An effective established biosensor of bifunctional probes-labeled AuNPs combined with LAMP for detection of fish pathogen Streptococcus iniae

Abstract

In purpose of valid Streptococcus iniae detection, we established a colorimetric biosensor using gold nanoparticles (AuNPs) labeled with dual functional probes and along with loop-mediated isothermal amplification (LAMP) assay (LAMP-AuNPs). Based on the characteristics of self-aggregation and bio-conjugation with ligands, AuNPs were chosen for observable color change in tandem with LAMP amplification method to reach high sensitivity and easy operation. Meanwhile, the improvement of dual probes that could fully utilize the LAMP product gave the biosensor a stable result exhibition. LAMP-AuNPs targeting gene ftsB, one of the ATP transporter-related genes, turned out favorable specificity in cross reaction among other fish pathogens. The detect limit of 10 CFU revealed a better sensitivity compared with polymerase chain reaction (PCR) method and AuNPs lateral flow test strip (LFTS). It was also proved to be effective by zebrafish infection model trials with less than 2-h time consumption and nearly no devices which make it a convenient biosensor for point-to-care S. iniae detection.

Recent developments towards portable point-of-care diagnostic devices for pathogen detection

“…This means that amplification is performed at a constant temperature, reducing the need for expensive thermal cycler and skilled personnel as well as shortening reaction time. Some of the isothermal amplification methods that have been introduced are loop-mediated isothermal amplification (LAMP) [34][35][36] , helicase-dependent amplification (HAD) 37 , isothermal strand displacement amplification (SDA) 38 , rolling circle amplification (RCA) 39 and signal-mediated amplification of RNA technology (SMART) 40 . Among all these techniques LAMP appeared to be popular for pathogen detection as it is capable of amplifying medium-to long-range of targeted nucleic acid strands with high efficiency, sensitivity, specificity and stability [41][42][43][44] .…”

“…In this study, authors were able to detect the LOD by 10 2 CFU which is much sensitive than normal PCR and conventional lateral flow strip process. Additionally, the whole process of detection took place less than 2h 39 . Many researchers have combined LAMP method with electrochemical sensor (E-Sensor) to achieve better sensitivity and good reproducibility.…”

Simultaneous detection of multiple bacterial and viral aquatic pathogens using a fluorogenic loop‐mediated isothermal amplification‐based dual‐sample microfluidic chip

“…Microfluidics is a technology for manipulating the precise transport of fluids at micrometre or nanometre scales, with the objectives of miniaturizing the equipment, simplifying the operation, preventing contamination and reducing the cost (Haeberle & Zengerle, 2007;Janasek et al, 2006;Pires et al, 2020). Therefore, microfluidic chips integrated with LAMP have been considered for detection of aquatic pathogens (Chang et al, 2013;Siddique et al, 2019;Wang et al, 2011;Zhou et al, 2014Zhou et al, , 2018. In our preliminary study, an on-chip LAMP method for rapid detection of 10 pathogenic bacteria in aquatic animals was developed.…”

Colorimetric sensing of iodide ions based on unmodified gold nanoparticles and the distinctive antiaggregation‐to‐aggregation process

“…[ 1,2 ] Gold nanoparticles (AuNPs), as one of the most important metal nanomaterials, have also attracted much attention due to their unique electrical, optical, physical, and chemical properties, such as easy synthesis, high surface‐to‐volume ratio, high extinction coefficients, strong distance dependent optical features, excellent biocompatibility and suitability for surface functionalization [ 3 ] , which provide numerous possibilities for sensing and quantification purposes. So far, various AuNP‐based sensors have been successfully applied to detect different substances (metal ions [ 4–6 ] , anions [ 7,8 ] proteins [ 9,10 ] , small molecules [ 11,12 ] and pathogens [ 13,14 ] ). However, these methods of detecting anions have been relatively less successful compared with other methods and most of the methods needed to modify the AuNP surface, this made the experimental procedure tedious and time‐consuming.…”