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Wei TY, Fu Y, Chang KH, Lin KJ, Lu YJ, Cheng CM. Point-of-Care Devices Using Disease Biomarkers To Diagnose Neurodegenerative Disorders. Trends Biotechnol 2017; 36:290-303. [PMID: 29242004 DOI: 10.1016/j.tibtech.2017.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 12/16/2022]
Abstract
Neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases are highly prevalent and immensely destructive to the health and well-being of individuals and their families across the globe. Neurodegenerative diseases are characterized by the gradual loss of neural tissue in the central nervous system. Clearly, early diagnosis of the onset of neurodegeneration is vital and beneficial. Current diagnostic methods rely heavily on symptoms or autopsy results, thus overlooking early diagnosis, the only opportunity for amelioration. However, appropriately selected and used biomarker diagnostics provide a solution. This article reviews the development and application of biomarker-related diagnostics for neurodegenerative disease with specific recommendations for point-of-care (POC) methodology. These advantageous approaches may offer a solution to existing obstacles and limitations to neurodegenerative disease treatment.
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Affiliation(s)
- Ting-Yen Wei
- Interdisciplinary Program of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan; These authors contributed equally
| | - Yun Fu
- Department of Dermatology, Chang Gung Memorial Hospital Linkou Medical Center, Taoyuan 33305, Taiwan; These authors contributed equally
| | - Kuo-Hsuan Chang
- Department of Neurology, Chang Gung Memorial Hospital Linkou Medical Center and College of Medicine, Chang Gung University, Taoyuan 33305, Taiwan
| | - Kun-Ju Lin
- Animal Molecular Imaging Center and Department of Nuclear Medicine, Chang Gung Memorial Hospital Linkou Medical Center, Taoyuan 33305, Taiwan
| | - Yu-Jen Lu
- Department of Neurosurgery, Chang Gung Memorial Hospital Linkou Medical Center and College of Medicine, Chang Gung University, Taoyuan 33305, Taiwan.
| | - Chao-Min Cheng
- Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
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2
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Development of a novel magnetophoresis-assisted hydrophoresis microdevice for rapid particle ordering. Biomed Microdevices 2017; 18:54. [PMID: 27289469 DOI: 10.1007/s10544-016-0078-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Focusing and ordering of micro- or nanoparticles is an essential ability in microfluidic platforms for bio-sample processing. Hydrophoresis is an effective method utilising hydrodynamic force to focus microparticles, but it is limited by the fixed operational range and the lack of flexibility. Here, we report a work to tune and improve the dynamic range of hydrophoresis device using magnetophoresis. In this work, a novel approach was presented to fabricate the lateral fluidic ports, which allow the flipped chip to remain stable on the stage of microscope. Diamagnetic polystyrene microparticles suspended in a ferrofluidic medium were repelled to the lower level of the channel by negative magnetophoretic force, and then interact with grooves of microchannel to obtain an excellent hydrophoretic ordering. The effects of (i) flow rate, (ii) particle size, (iii) magnetic susceptibility of the medium, and (iv) number of magnets on the particle focusing efficiency were also reported. As the proposed magnetophorsis-assisted hydrophoretic device is tuneable and simple, it holds great potential to be integrated with other microfluidic components to form an integrated sample-to-answer system.
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Ohwada H, Nakayama T, Kanaya Y, Tanaka Y. Serum albumin levels and their correlates among individuals with motor disorders at five institutions in Japan. Nutr Res Pract 2017; 11:57-63. [PMID: 28194266 PMCID: PMC5300948 DOI: 10.4162/nrp.2017.11.1.57] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 11/18/2016] [Accepted: 12/09/2016] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND/OBJECTIVES The level of serum albumin is an index of nourishment care and management. However, the distribution and correlates of serum albumin levels among individuals with motor disorders have not been reported until now. Therefore, we examined the distribution and correlates of serum albumin levels among individuals with motor disorders. SUBJECTS/METHODS A cross-sectional study on 249 individuals with motor disabilities (144 men, mean age: 51.4 years; 105 women, mean age: 51.4 years) was conducted at five institutions in Ibaraki Prefecture, Japan in 2008. The results were compared with data from the National Health and Nutrition Survey. RESULTS The mean serum albumin levels were 4.0 ± 0.4 g/dL for men and 3.8 ± 0.5 g/dL for women. Overall, 17 (11.8%) men and 25 (23.8%) women had hypoalbuminemia (serum albumin level ≤ 3.5 g/dL); these proportions were greater than those among healthy Japanese adults (≤ 1%). Low serum albumin level was related with female sex, older age, low calf circumference, low relative daily energy intake, low hemoglobin (Hb), low blood platelet count, low high-density lipoprotein cholesterol (HDL-C), low HbA1c, and high C-reactive protein (CRP) levels. The strongest correlates, based on standardized betas, were Hb (0.321), CRP (-0.279), and HDL-C (0.279) levels. CONCLUSIONS These results indicate that the prevalence of hypoalbuminemia is higher in individuals with motor disabilities than in healthy individuals and that inflammation is a strong negative correlate of serum albumin levels. Therefore, inflammation should be examined for the assessment of hypoalbuminemia among institutionalized individuals with motor disabilities.
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Affiliation(s)
- Hiroko Ohwada
- Department of Health and Nutrition, Yamagata Prefectural Yonezawa University of Nutrition Sciences, 6-15-1 Torimachi, Yonezawa, Yamagata 992-0025, Japan
| | - Takeo Nakayama
- Department of Health Informatics, Kyoto University School of Public Health, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Kanaya
- Department of Health and Nutrition, Yamagata Prefectural Yonezawa University of Nutrition Sciences, 6-15-1 Torimachi, Yonezawa, Yamagata 992-0025, Japan
| | - Yuki Tanaka
- Department of Health and Nutrition, Yamagata Prefectural Yonezawa University of Nutrition Sciences, 6-15-1 Torimachi, Yonezawa, Yamagata 992-0025, Japan
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Spindel S, Sapsford KE. Evaluation of optical detection platforms for multiplexed detection of proteins and the need for point-of-care biosensors for clinical use. SENSORS (BASEL, SWITZERLAND) 2014; 14:22313-41. [PMID: 25429414 PMCID: PMC4299016 DOI: 10.3390/s141222313] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 11/16/2022]
Abstract
This review investigates optical sensor platforms for protein multiplexing, the ability to analyze multiple analytes simultaneously. Multiplexing is becoming increasingly important for clinical needs because disease and therapeutic response often involve the interplay between a variety of complex biological networks encompassing multiple, rather than single, proteins. Multiplexing is generally achieved through one of two routes, either through spatial separation on a surface (different wells or spots) or with the use of unique identifiers/labels (such as spectral separation-different colored dyes, or unique beads-size or color). The strengths and weaknesses of conventional platforms such as immunoassays and new platforms involving protein arrays and lab-on-a-chip technology, including commercially-available devices, are discussed. Three major public health concerns are identified whereby detecting medically-relevant markers using Point-of-Care (POC) multiplex assays could potentially allow for a more efficient diagnosis and treatment of diseases.
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Affiliation(s)
- Samantha Spindel
- Division of Biology, Chemistry, and Materials Science Office of Science and Engineering Laboratories; U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA.
| | - Kim E Sapsford
- Division of Biology, Chemistry, and Materials Science Office of Science and Engineering Laboratories; U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA.
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Jiang H, Weng X, Li D. A novel microfluidic flow focusing method. BIOMICROFLUIDICS 2014; 8:054120. [PMID: 25538810 PMCID: PMC4241768 DOI: 10.1063/1.4899807] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/14/2014] [Indexed: 06/04/2023]
Abstract
A new microfluidic method that allows hydrodynamic focusing in a microchannel with two sheath flows is demonstrated. The microchannel network consists of a T-shaped main channel and two T-shaped branch channels. The flows of the sample stream and the sheath streams in the microchannel are generated by electroosmotic flow-induced pressure gradients. In comparison with other flow focusing methods, this novel method does not expose the sample to electrical field, and does not need any external pumps, tubing, and valves.
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Affiliation(s)
- Hai Jiang
- Department of Mechanical and Mechatronics Engineering, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Xuan Weng
- Department of Mechanical and Mechatronics Engineering, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Dongqing Li
- Department of Mechanical and Mechatronics Engineering, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
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Spencer D, Elliott G, Morgan H. A sheath-less combined optical and impedance micro-cytometer. LAB ON A CHIP 2014; 14:3064-73. [PMID: 24964908 DOI: 10.1039/c4lc00224e] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We describe a sheath-less micro-cytometer that measures four different parameters, namely fluorescence, large angle side scatter and dual frequency electrical impedance (electrical volume and opacity). The cytometer was benchmarked using both size and fluorescent bead standards and demonstrates excellent size accuracy (CVs ≤ 2.1%), sensitivity and dynamic range (3.5 orders of magnitude) at sample flow rates of 80 μL per minute. The cytometer was evaluated by analysing human blood, and a four part differential leukocyte assay for accurate CD4+ T-cell enumeration was demonstrated. The integration of impedance, fluorescence and side scatter into a single miniature cytometer platform provides the core information content of a classical cytometer in a highly compact, simple, portable and low cost format.
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Affiliation(s)
- Daniel Spencer
- Faculty of Physical Sciences and Engineering, and Institute for Life Sciences, University of Southampton, Southampton, Hampshire SO17 1BJ, UK.
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Boyd DA, Adams AA, Daniele MA, Ligler FS. Microfluidic fabrication of polymeric and biohybrid fibers with predesigned size and shape. J Vis Exp 2014:e50958. [PMID: 24430733 PMCID: PMC4089404 DOI: 10.3791/50958] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
A “sheath” fluid passing through a microfluidic channel at low Reynolds number can be directed around another “core” stream and used to dictate the shape as well as the diameter of a core stream. Grooves in the top and bottom of a microfluidic channel were designed to direct the sheath fluid and shape the core fluid. By matching the viscosity and hydrophilicity of the sheath and core fluids, the interfacial effects are minimized and complex fluid shapes can be formed. Controlling the relative flow rates of the sheath and core fluids determines the cross-sectional area of the core fluid. Fibers have been produced with sizes ranging from 300 nm to ~1 mm, and fiber cross-sections can be round, flat, square, or complex as in the case with double anchor fibers. Polymerization of the core fluid downstream from the shaping region solidifies the fibers. Photoinitiated click chemistries are well suited for rapid polymerization of the core fluid by irradiation with ultraviolet light. Fibers with a wide variety of shapes have been produced from a list of polymers including liquid crystals, poly(methylmethacrylate), thiol-ene and thiol-yne resins, polyethylene glycol, and hydrogel derivatives. Minimal shear during the shaping process and mild polymerization conditions also makes the fabrication process well suited for encapsulation of cells and other biological components.
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Affiliation(s)
- Darryl A Boyd
- Center for Bio/Molecular Science & Engineering, US Naval Research Laboratory
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Fan YJ, Wu YC, Chen Y, Kung YC, Wu TH, Huang KW, Sheen HJ, Chiou PY. Three dimensional microfluidics with embedded microball lenses for parallel and high throughput multicolor fluorescence detection. BIOMICROFLUIDICS 2013; 7:44121. [PMID: 24404054 PMCID: PMC3765297 DOI: 10.1063/1.4818944] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/07/2013] [Indexed: 05/11/2023]
Abstract
We report a 3D microfluidic device with 32 detection channels and 64 sheath flow channels and embedded microball lens array for high throughput multicolor fluorescence detection. A throughput of 358 400 cells/s has been accomplished. This device is realized by utilizing solid immersion micro ball lens arrays for high sensitivity and parallel fluorescence detection. High refractive index micro ball lenses (n = 2.1) are embedded underneath PDMS channels close to cell detection zones in channels. This design permits patterning high N.A. micro ball lenses in a compact fashion for parallel fluorescence detection on a small footprint device. This device also utilizes 3D microfluidic fabrication to address fluid routing issues in two-dimensional parallel sheath focusing and allows simultaneous pumping of 32 sample channels and 64 sheath flow channels with only two inlets.
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Affiliation(s)
- Y J Fan
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA ; Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan
| | - Y C Wu
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Y Chen
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA
| | - Y C Kung
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA
| | - T H Wu
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA ; Department of Pathology and Laboratory Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
| | - K W Huang
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA
| | - H J Sheen
- Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan
| | - P Y Chiou
- Mechanical and Aerospace Engineering Department, University of California Los Angeles, Los Angeles, California 90095, USA ; Department of Bioengineering, University of California Los Angeles, Los Angeles, California 90095, USA
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Martini J, Recht MI, Huck M, Bern MW, Johnson NM, Kiesel P. Time encoded multicolor fluorescence detection in a microfluidic flow cytometer. LAB ON A CHIP 2012; 12:5057-62. [PMID: 23044636 PMCID: PMC3485422 DOI: 10.1039/c2lc40515f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We describe an optical detection technique that delivers high signal-to-noise discrimination to enable a multi-parameter flow cytometer that combines high performance, robustness, compactness and low cost. The enabling technique is termed "spatially modulated detection" and generates a time-dependent signal as a continuously fluorescing (bio-) particle traverses an optical transmission pattern along the fluidic channel. Correlating the detected signal with the expected transmission pattern achieves high discrimination of the particle signal from background noise. Additionally, the particle speed and its fluorescence emission characteristics are deduced from the correlation analysis. Our method uses a large excitation/emission volume along the fluidic channel in order to increase the total flux of fluorescence light that originates from a particle while requiring minimal optical alignment. Despite the large excitation/detection volume, the mask pattern enables a high spatial resolution in the micron range. This allows for detection and characterization of particles with a separation (in flow direction) comparable to the dimension of individual particles. In addition, the concept is intrinsically tolerant of non-encoded background fluorescence originating from fluorescent components in solution, fluorescing components of the chamber and contaminants on its surface. The optical detection technique is illustrated with experimental results of multicolor detection with a single large area detector by filtering fluorescence emission of different particles through a patterned color mask. Thereby the particles' fluorescence emission spectrum is encoded in a time dependent intensity signal and color information can be extracted from the correlation analysis. The multicolor detection technique is demonstrated by differentiation of micro-beads loaded with PE (Phycoerythrin) and PE-Cy5 that are excited at 532 nm.
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Affiliation(s)
- Joerg Martini
- Palo Alto Research Center, 3333 Coyote Hill Rd., Palo Alto, CA 94304, USA.
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10
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Adiguzel Y, Kulah H. CMOS cell sensors for point-of-care diagnostics. SENSORS (BASEL, SWITZERLAND) 2012; 12:10042-66. [PMID: 23112587 PMCID: PMC3472815 DOI: 10.3390/s120810042] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/06/2012] [Accepted: 07/21/2012] [Indexed: 12/12/2022]
Abstract
The burden of health-care related services in a global era with continuously increasing population and inefficient dissipation of the resources requires effective solutions. From this perspective, point-of-care diagnostics is a demanded field in clinics. It is also necessary both for prompt diagnosis and for providing health services evenly throughout the population, including the rural districts. The requirements can only be fulfilled by technologies whose productivity has already been proven, such as complementary metal-oxide-semiconductors (CMOS). CMOS-based products can enable clinical tests in a fast, simple, safe, and reliable manner, with improved sensitivities. Portability due to diminished sensor dimensions and compactness of the test set-ups, along with low sample and power consumption, is another vital feature. CMOS-based sensors for cell studies have the potential to become essential counterparts of point-of-care diagnostics technologies. Hence, this review attempts to inform on the sensors fabricated with CMOS technology for point-of-care diagnostic studies, with a focus on CMOS image sensors and capacitance sensors for cell studies.
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Affiliation(s)
- Yekbun Adiguzel
- METU-MEMS Research and Application Center, Middle East Technical University, Ankara 06800, Turkey
| | - Haluk Kulah
- METU-MEMS Research and Application Center, Middle East Technical University, Ankara 06800, Turkey
- Department of Electrical and Electronics Engineering, Middle East Technical University, Ankara 06800, Turkey; E-Mail:
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11
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Roda A, Mirasoli M, Roda B, Bonvicini F, Colliva C, Reschiglian P. Recent developments in rapid multiplexed bioanalytical methods for foodborne pathogenic bacteria detection. Mikrochim Acta 2012. [DOI: 10.1007/s00604-012-0824-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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12
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Verbarg J, Kamgar-Parsi K, Shields AR, Howell PB, Ligler FS. Spinning magnetic trap for automated microfluidic assay systems. LAB ON A CHIP 2012; 12:1793-9. [PMID: 22344487 PMCID: PMC3641145 DOI: 10.1039/c2lc21189k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
While sophisticated analyses have been performed using lab-on-chip devices, in most cases the sample preparation is still performed off chip. The global need for easy-to-use, disposable testing devices necessitates that sample processing is automated and that transport complexity between the processing and analytical components is minimal. We describe a complete sample manipulation unit for performing automated target capture, efficient mixing with reagents, and controlled target release in a microfluidic channel, using an array of spinning magnets. The "MagTrap" device consists of 6 pairs of magnets in a rotating wheel, situated immediately beneath the microchannel. Rotation of the wheel in the direction opposite to the continuous flow entraps and concentrates the bead-target complexes and separates them from the original sample matrix. As the wheel rotates and the active pair of magnets moves away from the microchannel, the beads are released and briefly flow downstream before being trapped and pulled upstream by the next pair of magnets. This dynamic and continuous movement of the beads ensures that the full surface area of each bead is exposed to reagents and prevents aggregation. The release of the target-bead complexes for further analysis is facilitated by reversing the rotational direction of the wheel to sweep the beads downstream. Sample processing with the MagTrap was demonstrated for the detection of E. coli in a range of concentrations (1 × 10(3), 1 × 10(4) and 1 × 10(6) cells ml(-1)). Results show that sample processing with the MagTrap outperformed the standard manual protocols, improving the detection capability while simultaneously reducing the processing time.
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13
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Zhao X, Dong T, Yang Z, Pires N, Høivik N. Compatible immuno-NASBA LOC device for quantitative detection of waterborne pathogens: design and validation. LAB ON A CHIP 2012; 12:602-612. [PMID: 22146918 DOI: 10.1039/c1lc20836e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Waterborne pathogens usually pose a global threat to animals and human beings. There has been a growing demand for convenient and sensitive tools to detect the potential emerging pathogens in water. In this study, a lab-on-a-chip (LOC) device based on the real-time immuno-NASBA (immuno-nucleic acid sequence-based amplification) assay was designed, fabricated and verified. The disposable immuno-NASBA chip is modelled on a 96-well ELISA microplate, which contains 43 reaction chambers inside the bionic channel networks. All valves are designed outside the chip and are reusable. The sample and reagent solutions were pushed into each chamber in turn, which was controlled by the valve system. Notably, the immuno-NASBA chip is completely compatible with common microplate readers in a biological laboratory, and can distinguish multiple waterborne pathogens in water samples quantitatively and simultaneously. The performance of the LOC device was demonstrated by detecting the presence of a synthetic peptide, ACTH (adrenocorticotropic hormone) and two common waterborne pathogens, Escherichia coli (E. coli) and rotavirus, in artificial samples. The results indicated that the LOC device has the potential to quantify traces of waterborne pathogens at femtomolar levels with high specificity, although the detection process was still subject to some factors, such as ribonuclease (RNase) contamination and non-specific adsorption. As an ultra-sensitive tool to quantify waterborne pathogens, the LOC device can be used to monitor water quality in the drinking water system. Furthermore, a series of compatible high-throughput LOC devices for monitoring waterborne pathogens could be derived from this prototype with the same design idea, which may render the complicated immuno-NASBA assays convenient to common users without special training.
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Affiliation(s)
- Xinyan Zhao
- Department of Micro and Nano Systems Technology, Faculty of Engineering and Marine Sciences, Vestfold University College, Tønsberg, Box 2243, N-3103, Norway
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14
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Barat D, Spencer D, Benazzi G, Mowlem MC, Morgan H. Simultaneous high speed optical and impedance analysis of single particles with a microfluidic cytometer. LAB ON A CHIP 2012; 12:118-26. [PMID: 22051732 DOI: 10.1039/c1lc20785g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We describe a microfluidic cytometer that performs simultaneous optical and electrical characterisation of particles. The microfluidic chip measures side scattered light, signal extinction and fluorescence using integrated optical fibres coupled to photomultiplier tubes. The channel is 80 μm high and 200 μm wide, and made from SU-8 patterned and sandwiched between glass substrates. Particles were focused into the analysis region using 1-D hydrodynamic focusing and typical particle velocities were 0.1 ms(-1). Excitation light is coupled into the detection channel with an optical fibre and focused into the channel using an integrated compound air lens. The electrical impedance of particles is measured at 1 MHz using micro-electrodes fabricated on the channel top and bottom. This data is used to accurately size the particles. The system is characterised using a range of different sized polystyrene beads (fluorescent and non-fluorescent). Single and mixed populations of beads were measured and the data compared with a conventional flow cytometer.
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Affiliation(s)
- David Barat
- School of Electronics and Computer Science, University of Southampton, Highfield, Southampton, SO17 1BJ, UK
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15
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Golden JP, Justin GA, Nasir M, Ligler FS. Hydrodynamic focusing--a versatile tool. Anal Bioanal Chem 2011; 402:325-35. [PMID: 21952728 DOI: 10.1007/s00216-011-5415-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/09/2011] [Accepted: 09/11/2011] [Indexed: 11/29/2022]
Abstract
The control of hydrodynamic focusing in a microchannel has inspired new approaches for microfluidic mixing, separations, sensors, cell analysis, and microfabrication. Achieving a flat interface between the focusing and focused fluids is dependent on Reynolds number and device geometry, and many hydrodynamic focusing systems can benefit from this understanding. For applications where a specific cross-sectional shape is desired for the focused flow, advection generated by grooved structures in the channel walls can be used to define the shape of the focused flow. Relative flow rates of the focused flow and focusing streams can be manipulated to control the cross-sectional area of the focused flows. This paper discusses the principles for defining the shape of the interface between the focused and focusing fluids and provides examples from our lab that use hydrodynamic focusing for impedance-based sensors, flow cytometry, and microfabrication to illustrate the breadth of opportunities for introducing new capabilities into microfluidic systems. We evaluate each example for the advantages and limitations integral to utilization of hydrodynamic focusing for that particular application.
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Affiliation(s)
- Joel P Golden
- Naval Research Laboratory, Center for Bio/Molecular Science and Engineering, Washington, DC 20375, USA
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16
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Erickson JS, Hashemi N, Sullivan JM, Weidemann AD, Ligler FS. In Situ Phytoplankton Analysis: There’s Plenty of Room at the Bottom. Anal Chem 2011; 84:839-50. [DOI: 10.1021/ac201623k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeffrey S. Erickson
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Code 6900, Washington, D.C. 20375-5438, United States
| | - Nastaran Hashemi
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Code 6900, Washington, D.C. 20375-5438, United States
| | - James M. Sullivan
- WET Laboratories, Inc., Department of Research, 70 Dean Knauss Drive, Narragansett, Rhode Island 02882, United States
| | - Alan D. Weidemann
- Hydro-Optics, Sensors, and Systems Section, Naval Research Laboratory, Code 7333, Stennis Space Center, Mississippi 39529-5004, United States
| | - Frances S. Ligler
- Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Code 6900, Washington, D.C. 20375-5438, United States
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Boyle DS, Hawkins KR, Steele MS, Singhal M, Cheng X. Emerging technologies for point-of-care CD4 T-lymphocyte counting. Trends Biotechnol 2011; 30:45-54. [PMID: 21798607 DOI: 10.1016/j.tibtech.2011.06.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 06/01/2011] [Accepted: 06/28/2011] [Indexed: 10/17/2022]
Abstract
A CD4 T-lymphocyte count determines eligibility for antiretroviral therapy (ART) in patients recently diagnosed with HIV and also monitors the efficacy of ART treatment thereafter. ART slows the progression of HIV to AIDS. In the developing world, CD4 tests are often performed in centralized laboratories, typically in urban areas. The expansion of ART programs into rural areas has created a need for rapid CD4 counting because logistical barriers can delay the timely dissemination of test results and affect patient care through delay in intervention or loss of follow-up care. CD4 measurement at the point-of-care (POC) in rural areas could help the facilitation of ART and monitoring of treatment. This review highlights recent technology developments with applications towards determining CD4 counts at the POC.
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Affiliation(s)
- David S Boyle
- Program for Appropriate Technology in Health (PATH), Seattle, WA 98121, USA.
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