SERRS Detection on Silver Nanoparticles Supported on Acid-Treated Melamine-Resin Microspheres.

Chaofeng Duan,Yuqing Guo,Xiaogang Wang,Xiaohua Wang,Zhixian Hao,Lu Shen

doi:10.3390/nano11051337

Chaofeng Duan, Yuqing Guo + Show 4 more

Open Access

https://doi.org/10.3390/nano11051337

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Abstract

Melamine-resin microspheres were synthesized at a pH of 4.0 for 20 min and used as silver nanoparticle (AgNP) carriers for surface enhanced resonant Raman scattering (SERRS) detection. An acetic acid–treatment reaction was introduced into the fabrication of the final substrate. The SERRS performance of the substrate was effectively optimized by regulating excess formaldehyde and experimental parameters, such as acidity, number of treatments and reaction temperature in the acid-treatment reaction. Based on the SERRS detection, it was declared that a trace amount of oligomers with a certain degree of polymerization is necessary for the construction of SERRS hotspots. In addition, it is important to remove excess oligomers with reference to the synthetic reaction of the polymer materials, given the special role of oligomers and the wide application of polymer materials in SERRS detection.

Highlights

Nowadays, various polymer materials, such as polystyrene, polyamide, epoxy resin, phenolic resin, urea resin [1] and melamine resin [2,3], are frequently used in the fabrication of surface enhanced resonant Raman scattering (SERRS) substrates
Melamine-resin microspheres that were synthesized for 20 min were proved to be available in the fabrication of SERRS substrate, only if they were treated with an acetic acid solution before supporting silver nanoparticles
The R6G SERRS detection limit was equal to 10−13 M that was 106 times the value detected on the blank AgNPs

Summary

Introduction

Various polymer materials, such as polystyrene, polyamide, epoxy resin, phenolic resin, urea resin [1] and melamine resin [2,3], are frequently used in the fabrication of SERRS substrates. In terms of molecular structures, the SERRS technology always takes advantages of some unique characteristics of polymer materials such as biocompatibility [15,16,17,18], multidentate coordination with metal nanoparticles [19,20], and three-dimensional construction of SERRS hotspots [19,21]. These characteristics depend on the abundance of selectable functional groups, such as –CN, –OH, –NH2 and –COOH, in their molecular structure. The confusion of these functional groups confers SERRS signals with serious reproducibility challenges that are intractable and generally concerning

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