A Gold Nanoparticle-Based Cortisol Aptasensor for Non-Invasive Detection of Fish Stress

Area of Science:

• Environmental Science
• Biotechnology
• Aquaculture Science

Background:

• Cortisol is a critical stress biomarker in fish, vital for monitoring welfare and productivity in aquaculture.
• Current cortisol detection methods often require invasive sampling, limiting real-time stress assessment.
• Optimizing aquaculture practices necessitates non-invasive, sensitive stress monitoring tools.

Purpose of the Study:

• To develop a non-invasive gold nanoparticle (AuNP)-based aptasensor for detecting cortisol in fish tank water.
• To achieve sensitive detection of picomolar cortisol concentrations in complex aquaculture environments.
• To provide a tool for real-time stress monitoring, enhancing fish welfare and productivity.

Main Methods:

• Conjugation of a cortisol-specific DNA aptamer to gold nanoparticles (AuNPs) with a blocker molecule (CALNN).
• Utilizing magnesium chloride (MgCl2)-induced aggregation for cortisol detection, based on aptamer structural changes and steric stabilization.
• Validation of the aptasensor using High-Performance Liquid Chromatography (HPLC) on recirculating aquaculture system (RAS) water samples.

Main Results:

• The developed aptasensor achieved a limit of detection (LOD) of 100 pM for cortisol within 35 minutes.
• The sensor demonstrated stability in complex fish tank water matrices.
• Validated sensor successfully detected cortisol level changes induced by different stress paradigms in RAS water samples.

Conclusions:

• The gold nanoparticle-based aptasensor provides a sensitive and non-invasive method for fish stress monitoring.
• This on-site deployable sensor enables real-time cortisol detection, crucial for optimizing aquaculture practices.
• The technology holds significant potential for improving fish welfare and aquaculture productivity through effective stress management.