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Ahmad Zahidi AA, Chung DCK, Katariya M, Liew OW, Ng TW. Living specimens under field immobilization and smartphone microscopic observation. Microsc Res Tech 2019; 82:1741-1747. [DOI: 10.1002/jemt.23340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/20/2019] [Accepted: 06/24/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Alifa A. Ahmad Zahidi
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace EngineeringMonash University Clayton Victoria Australia
| | - Dwayne C. K. Chung
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace EngineeringMonash University Clayton Victoria Australia
| | - Mayur Katariya
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace EngineeringMonash University Clayton Victoria Australia
| | - Oi Wah Liew
- Centre for Translational MedicineCardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System Singapore
| | - Tuck Wah Ng
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace EngineeringMonash University Clayton Victoria Australia
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Lilyanna S, Ng EMW, Moriguchi S, Chan SP, Kokawa R, Huynh SH, Chong PCJ, Ng YX, Richards AM, Ng TW, Liew OW. Variability in Microplate Surface Properties and Its Impact on ELISA. J Appl Lab Med 2017; 2:687-699. [PMID: 33636870 DOI: 10.1373/jalm.2017.023952] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/18/2017] [Indexed: 11/06/2022]
Abstract
BACKGROUND Microplate-based immunoassays are widely used in clinical and research settings to measure a broad range of biomarkers present in complex matrices. Assay variability within and between microplates can give rise to false-negative and false-positive results leading to incorrect conclusions. To date, the contribution of microplates to this variability remains poorly characterized and described. This study provides new insights into variability in immunoassays attributable to surface characteristics of commercial microplates. METHODS Well-to-well assay variation in γ-treated and nontreated 96-well opaque microplates suitable for chemiluminescence assays was determined by use of a validated sandwich ELISA. Microplate surface characteristics were assessed by sessile drop contact angle measurements, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic force microscopy. RESULTS All microplate types tested exhibited vendor-specific assay response profiles; and "rogue" plates with very high intraassay variation and deviant mean assay responses were found. Within-plate, location-dependent bias in assay responses and variability in well contact angle were also observed. We demonstrate substantial differences in well-surface properties with putative effects on protein-coating reproducibility and hence consistency in immunoassay responses. A surface "cleaning" effect on manufacturing residues was attributed to γ-irradiation, and treated microplates manifest increased polar functionalities, surface roughness, and assay responses. CONCLUSIONS Our data suggest that tighter control of variability in surface roughness, wettability, chemistry, and level of residual contaminants during microplate preparation is warranted to improve consistency of ELISA assay read out.
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Affiliation(s)
- Shera Lilyanna
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Enoch Ming Wei Ng
- Laboratory for Optics & Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Australia
| | | | - Siew Pang Chan
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Ryohei Kokawa
- Global Application Development Center, Shimadzu Corporation, Japan
| | - So Hung Huynh
- Laboratory for Optics & Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Australia
| | - P C Jenny Chong
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - Yan Xia Ng
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
| | - A Mark Richards
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore.,Christchurch Heart Institute, Department of Medicine, University of Otago, Christchurch, New Zealand
| | - Tuck Wah Ng
- Laboratory for Optics & Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Australia
| | - Oi Wah Liew
- Cardiovascular Research Institute, Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore
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Lau CY, Zahidi AAA, Liew OW, Ng TW. A direct heating model to overcome the edge effect in microplates. J Pharm Biomed Anal 2014; 102:199-202. [PMID: 25289516 DOI: 10.1016/j.jpba.2014.09.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/10/2014] [Accepted: 09/13/2014] [Indexed: 11/25/2022]
Abstract
Array-based tests in a microplate format are complicated by the regional variation in results of the outer against the inner wells of the plate. Analysis of the evaporation mechanics of sessile drops showed that evaporation rate increase with temperature was due to changes in the heat of vaporization, density and diffusion coefficient. In simulations of direct bottom heating of standard microplates, considerable heat transfer via conduction from the side walls was found to be responsible for lower temperatures in the liquid in wells close to the edge. Applying a two temperature heating mode, 304 K at the side compared to 310 K at the bottom, allowed for a more uniform temperature distribution. Transparency microplates were found to inherently possess immunity to the edge effect problem due to the presence of air between the liquid and solid wall.
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Affiliation(s)
- Chun Yat Lau
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Alifa Afiah Ahmad Zahidi
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Oi Wah Liew
- Cardiovascular Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Centre for Translational Medicine, 14 Medical Drive, Singapore 117599, Singapore
| | - Tuck Wah Ng
- Laboratory for Optics and Applied Mechanics, Department of Mechanical & Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia.
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