Development of a label-free-SERS gold nanoaptasensor for the accessible determination of ochratoxin A

Nanomaterials use in traditional spectroscopic assays has enabled the development of more sensitive and accessible methods with wider-range of applications. Usually, the sensitivity of nanosensors is improved through the incorporation of labels or by inducing nanoparticles aggregation. Herein, we present the development of a label-free, selective, reliable, and affordable gold nanoprisms aptasensor to detect the content of ochratoxin A (OTA) in suspension by surface-enhanced Raman spectroscopy (SERS). Label-free SERS provides a molecular signature of the aptamer-OTA complex used and enables to discriminate OTA solutions from 10 to 250 ppb (25–620 nM) with multivariate analysis. This label-free nanoaptasensing system represents a new possibility for simpler and more reliable and accessible procedures for OTA determination. •A gold nanoaptasensor in solution was developed using a simple preparation of nanoprisms and a portable Raman spectrometer.•This nanoaptasensor provides a molecular fingerprint of the aptamer-OTA complex without the presence of any additional label.•This detection system in combination with PLS analysis allows label-free SERS discrimination of 10-250 ppb OTA in solution.•This selective and reproducible nanoaptasensor shows good performance with wheat and coffee samples.