Highly Sensitive Microarray Immunoassay for Multiple Mycotoxins on Engineered 3D Porous Silicon SERS Substrate with...

Area of Science:

• Nanotechnology and Materials Science
• Analytical Chemistry
• Biosensing

Background:

• Mycotoxin contamination poses significant risks to human health and food safety.
• Existing methods for mycotoxin detection often lack the required sensitivity, speed, or multiplexing capabilities.
• Surface-enhanced Raman spectroscopy (SERS) offers high sensitivity for molecular detection, but substrate optimization is crucial.

Purpose of the Study:

• To develop a high-throughput, rapid, and highly sensitive SERS microarray for simultaneous screening of multiple mycotoxins.
• To engineer an optimal three-dimensional silver nanoparticle porous silicon (3D AgNP-Psi) SERS substrate.
• To demonstrate the application of the developed SERS microarray in a protein microarray format for mycotoxin detection.

Main Methods:

• Fabrication of a 3D AgNP-Psi SERS substrate using electrochemical etching and magnetron sputtering.
• Optimization of substrate parameters including etching current density, waveform, and sputtering target thickness.
• Design of a protein microarray utilizing gold nanoparticle (AuNP) Raman tags and a competitive immunoassay on the 3D SERS substrate.

Main Results:

• The optimized 3D AgNP-Psi substrate achieved an enhancement factor of 2.3 × 10⁷ with superior near-field enhancement compared to gold nanoparticles.
• The SERS protein microarray demonstrated wide linear detection ranges for ochratoxin A (0.001-100 ng/mL), aflatoxin B₁ (0.01-100 ng/mL), and deoxynivalenol (0.001-10 ng/mL).
• The assay exhibited low limits of detection in the pg/mL range, along with good recovery rates, repeatability, and reproducibility.

Conclusions:

• A highly efficient and easily engineered 3D SERS protein microarray platform for multiplexed mycotoxin detection has been successfully developed.
• The developed SERS microarray offers significant advantages in terms of sensitivity, speed, and throughput for mycotoxin screening.
• This technology holds substantial potential for practical applications in food safety, environmental monitoring, and clinical diagnostics.