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Mukunda DC, Rodrigues J, Joshi VK, Raghushaker CR, Mahato KK. A comprehensive review on LED-induced fluorescence in diagnostic pathology. Biosens Bioelectron 2022; 209:114230. [PMID: 35421670 DOI: 10.1016/j.bios.2022.114230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 03/19/2022] [Accepted: 03/25/2022] [Indexed: 11/02/2022]
Abstract
Sensitivity, specificity, mobility, and affordability are important criteria to consider for developing diagnostic instruments in common use. Fluorescence spectroscopy has been demonstrating substantial potential in the clinical diagnosis of diseases and evaluating the underlying causes of pathogenesis. A higher degree of device integration with appropriate sensitivity and reasonable cost would further boost the value of the fluorescence techniques in clinical diagnosis and aid in the reduction of healthcare expenses, which is a key economic concern in emerging markets. Light-emitting diodes (LEDs), which are inexpensive and smaller are attractive alternatives to conventional excitation sources in fluorescence spectroscopy, are gaining a lot of momentum in the development of affordable, compact analytical instruments of clinical relevance. The commercial availability of a broad range of LED wavelengths (255-4600 nm) has opened up new avenues for targeting a wide range of clinically significant molecules (both endogenous and exogenous), thereby diagnosing a range of clinical illnesses. As a result, we have specifically examined the uses of LED-induced fluorescence (LED-IF) in preclinical and clinical evaluations of pathological conditions, considering the present advancements in the field.
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Affiliation(s)
| | - Jackson Rodrigues
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka-576104, India
| | - Vijay Kumar Joshi
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka-576104, India
| | - Chandavalli Ramappa Raghushaker
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka-576104, India
| | - Krishna Kishore Mahato
- Department of Biophysics, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka-576104, India.
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2
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Twenty years of amino acid determination using capillary electrophoresis: A review. Anal Chim Acta 2021; 1174:338233. [DOI: 10.1016/j.aca.2021.338233] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/28/2022]
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3
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Harmon DM, Chen CF, Halford JH. Portable Fluorescence Detection Platform with Integrating Sphere. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:2889-2892. [PMID: 30441005 DOI: 10.1109/embc.2018.8512864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A platform coupled with an integrating sphere for portable fluorescence detection was presented in this paper. The detector under testing has a demonstrated lower limit of detection 0.4 nM for detecting fluorescein solutions and 0.00128 ng/mL for detecting SYBR-Green stained dsDNA in this preliminary work. The signal-to-noise ratio analysis suggests that the limit of detection could be even lower than presented herein.
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Rausch KM, Zhu D. Determination of Protein Content in Alhydrogel ®-Based Vaccines by O-Phthalaldehyde Assay. Methods Mol Biol 2017; 1494:263-271. [PMID: 27718200 DOI: 10.1007/978-1-4939-6445-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The quantification of antigens adsorbed to aluminum-based adjuvants (alum) typically involves a method that first extracts antigen from the alum followed by the quantification of the antigen available in the extract. Extraction procedures often result in less than 100 % desorption of the antigen from the alum adjuvant and may alter the conformation of the antigen, reducing the accuracy of the subsequent method used for quantification. There is no generic method available for directly assessing the protein content when formulated on alum. Here we offer a method that can directly quantify protein adsorbed to Alhydrogel® using a simple fluorescence assay that is highly accurate and reproducible for Alhydrogel® formulations containing 25-400 μg/mL of antigen.
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Affiliation(s)
- Kelly M Rausch
- Laboratory of Malaria Immunology and Vaccinology, National Institutes of Allergy and Infectious Disease, National Institutes of Health, 5640 Fishers Lane, Rockville, MD, 20852, USA.
| | - Daming Zhu
- Laboratory of Malaria Immunology and Vaccinology, National Institutes of Allergy and Infectious Disease, National Institutes of Health, 5640 Fishers Lane, Rockville, MD, 20852, USA.
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Practical considerations for preparing polymerized phospholipid bilayer capillary coatings for protein separations. Anal Chim Acta 2013; 772:93-8. [PMID: 23540253 DOI: 10.1016/j.aca.2013.02.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 11/27/2012] [Accepted: 02/14/2013] [Indexed: 11/21/2022]
Abstract
Phosphorylcholine (PC) based phospholipid bilayers have proven useful as capillary coating materials due to their inherent resistance to non-specific protein adsorption. The primary limitation of this important class of capillary coatings remains the limited long-term chemical and physical stability of the coatings. Recently, a method for increasing phospholipid coating stability in fused silica capillaries via utilization of polymerized, synthetic phospholipids was reported. Here, we expand upon these studies by investigating polymerized lipid bilayer capillary coatings with respect to separation performance including run-to-run, day-to-day and column-to-column reproducibility and long-term stability. In addition, the effects of pH and capillary inner diameter on polymerized phospholipid coated capillaries were investigated to identify optimized coating conditions. The coatings are stabilized for protein separations across a wide range of pH values (4.0-9.3), a unique property for capillary coating materials. Additionally, smaller inner diameter capillaries (≤50 μm) were found to yield marked enhancements in coating stability and reproducibility compared to wider bore capillaries, demonstrating the importance of capillary size for separations employing polymerized phospholipid coatings.
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Automated method for analysis of tryptophan and tyrosine metabolites using capillary electrophoresis with native fluorescence detection. Anal Bioanal Chem 2013; 405:2451-9. [PMID: 23307134 DOI: 10.1007/s00216-012-6685-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 11/28/2012] [Accepted: 12/20/2012] [Indexed: 02/04/2023]
Abstract
Capillary electrophoresis (CE) with laser-induced native fluorescence (LINF) detection offers the ability to characterize low levels of selected analyte classes, depending on the excitation and emission wavelengths used. Here a new automated CE-LINF system that provides deep ultraviolet (DUV) excitation (224 nm) and variable emission wavelength detection was evaluated for the analysis of small molecule tryptophan- and tyrosine-related metabolites. The optimized instrument design includes several features that increase throughput, lower instrument cost and maintenance, and decrease complexity when compared with earlier systems using DUV excitation. Sensitivity is enhanced by using an ellipsoid detection cell to increase the fluorescence collection efficiency. The limits of detection ranged from 4 to 30 nmol/L for serotonin and tyrosine, respectively. The system demonstrated excellent linearity over several orders of magnitude of concentration and intraday precision from 1-11 % relative standard deviation (RSD). The instrument's performance was validated via tryptophan and serotonin characterization using tissue extracts from the mammalian brain stem, with RSDs of less than 10 % for both metabolites. The flexibility and sensitivity offered by DUV laser excitation and tunable emission enables a broad range of small-volume measurements.
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Gallagher ES, Comi TJ, Braun KL, Aspinwall CA. Online photolytic optical gating of caged fluorophores in capillary zone electrophoresis utilizing an ultraviolet light-emitting diode. Electrophoresis 2012; 33:2903-10. [PMID: 22911376 DOI: 10.1002/elps.201200279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 06/23/2012] [Accepted: 06/25/2012] [Indexed: 11/11/2022]
Abstract
Photolytic optical gating (POG) facilitates rapid, on-line and highly sensitive analyses, though POG utilizes UV lasers for sample injection. We present a low-cost, more portable alternative, employing an ultraviolet light-emitting diode (UV-LED) array to inject caged fluorescent dyes via photolysis. Utilizing the UV-LED array, labeled amino acids were injected with nanomolar limits of detection (270 ± 30 nM and 250 ± 30 nM for arginine and citrulline, respectively). When normalized for the difference in light intensity, the UV-LED array provides comparable sensitivity to POG utilizing UV lasers. Additionally, the UV-LED array yielded sufficient beam quality and stability to facilitate coupling with a Hadamard transform, resulting in increased sensitivity. This work shows, for the first time, the use of an UV-LED for online POG with comparable sensitivity to conventional laser sources but at a lower cost.
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Affiliation(s)
- Elyssia S Gallagher
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA
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Kulp M, Bragina O, Kogerman P, Kaljurand M. Capillary electrophoresis with LED-induced native fluorescence detection for determination of isoquinoline alkaloids and their cytotoxicity in extracts of Chelidonium majus L. J Chromatogr A 2011; 1218:5298-304. [PMID: 21726876 DOI: 10.1016/j.chroma.2011.06.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 06/03/2011] [Accepted: 06/06/2011] [Indexed: 10/18/2022]
Abstract
In this study, we introduced a simple and sensitive method of capillary electrophoresis with ultraviolet light-emitting diode-induced native fluorescence (UV-LEDIF) detection for the determination of isoquinoline alkaloids in extracts of Chelidonium majus L. Samples were extracted with acidic methanol and the extracts were directly analysed by CE. Simultaneous determination of protopine, chelidonine, coptisine, sanguinarine, allocryptopine, chelerythrine and stylopine was performed in 20mM phosphate buffer (pH 3.1). The baseline separation of these alkaloids was finished within 20 min. As these alkaloids have native fluorescence, they were directly detected using the commercially available UV light emitting diode without troublesome fluorescent derivatisation. Satisfactory LOD values were obtained for the studied compounds considering their appearance in natural extracts. Lower limits of detection were 0.05 μg/mL for protopine, 0.06 μg/mL for stylopine and allocryptopine, 0.07 μg/mL for chelidonine, 0.22 μg/mL for sanguinarine, 1.7 μg/mL for chelerythrine and 5.5 μg/mL for coptisine. The developed method was successfully applied to determine the contents of seven alkaloids in the aerial parts of Chelidonium majus L, which varied from 0.025 to 0.763% (w/w). Also, to demonstrate the potential of the proposed CE method, an estimation of the cytotoxic properties of selected Celandine alkaloids in a natural extract was carried out.
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Affiliation(s)
- Maria Kulp
- Tallinn University of Technology, Department of Chemistry, Akadeemia tee 15, Tallinn, Estonia.
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Perry M, Li Q, Kennedy RT. Review of recent advances in analytical techniques for the determination of neurotransmitters. Anal Chim Acta 2009; 653:1-22. [PMID: 19800472 PMCID: PMC2759352 DOI: 10.1016/j.aca.2009.08.038] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 08/25/2009] [Accepted: 08/27/2009] [Indexed: 12/18/2022]
Abstract
Methods and advances for monitoring neurotransmitters in vivo or for tissue analysis of neurotransmitters over the last five years are reviewed. The review is organized primarily by neurotransmitter type. Transmitter and related compounds may be monitored by either in vivo sampling coupled to analytical methods or implanted sensors. Sampling is primarily performed using microdialysis, but low-flow push-pull perfusion may offer advantages of spatial resolution while minimizing the tissue disruption associated with higher flow rates. Analytical techniques coupled to these sampling methods include liquid chromatography, capillary electrophoresis, enzyme assays, sensors, and mass spectrometry. Methods for the detection of amino acid, monoamine, neuropeptide, acetylcholine, nucleoside, and soluble gas neurotransmitters have been developed and improved upon. Advances in the speed and sensitivity of these methods have enabled improvements in temporal resolution and increased the number of compounds detectable. Similar advances have enabled improved detection at tissue samples, with a substantial emphasis on single cell and other small samples. Sensors provide excellent temporal and spatial resolution for in vivo monitoring. Advances in application to catecholamines, indoleamines, and amino acids have been prominent. Improvements in stability, sensitivity, and selectivity of the sensors have been of paramount interest.
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Affiliation(s)
- Maura Perry
- University of Michigan, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109-1055, USA
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Zhu D, Saul A, Huang S, Martin LB, Miller LH, Rausch KM. Use of o-phthalaldehyde assay to determine protein contents of Alhydrogel-based vaccines. Vaccine 2009; 27:6054-9. [PMID: 19660590 DOI: 10.1016/j.vaccine.2009.07.067] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/14/2009] [Accepted: 07/20/2009] [Indexed: 11/30/2022]
Abstract
Aluminum based adjuvants (alum), including aluminum hydroxide (Alhydrogel) and aluminum phosphate are the most commonly used adjuvant in the US. In order to ensure quality of vaccines, regulatory authorities require evaluation of antigen content in final vaccine products. Currently, there are no generic methods available for the determination of protein content in alum-based vaccines. Aluminum hydroxide gels exist as particles in solution, which interfere with direct quantitation of protein content in formulations using assays such as Lowry, BCA or Bradford protein assay. The present study adapts a simple fluorescent assay to directly (without the need for antigen extraction) determine antigen content on Alhydrogel with accuracy and sensitivity using the o-phthalaldehyde (OPA) reagent. Malaria vaccine candidates AMA1-C1/Alhydrogel, AMA1-C2/Alhydrogel, MSP1(42)-3D7/Alhydrogel, MSP1(42)-C1/Alhydrogel or BSAM-2/Alhydrogel were used as model formulations. The results of the present study show that the OPA assay is highly accurate (87-100%), reproducible, and simple with a linear detection range of 25-400 microg/mL for Alhydrogel vaccines (except for MSP1(42)-C1, which has a linear detection range of 31.25-500 microg/mL). This assay has proven to be highly useful in our laboratory and been used in routine vaccine quality control processes.
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Affiliation(s)
- Daming Zhu
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Disease, National Institutes of Health, 5640 Fishers Lane, Rockville, MD 20852, USA.
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Link M, Schulze P, Belder D, Wolfbeis OS. New diode laser-excitable green fluorescent label and its application to detection of bovine serum albumin via microchip electrophoresis. Mikrochim Acta 2009. [DOI: 10.1007/s00604-009-0169-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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12
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Xiao D, Yan L, Yuan H, Zhao S, Yang X, Choi MMF. CE with LED-based detection: An update. Electrophoresis 2009; 30:189-202. [DOI: 10.1002/elps.200800415] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Silva M. Micellar electrokinetic chromatography: Methodological and instrumental advances focused on practical aspects. Electrophoresis 2009; 30:50-64. [DOI: 10.1002/elps.200800414] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Improving detection in capillary electrophoresis with laser induced fluorescence via a bubble cell capillary and laser power adjustment. Biomed Chromatogr 2009; 23:42-7. [DOI: 10.1002/bmc.1080] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kostal V, Katzenmeyer J, Arriaga EA. Capillary electrophoresis in bioanalysis. Anal Chem 2008; 80:4533-50. [PMID: 18484738 DOI: 10.1021/ac8007384] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Vratislav Kostal
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Poinsot V, Rodat A, Gavard P, Feurer B, Couderc F. Recent advances in amino acid analysis by CE. Electrophoresis 2008; 29:207-23. [DOI: 10.1002/elps.200700482] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Schmid S, Macka M, Hauser PC. UV-absorbance detector for HPLC based on a light-emitting diode. Analyst 2008; 133:465-9. [DOI: 10.1039/b715681b] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yamamoto D, Kaneta T, Imasaka T. Postcolumn reactor using a laser-drilled capillary for light-emitting diode-induced fluorescence detection in CE. Electrophoresis 2007; 28:4143-9. [DOI: 10.1002/elps.200700274] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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