Collapse-enhanced SERS effect of self-crosslinked plasmonic starch aerogels for sensitive detection of food contaminants.

A flexible 3D plasmonic starch aerogel substrate was fabricated for susceptible detection of thiabendazole (TBZ) and doxycycline hydrochloride (DH). Based on the unique structure features of starch, an aerogel with high porosity and a large specific surface area was formed without any extra cross-linking agents. Silver nanoparticles (Ag NPs) uniformly distribute throughout starch aerogel and generate dense hot spots while aerogel structure collapses, which leads to significant SERS enhancement. The as-prepared aerogel substrate exhibits good SERS activity with a low detection limit of 1 × 10-10 M for rhodamine 6G and 1 μg/L for 4-Aminothiophenol (4-ATP). In practical application for real sample, the TBZ residue on the surface of citrus was successfully detected by wipe sampling, with a good recovery rate of 96.2 %-98.8 % and a low limit of detection (LOD) of 0.031 mg/L range from 0.1 to 100 mg/L. The substrate also exhibited excellent performance in detecting DH in chicken, with recovery rates ranging from 96.9 % to 98.1 %. The LOD was 0.066 mg/L, and the detection range spanned from 0.1 to 100 mg/L. Results demonstrate that the prepared aerogel is an ideal material as a SERS substrate due to its unique properties such as strong adsorption capacity, dense hot spot, and ease of use. Therefore, the developed SERS platform-based flexible 3D plasmonic aerogel substrate paves a new avenue for highly sensitive SERS detection in the field of food safety.