Sensitive surface enhanced Raman spectroscopy (SERS) detection of methotrexate by core-shell-satellite magnetic microspheres

Miao Chen; Wen Luo; Zhimin Zhang; Fawei Zhu; Sen Liao; Hua Yang; Xiaoqing Chen

doi:10.1016/j.talanta.2017.04.072

Sensitive surface enhanced Raman spectroscopy (SERS) detection of methotrexate by core-shell-satellite magnetic microspheres

Talanta. 2017 Aug 15:171:152-158. doi: 10.1016/j.talanta.2017.04.072. Epub 2017 May 1.

Authors

Miao Chen¹, Wen Luo¹, Zhimin Zhang¹, Fawei Zhu¹, Sen Liao¹, Hua Yang², Xiaoqing Chen³

Affiliations

¹ College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
² College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. Electronic address: hyangchem@csu.edu.cn.
³ College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China; Collaborative Innovation Center of Resource-conserving & Environment-Friendly Society and Ecological Civilization, Changsha, China. Electronic address: xqchen@csu.edu.cn.

PMID: 28551121
DOI: 10.1016/j.talanta.2017.04.072

Abstract

An effective approach for fabricating core-shell-satellite magnetic microspheres was developed to form a sub-10nm positively charged mesoporous silica (mSiO₂) interlayer, which was applied to enrich samples and create sufficient hotspots between the inner Fe₃O₄@Ag core and outer assembled gold nanoparticles (AuNPs) satellites. Based on the prepared Fe₃O₄@Ag/mSiO₂/AuNPs (FASA) as SERS substrates, a sensitive and label-free detection of methotrexate in serum was successfully realized. The positively charged mSiO₂ interlayer exhibited strong capability in enriching methotrexate through the electrostatic interaction. The intraparticle plasmonic coupling between the inner Ag shell and the outside AuNPs satellites, and magnetism-induced aggregation greatly enhanced the SERS activity of methotrexate. The diluted serum containing different concentrations of methotrexate was employed as real samples and the minimum detected concentration of methotrexate was as low as 1nM with a linear response range from 1 to 200nM. This sensitive and label-free SERS detection of methotrexate based on FASA offers great potential for practical applications in medicine and biotechnology.

Keywords: Core-shell-satellite; Magnetic microspheres; Methotrexate; Surface-enhanced Raman scattering (SERS).