In situ synthesis of gold-core silver-shell nanoparticles on bacterial cellulose for SERS detection of micro- and nanoplastic particles in vegetables

Abstract

Micro- and nanoplastic particles (MNPs) are ubiquitous environmental contaminants, raising significant concerns due to their potential health risks. There is an urgent need for highly sensitive detection methods, especially for complex food samples. This study presents a novel surface-enhanced Raman spectroscopy (SERS) sensor, developed through in situ synthesis of gold-core silver-shell (Au@Ag) nanoparticles on bacterial cellulose (BC), for detecting MNPs in leafy vegetables. The BC serves as both a biocompatible scaffold and an eco-friendly reducing agent, thereby facilitating the green synthesis of nanoparticles. The BC@Au@Ag sensor enabled reliable detection of polyethylene (PE) and polystyrene (PS) micro- and nanoplastics in kale samples at 4 mg kg⁻¹, while the theoretically estimated limits of detection, calculated from weighted regression analysis, were as low as 1.22 mg kg⁻¹ for PS and 3.95 mg kg⁻¹ for PE. Combined recovery and precision analyses confirm the reproducibility and robustness of the BC@Au@Ag SERS platform, demonstrating its suitability for sensitive and reliable monitoring of MNPs in complex food matrices.