SERS using two-photon polymerized nanostructures for mycotoxin detection.

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Surface Enhanced Raman Spectroscopy (SERS) requires advanced nanostructures for sensitive chemical and biological detection.
• Flexible design and fabrication of nanostructures with tailored optical properties are crucial for SERS applications.

Purpose of the Study:

• To fabricate and characterize nano-pillar arrays as SERS substrates for mycotoxin detection.
• To simulate and experimentally validate the electromagnetic field enhancement of these nanostructures.
• To determine the limit of detection and assess the discrimination capabilities for specific mycotoxins.

Main Methods:

• Fabrication of nano-pillar arrays (200-600 nm) using two-photon polymerization.
• Simulation of electric field enhancement using Finite-Difference Time-Domain (FDTD) modeling, incorporating Atomic Force Microscopy (AFM) data.
• Experimental validation using Rhodamine B solutions and mycotoxin samples (deoxynivalenol, fumonisin b1).
• Analysis of SERS data using Principal Component Analysis (PCA).

Main Results:

• The 200 nm nano-pillar array exhibited the highest Enhancement Factor (EF) in both simulations and experiments.
• A limit of detection of 0.55 μM was achieved for Rhodamine B using the 200 nm nano-pillar array.
• Successful discrimination of deoxynivalenol (1 ppm) and fumonisin b1 (1.25 ppm) was demonstrated.

Conclusions:

• Nano-pillar arrays fabricated by two-photon polymerization serve as effective SERS substrates for mycotoxin detection.
• The 200 nm nano-pillar array offers superior sensitivity and a low limit of detection.
• This versatile fabrication approach provides new avenues for material characterization in chemical and biological sensing.