Development of an improved stationary liquid-phase lab-on-a-chip for the field monitoring of paralytic shellfish toxins

Abstract

A stationary liquid-phase lab-on-a-chip (SLP-LOC), in which magnetic particles are used as a solid phase, has been previously reported as a novel platform for immunoassay methods. The SLP-LOC had a simple structure with two chambers connected by a narrow channel. The assay was performed by transporting the particles from one chamber to the next while the liquid phases were in a stationary state. However, each chamber was frequently contaminated by other chamber materials because of the small volume of the channel. Consequently, in this work, we have developed a three-chamber SLP-LOC (3C-LOC) featuring an additional chamber containing a buffered washing solution positioned between the existing two chambers and connected by channels. The dimensions of the 3C-LOC were optimized to fit into a standard spectrophotometer cuvette holder, allowing the direct measurement of absorbance. The 3C-LOC exhibited improved washing efficiency, reliability, and sensitivity in an assay of standard saxitoxin samples. Furthermore, the method was used to effectively determine whether paralytic shellfish toxin (PST) levels in shellfish samples exceeded regulatory limits. The results of this study indicate that the 3C-LOC could provide a simple and rapid method to monitor PSTs in the field.

Magnetic Beads in Marine Toxin Detection: A Review

“…The LOD was around 3 µg/L, far below the regulatory level of PSP toxins (800 µg STX per kg shellfish). In 2017, Yu and Choi [29] improved the system by adding an extra washing chamber between the two existing ones, resulting in a decrease in the LOD to around 6 ng/L. CFP is a human intoxication caused by the ingestion of contaminated fish and is a worldwide health problem.…”

Label-Free Direct Detection of Saxitoxin Based on a Localized Surface Plasmon Resonance Aptasensor

“…These methods offer highly sensitive and accurate analytical performance; however, they also have disadvantages such as complex operating preprocesses, high cost, and requirement of professional operators. Therefore, simple, cost-effective, and efficient methods for monitoring of PSP toxins have been developed using diverse sensing platforms, e.g., lab-on-a-chip, surface plasmon resonance (SPR), electrochemistry, and fluorescence assay [16,17,18,19,20,21]. However, these PSP-sensing tools still face limitations, e.g., a relatively narrow linear detection range and decreasing signal-based analysis.…”