A novel microfluidic system for the sensitive and cost-effective detection of okadaic acid in mussels

Abstract

Okadaic acid (OA) is produced by marine dinoflagellates and it can be easily accumulated in the shellfish, causing intoxications when consumed by humans. Consequently, there is a need of sensitive,...

Ultrasensitive Picomolar Detection of Aqueous Acids in Microscale Fluorescent Droplets

“…Accordingly, after 25 min and using a single image pixel, we find that S = 0.045 nM −1 and σ noise is 0.002. With these values, the LoD is 1.3 × 10 −10 M. If we instead find the signal by averaging over 100 image pixels near the center of the droplets, the noise was lowered to 0.0005 and the resulting LoD was 3.1 × 10 −11 M. This is significantly better than previous fluorescence sensing-based strategies for acid detection, 13,14,16,34 and is even competitive with chemical sensing by more advanced and expensive methods such as surfaceenhanced Raman scattering for the detection of fluorescent dyes. 36 To our knowledge, the previous lowest LoD for fluorescent droplets was 1.9 nM; 34 while an impressive demonstration, the LoD for analyte detection was 2 orders of magnitude larger and it required more complicated and expensive equipment and analysis.…”

“…Colorimetric sensing is based on optical absorption changes and has yielded calculated LoDs as low as 11.6 nM for enzyme immobilization and detection of okadaic acid. 13 Fluorescence sensing strategies appear to have some of the lowest calculated LoDs so far, with reports into the single nanomolar range. 14 Further decreasing the LoD has proven challenging, however, because of detector noise and low light levels or weak sensing signals.…”

“…Electrochemical sensors for various acids are based on current or resistance measurements and have extrapolated limits of detection (LoDs) mainly in the micromolar regime or slightly below , (see Table ). Colorimetric sensing is based on optical absorption changes and has yielded calculated LoDs as low as 11.6 nM for enzyme immobilization and detection of okadaic acid . Fluorescence sensing strategies appear to have some of the lowest calculated LoDs so far, with reports into the single nanomolar range .…”

Sensitive detection of the okadaic acid marine toxin in shellfish by Au@Pt NPs/horseradish peroxidase dual catalysis immunoassay

“…According to ref. 37, shellfish samples including oysters, clams, and mussels were prepared. Briefly, 1 g of shellfish samples were disrupted in 5.0 mL 95% alcohol solution and homogenized by using an ultrasonic cell pulveriser for 1–2 min.…”

Sensitive time-resolved fluoroimmunoassay for the quantitative detection of okadaic acid

“…In recent years, some novel detection methods have also been developed. For example, the colorimetric detection system was established by fixing protein phosphatase 1 (PP1) in a microfluidic chamber modified by Al 2 O 3 sol-gel to determine the inhibitory effect of OA on PP1; the Au@Pt/HRP immunoassay for OA detection was established by using the dual catalytic action of Au@Pt NPs and HRP on TMB-H 2 O 2 (Castanheira et al, 2021;Tian et al, 2022). Among the detection methods, immunoassays are proven to be convenient, sensitive, cost-effective, and suitable for highthroughput screening (Wang and Xianyu, 2022).…”