Layer-by-Layer Biopolymer Assembly for the In Situ Fabrication of AuNP Plasmonic Paper-A SERS Substrate for Food Adulteration Detection

Nopparat Viriyakitpattana; Chanoknan Rattanabut; Chutiparn Lertvachirapaiboon; Dechnarong Pimalai; Suwussa Bamrungsap

doi:10.1021/acsomega.3c05966

Layer-by-Layer Biopolymer Assembly for the In Situ Fabrication of AuNP Plasmonic Paper-A SERS Substrate for Food Adulteration Detection

ACS Omega. 2024 Feb 20;9(9):10099-10109. doi: 10.1021/acsomega.3c05966. eCollection 2024 Mar 5.

Authors

Nopparat Viriyakitpattana^{1

2}, Chanoknan Rattanabut¹, Chutiparn Lertvachirapaiboon¹, Dechnarong Pimalai¹, Suwussa Bamrungsap¹

Affiliations

¹ National Nanotechnology Center, National Science and Technology Development Agency, Thailand Science Park, Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand.
² Thai Packaging Centre, Thailand Institute of Scientific and Technological Research, Phahonyothin Road, Chatuchak, Bangkok 10900, Thailand.

Abstract

Here, we introduce an environmentally friendly approach to fabricate a simple and cost-effective plasmonic paper for detecting food additives using surface-enhanced Raman spectroscopy (SERS). The plasmonic paper is fabricated by in situ growth of gold nanoparticles (AuNPs) on filter paper (FP). To facilitate this green fabrication process, we applied a double-layered coating of biopolymers, chitosan (CS) and alginate (ALG), onto the FP using a layer-by-layer (LbL) assembly through electrostatic interactions. Compared to single-layer biopolymer coatings, double-layered biopolymer-coated paper, ALG/CS/FP, significantly improves the reduction properties. Consequently, effective in situ growth of AuNPs can be achieved as seen in high density of AuNP formation on the substrate. The resulting plasmonic paper provides high SERS performance with an enhancement factor (EF) of 5.7 × 10¹⁰ and a low limit of detection (LOD) as low as 1.37 × 10^-12 M 4-mercaptobenzoic acid (4-MBA). Furthermore, it exhibits spot-to-spot reproducibility with a relative standard deviation (RSD) of 8.2% for SERS analysis and long-term stability over 50 days. This paper-based SERS substrate is applied for melamine (MEL) detection with a low detection limit of 0.2 ppb, which is sufficient for monitoring MEL contamination in milk based on food regulations. Additionally, we demonstrate a simultaneous detection of β-agonists, including ractopamine (RAC) and salbutamol (SAL), exhibiting the multiplexing capability and versatility of the plasmonic paper in food contaminant analysis. The development of this simple plasmonic paper through the LbL biopolymer assembly not only paves the way for novel SERS substrate fabrication but also broadens the application of SERS technology in food contaminant monitoring.