Gecko-Inspired Nanotentacle Surface-Enhanced Raman Spectroscopy Substrate for Sampling and Reliable Detection of Pesticide Residues in Fruits and Vegetables.

Rapid sampling and multicomponent detection are crucial for monitoring of pesticide residues analysis. Here, a gecko-inspired nanotentacle surface-enhanced Raman spectroscopy (G-SERS) platform is proposed for the first time for the simultaneous detection of three kinds of pesticides via a simple and intuitive "press and peeled-off" approach. The G-SERS platform obtained from seeding deposition of silver nanoparticles (Ag NPs) on 3D PDMS nanotentacle array is flexible and free-standing. Compared with other substrates, this G-SERS substrate can simultaneously provide outstanding SERS activity (enhancement factor = 1.2 × 107), superior reproducibility (RSD = 5.8%) and countless flexible nanoscale "tentacles" (∼6.7 × 108/cm2). Moreover, the high density of "tentacles" can freely approach the microarea and enable efficient target collection, which were confirmed by SEM and HPLC. By direct sampling from cucumber, apple, and grape surfaces, thiram (TMTD), methyl parathion (MPT), malachite green (MG), and their multiple components have been rapidly and reliably determined. For example, under the optimal conditions, a sensitivity of 1.6 ng/cm2 (S/N = 3) for TMTD was obtained on apple peels with a correlation coefficient (R) of 0.99. Therefore, the G-SERS substrate could offer a great practical potential for on-spot identification of various pesticide residues on real samples.