Polyethylenimine-interlayered silver-shell magnetic-core microspheres as multifunctional SERS substrates

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 3; no. 33; pp. 8684 - 8693
• Main Authors: Wang, Chongwen, Xu, Jiawen, Wang, Junfeng, Rong, Zhen, Li, Ping, Xiao, Rui, Wang, Shengqi
• Format: Journal Article
• Language: English
• Published: 01.01.2015
• Subjects: Agglomeration; Hot spots; Human; Interlayers; Magnetic cores; Microspheres; Noble metals; Silver
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/C5TC01839K

The fabrication of an ideal noble metal modified magnetic microsphere as a high performance SERS substrate that possesses good dispersibility, strong magnetic responsiveness, and high sensitivity is still a challenge. Herein, we report a novel route for fabricating Ag-coated magnetic core–shell microspheres (Fe 3 O 4 @PEI@Ag) with most of the desired advantages by using polyethyleneimine (PEI) as an interlayer. The size and coverage level of the Ag-NPs shell on Fe 3 O 4 @PEI@Ag microspheres were easily controlled by varying the amount of AgNO 3 . Meanwhile, the magnetic core endowed the Fe 3 O 4 @PEI@Ag microspheres with superior magnetic nature, which enabled convenient separation and further enhanced Raman signals due to enrichment of targeted analytes and abundant interparticle hotspots created by magnetism-induced aggregation. Considering these features, Fe 3 O 4 @PEI@Ag is expected to be a versatile SERS substrate, which was verified by the detection of adsorbed PATP molecules and human IgG with a detection limit as low as 10 −11 M and 10 −14 g mL −1 , respectively. Therefore, the novel Fe 3 O 4 @PEI@Ag microsphere has an enormous potential for practical SERS detection applications, especially in the field of quantitative detection of target proteins.