Tailored Au@Ag NPs for rapid ractopamine detection in pork: optimizing size for enhanced SERS signals

Authors: YIN, TIANZHEN - China Agricultural University; PENG, YANKUN - China Agricultural University; LI, YONGYN - China Agricultural University; NIE, SEN - China Agricultural University; LI, RONGJIAO - China Agricultural University; CHEN, YAHUI - China Agricultural University; ZUO, JIEWEN - China Agricultural University; Chao, Kuanglin

Submitted to: Food Bioscience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2024
Publication Date: 11/15/2024
Citation: Yin, T., Peng, Y., Li, Y., Nie, S., Li, R., Chen, Y., Zuo, J., Chao, K. 2024. Tailored Au@Ag NPs for rapid ractopamine detection in pork: optimizing size for enhanced SERS signals. Food Bioscience. 59: Article e104082. https://doi.org/10.1016/j.fbio.2024.104082.
DOI: https://doi.org/10.1016/j.fbio.2024.104082

Interpretive Summary: Ractopamine is a veterinary drug which promotes leaner meat by reducing fat content and improving the utilization of dietary nutrients in swine and cattle. The presence of veterinary drug residues in meat products has become a growing concern because of the adverse health risks and regulatory implications. Surface-enhanced Raman spectroscopy (SERS) method is an emerging technique which provides highly sensitive and selective detection by enhancing the Raman signal intensity of a sample adsorbed on gold nanoparticles. Compared to standard analytical chemistry methods, SERS offers the advantages of high sensitivity, rapid detection, and low cost. In this study, we have developed a new nanoparticle substrate for SERS-based detection of ractopamine in lean meat additives. The SERS signal of ractopamine was significantly enhanced and a quantitative analysis model with high sensitivity and selectivity was developed. This rapid screening technology provides a direct and practical method for detecting ractopamine in meats without the requirement of isolating, extracting, or concentrating the sample before obtaining a measurement. The results of this study will serve as an important reference which will benefit researchers who have interest in developing SERS methods for screening other possible veterinary drugs in meat products.

Technical Abstract: Ractopamine, frequently misused to promote lean meat production, raises significant food safety issues. This study introduces a rapid detection approach for ractopamine in pork using size-tunable Au@Ag NPs core-shell nanoparticles as surface-enhanced Raman scatting (SERS) substrates. By changing the diameter of the gold core and the thickness of the silver shell, the effects of them on the SERS enhancement of ractopamine signals were carefully studied. Interestingly, with the increase of the silver shell thickness, the SERS intensity exhibited a pattern of initially increasing, then decreasing, followed by another increase and subsequent decrease. In contrast, the gold core enlargement displayed a simpler trend: the SERS intensity first rose and then diminished. These phenomena reveal the relationship between SERS signal enhancement effect of ractopamine and local surface plasmon resonance (LSPR) and the contact area between ractopamine molecule and substrate. The most effective SERS enhancement was identified using Au@Ag NPs nanoparticles having a 32 nm Au core coupled with an 18 nm Ag shell. Further quantitative analysis showed the impressive regression correlation coefficient (R2) of 0.99, root mean square error (RMSE) of prediction at 0.012 µg/g, and the limit of detection (LOD) of 19 ng/g for ractopamine detection model spanning concentrations from 0.1 to 10 µg/g.