Sensitivity Validation of EWOD Devices for Diagnosis of Early Mortality Syndrome (EMS) in Shrimp Using Colorimetric LAMP–XO Technique

Abstract

Electrowetting-on-dielectric (EWOD) is a microfluidic technology used for manipulating liquid droplets at microliter to nanoliter scale. EWOD has the ability to facilitate the accurate manipulation of liquid droplets, i.e., transporting, dispensing, splitting, and mixing. In this work, EWOD fabrication with suitable and affordable materials is proposed for creating EWOD lab-on-a-chip platforms. The EWOD platforms are applied for the diagnosis of early mortality syndrome (EMS) in shrimp by utilizing the colorimetric loop-mediated isothermal amplification method with pH-sensitive xylenol orange (LAMP–XO) diagnosis technique. The qualitative sensitivity is observed by comparing the limit of detection (LOD) while performing the LAMP–XO diagnosis test on the proposed lab-on-a-chip EWOD platform, alongside standard LAMP laboratory tests. The comparison results confirm the reliability of EMS diagnosis on the EWOD platform with qualitative sensitivity for detecting the EMS DNA plasmid concentration at 102 copies in a similar manner to the common LAMP diagnosis tests.

Plasmodium knowlesi: the game changer for malaria eradication

“…Subsequently, Lau et al developed a species-specific LAMP approach that covered the five medically important parasites ( P. falciparum , P. vivax , P. malariae , P. ovale , and P. knowlesi ), with a detection limit of one copy/µL for P. vivax , P. falciparum , and P. malariae ; and ten copies/µL for P. knowlesi and P. ovale [ 113 ]. To facilitate the end point detection of LAMP, a variety of DNA intercalating dyes [ 113 – 115 ], fluorescent indicator dyes [ 116 , 117 ] and pH indicators [ 118 ] can be included in the LAMP assay. Recently, Lai et al has developed a SYBR green I LAMP assay for the detection of P. knowlesi by targeting the 18s rRNA gene, where a positive reaction is indicated by green colour whereas the negative reaction is indicated by orange colour [ 119 ].…”

Flow Analysis and Structural Optimization of Double-chamber Parallel Flexible Valve Micropump

“…𝛾 = 𝜒𝜀 (7) where ，∅ and 𝛹are shape functions used to represent the contact surfaces of the two-phase flow.…”

Flow Analysis and Structural Optimization of Double-Chamber Parallel Flexible Valve Micropumps

“…Yamamoto et al [9] discussed the influences of the droplet volume, the oil viscosity, the lubrication, and the thickness of liquid and solid dielectric layers on droplet velocity. The EWOD does not only find its application in micropumps; it has also been applied in other fields like the diagnosis of the early mortality syndrome in shrimp [10].…”