
of Chemistry, University of North Carolina at Charlotte, 9201 University
City Boulevard, Charlotte, North Carolina 28223, United States
- Nanoscale
Science Program and The Center
for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, United States
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5
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Friedrich SM, Zec HC, Wang TH. Analysis of single nucleic acid molecules in micro- and nano-fluidics. LAB ON A CHIP 2016; 16:790-811. [PMID: 26818700 PMCID: PMC4767527 DOI: 10.1039/c5lc01294e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nucleic acid analysis has enhanced our understanding of biological processes and disease progression, elucidated the association of genetic variants and disease, and led to the design and implementation of new treatment strategies. These diverse applications require analysis of a variety of characteristics of nucleic acid molecules: size or length, detection or quantification of specific sequences, mapping of the general sequence structure, full sequence identification, analysis of epigenetic modifications, and observation of interactions between nucleic acids and other biomolecules. Strategies that can detect rare or transient species, characterize population distributions, and analyze small sample volumes enable the collection of richer data from biosamples. Platforms that integrate micro- and nano-fluidic operations with high sensitivity single molecule detection facilitate manipulation and detection of individual nucleic acid molecules. In this review, we will highlight important milestones and recent advances in single molecule nucleic acid analysis in micro- and nano-fluidic platforms. We focus on assessment modalities for single nucleic acid molecules and highlight the role of micro- and nano-structures and fluidic manipulation. We will also briefly discuss future directions and the current limitations and obstacles impeding even faster progress toward these goals.
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Affiliation(s)
- Sarah M Friedrich
- Biomedical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Helena C Zec
- Mechanical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Tza-Huei Wang
- Biomedical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA. and Mechanical Engineering Department, Johns Hopkins University, Baltimore, MD 21218, USA
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Wang C, Shi Y, Wang J, Pang J, Xia XH. Ultrasensitive protein concentration detection on a micro/nanofluidic enrichment chip using fluorescence quenching. ACS APPLIED MATERIALS & INTERFACES 2015; 7:6835-6841. [PMID: 25775007 DOI: 10.1021/acsami.5b00383] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A micro/nanofluidic enrichment device combined with the Förster resonance energy transfer (FRET) technique has been developed for sensitive detection of trace quantities of protein. In this approach, sample protein is first adsorbed on gold nanoparticles (AuNPs) to occupy part of the AuNP surface. Then, dye-labeled protein is added, which adsorbs to the residual active sites of the AuNP surface, saturating the AuNP surface with protein molecules. The unadsorbed dye-labeled protein remains in a free state in the system. Keeping a fixed amount of dye-labeled protein, a high concentration of sample protein leads to more free dye-labeled protein molecules remaining in the system, and thus a larger photoluminescence signal. Under the action of an electric field, the free dye-labeled protein molecules can be efficiently enriched in front of the nanochannel of a micro/nanofluidic chip, which greatly amplifies the magnitude of the photoluminescence and improves the detection sensitivity. As a demonstration, bovine serum albumin (BSA) and fluorescein isothiocyanate-labeled dog serum albumin (FITC-DSA) are used as sample and fluorescent proteins, respectively. Using the proposed strategy, a detection limit of BSA as low as 2.5 pg/mL can be achieved, which is more than 10(3) times lower than the reported minimums in most sensitive commercial protein quantification methods.
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Affiliation(s)
- Chen Wang
- †State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing 210093, China
- ‡Key Laboratory of Biomedical Functional Materials, Department of Physical Chemistry, School of Science, China Pharmaceutical University, Nanjing 211198, China
| | - Yi Shi
- †State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing 210093, China
| | - Jiong Wang
- †State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing 210093, China
| | - Jie Pang
- †State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing 210093, China
| | - Xing-Hua Xia
- †State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing 210093, China
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7
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Rane TD, Zec H, Puleo C, Lee AP, Wang TH. Droplet microfluidics for amplification-free genetic detection of single cells. LAB ON A CHIP 2012; 12:3341-7. [PMID: 22842841 PMCID: PMC3696383 DOI: 10.1039/c2lc40537g] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
In this article we present a novel droplet microfluidic chip enabling amplification-free detection of single pathogenic cells. The device streamlines multiple functionalities to carry out sample digitization, cell lysis, probe-target hybridization for subsequent fluorescent detection. A peptide nucleic acid fluorescence resonance energy transfer probe (PNA beacon) is used to detect 16S rRNA present in pathogenic cells. Initially the sensitivity and quantification abilities of the platform are tested using a synthetic target mimicking the actual expression level of 16S rRNA in single cells. The capability of the device to perform "sample-to-answer" pathogen detection of single cells is demonstrated using E. coli as a model pathogen.
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Affiliation(s)
- Tushar D. Rane
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
| | - Helena Zec
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
| | - Chris Puleo
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
| | - Abraham P. Lee
- Department of Biomedical Engineering, University of California, Irvine, Irvine, USA.; Tel: +1 949 824 9691
| | - Tza-Huei Wang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 516 7086
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8
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Zec H, Rane TD, Wang TH. Microfluidic platform for on-demand generation of spatially indexed combinatorial droplets. LAB ON A CHIP 2012; 12:3055-62. [PMID: 22810353 PMCID: PMC3657393 DOI: 10.1039/c2lc40399d] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We propose a highly versatile and programmable nanolitre droplet-based platform that accepts an unlimited number of sample plugs from a multi-well plate, performs digitization of these sample plugs into smaller daughter droplets and subsequent synchronization-free, robust injection of multiple reagents into the sample daughter droplets on-demand. This platform combines excellent control of valve-based microfluidics with the high-throughput capability of droplet microfluidics. We demonstrate the functioning of a proof-of-concept device which generates combinatorial mixture droplets from a linear array of sample plugs and four different reagents, using food dyes to mimic samples and reagents. Generation of a one dimensional array of the combinatorial mixture droplets on the device leads to automatic spatial indexing of these droplets, precluding the need to include a barcode in each droplet to identify its contents. We expect this platform to further expand the range of applications of droplet microfluidics to include applications requiring a high degree of multiplexing as well as high throughput analysis of multiple samples.
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Affiliation(s)
- Helena Zec
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
| | - Tushar D. Rane
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
| | - Tza-Huei Wang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 5164746
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, USA.; Tel: +1 410 516 7086
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9
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Vannoy CH, Tavares AJ, Noor MO, Uddayasankar U, Krull UJ. Biosensing with quantum dots: a microfluidic approach. SENSORS (BASEL, SWITZERLAND) 2011; 11:9732-63. [PMID: 22163723 PMCID: PMC3231262 DOI: 10.3390/s111009732] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 10/04/2011] [Accepted: 10/17/2011] [Indexed: 01/09/2023]
Abstract
Semiconductor quantum dots (QDs) have served as the basis for signal development in a variety of biosensing technologies and in applications using bioprobes. The use of QDs as physical platforms to develop biosensors and bioprobes has attracted considerable interest. This is largely due to the unique optical properties of QDs that make them excellent choices as donors in fluorescence resonance energy transfer (FRET) and well suited for optical multiplexing. The large majority of QD-based bioprobe and biosensing technologies that have been described operate in bulk solution environments, where selective binding events at the surface of QDs are often associated with relatively long periods to reach a steady-state signal. An alternative approach to the design of biosensor architectures may be provided by a microfluidic system (MFS). A MFS is able to integrate chemical and biological processes into a single platform and allows for manipulation of flow conditions to achieve, by sample transport and mixing, reaction rates that are not entirely diffusion controlled. Integrating assays in a MFS provides numerous additional advantages, which include the use of very small amounts of reagents and samples, possible sample processing before detection, ultra-high sensitivity, high throughput, short analysis time, and in situ monitoring. Herein, a comprehensive review is provided that addresses the key concepts and applications of QD-based microfluidic biosensors with an added emphasis on how this combination of technologies provides for innovations in bioassay designs. Examples from the literature are used to highlight the many advantages of biosensing in a MFS and illustrate the versatility that such a platform offers in the design strategy.
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Affiliation(s)
- Charles H. Vannoy
- Chemical Sensors Group, Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd. North, Mississauga, Ontario L5L 1C6, Canada; E-Mails: (C.H.V.); (A.J.T.); (M.O.N.); (U.U.)
| | | | | | | | - Ulrich J. Krull
- Chemical Sensors Group, Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Rd. North, Mississauga, Ontario L5L 1C6, Canada; E-Mails: (C.H.V.); (A.J.T.); (M.O.N.); (U.U.)
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10
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Rivet C, Lee H, Hirsch A, Hamilton S, Lu H. Microfluidics for medical diagnostics and biosensors. Chem Eng Sci 2011. [DOI: 10.1016/j.ces.2010.08.015] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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11
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Ranasinghe RT, Brown T. Ultrasensitive fluorescence-based methods for nucleic acid detection: towards amplification-free genetic analysis. Chem Commun (Camb) 2011; 47:3717-35. [DOI: 10.1039/c0cc04215c] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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12
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Varghese SS, Zhu Y, Davis TJ, Trowell SC. FRET for lab-on-a-chip devices - current trends and future prospects. LAB ON A CHIP 2010; 10:1355-64. [PMID: 20480105 DOI: 10.1039/b924271f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This review focuses on the use of Förster Resonance Energy Transfer (FRET) to monitor intra- and intermolecular reactions occurring in microfluidic reactors. Microfluidic devices have recently been used for performing highly efficient and miniaturised biological assays for the analysis of biological entities such as cells, proteins and nucleic acids. Microfluidic assays are characterised by nanolitre to femtolitre reaction volumes, which necessitates the adoption of a sensitive optical detection scheme. FRET serves as a strong 'spectroscopic ruler' for elucidating the tertiary structure of biomolecules, as the efficiency of the non-radiative energy transfer is extremely sensitive to nanoscale changes in the separation between donor and acceptor markers attached to the biomolecule of interest. In this review, we will review the implementation of various microfluidic assays which employ FRET for diverse applications in the biomedical field, along with the advantages and disadvantages of the various approaches. The future prospects for development of microfluidic devices incorporating FRET detection will be discussed.
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Affiliation(s)
- Smitha S Varghese
- CSIRO Materials Science and Engineering, PO Box 56, Highett, Melbourne, VIC 3190, Australia
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13
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Rane T, Puleo C, Liu K, Zhang Y, Lee A, Wang T. Counting single molecules in sub-nanolitre droplets. LAB ON A CHIP 2010; 10:161-4. [PMID: 20066242 PMCID: PMC3000353 DOI: 10.1039/b917503b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We demonstrate single biomolecule detection and quantification within sub-nanolitre droplets through application of Cylindrical Illumination Confocal Spectroscopy (CICS) and droplet confinement within a retractable microfluidic constriction.
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Affiliation(s)
- T.D. Rane
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576
| | - C.M. Puleo
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576
| | - K.J. Liu
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576
| | - Y. Zhang
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576
| | - A.P. Lee
- University of California, Irvine, Departments of Biomedical Engineering and Mechanical/Aerospace Engineering, ET 716F, Irvine, CA, USA Fax: 949-824-1727; Tel: 949-824-9691
| | - T.H. Wang
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576
- Corresponding Author: Johns Hopkins University, Departments of Mechanical Engineering and Biomedical Engineering, 3400 N. Charles St., Latrobe Hall Rm. 108, Baltimore, MD, USA. Fax: 410-516-4316 ; Tel: 410-516-7086 ;
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Puleo CM, McIntosh Ambrose W, Takezawa T, Elisseeff J, Wang TH. Integration and application of vitrified collagen in multilayered microfluidic devices for corneal microtissue culture. LAB ON A CHIP 2009; 9:3221-7. [PMID: 19865728 DOI: 10.1039/b908332d] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
This paper describes the fabrication and application of microfluidic devices containing collagen vitrigel (CV) used as both a functional and sacrificial cell growth substrate for the development of corneal microtissue patches. Within the device, vacuum fixation of the CV in a dehydrated state enables quick integration with standard multilayer soft lithographic techniques, while on-chip rehydration results in a gel-like collagen substrate for microfluidic cell culture. Fluidic connectivity to both the apical and basal side of the CV permits bilayered culture of epithelium and supporting stromal cell layers. In addition, microfluidic introduction of a collagenase etching media enables sacrificial degradation of the supporting CV membrane for development of barrier tissue constructs containing minimal synthetic substrate. The utility of this platform was evaluated by miniaturizing the standard transepithelial permeability (TEP) assay in order to measure the integrity of an array of corneal tissue micropatches.
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Affiliation(s)
- Christopher M Puleo
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall, Baltimore, MD, USA.
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15
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Puleo CM, Wang TH. Microfluidic means of achieving attomolar detection limits with molecular beacon probes. LAB ON A CHIP 2009; 9:1065-72. [PMID: 19350088 PMCID: PMC3000354 DOI: 10.1039/b819605b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We used inline, micro-evaporators to concentrate and transport DNA targets to a nanoliter single molecule fluorescence detection chamber for subsequent molecular beacon probe hybridization and analysis. This use of solvent removal as a unique means of target transport in a microanalytical platform led to a greater than 5000-fold concentration enhancement and detection limits that pushed below the femtomolar barrier commonly reported using confocal fluorescence detection. This simple microliter-to-nanoliter interconnect for single molecule counting analysis resolved several common limitations, including the need for excessive fluorescent probe concentrations at low target levels and inefficiencies in direct handling of highly dilute biological samples. In this report, the hundreds of bacteria-specific DNA molecules contained in approximately 25 microliters of a 50 aM sample were shuttled to a four nanoliter detection chamber through micro-evaporation. Here, the previously undetectable targets were enhanced to the pM regime and underwent probe hybridization and highly-efficient fluorescent event analysis via microfluidic recirculation through the confocal detection volume. This use of microfluidics in a single molecule detection (SMD) platform delivered unmatched sensitivity and introduced compliment technologies that may serve to bring SMD to more widespread use in replacing conventional methodologies for detecting rare target biomolecules in both research and clinical labs.
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Affiliation(s)
- Christopher M. Puleo
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall Rm. 123, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576;
| | - Tza-Huei Wang
- Johns Hopkins University, Department of Biomedical Engineering, 3400 N. Charles St., Clark Hall Rm. 123, Baltimore, MD, USA. Fax: 410-516-4771; Tel: 410-516-7576;
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