Stable SERS substrate based on highly reflective metal liquid-like films wrapped hydrogels for direct determination of small molecules in a high protein matrix

• Published in: Talanta (Oxford) Vol. 234; p. 122678
• Main Authors: Huo, Chengcheng, Han, Wanying, Tang, Wei, Duan, Xinrui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2021
• Subjects: Drug-protein interaction; Hydrogels; Metal liquid-like films; SERS; Drug-protein interaction; Hydrogels; SERS; Metal liquid-like films
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2021.122678

The study of the interaction between small molecules and proteins is important. Surface-enhanced Raman spectroscopy (SERS) is suitable for such applications since it has the power of detecting a molecule based on its intrinsic nature and without labeling. Herein, the MeLLFs@PAAG SERS substrate supporting highly reflective metal liquid-like films (MeLLFs) with polyacrylamide hydrogels (PAAG) has high-density “hot spots” to provide excellent SERS activity. The MeLLFs@PAAG formed by AgNPs only has less than 15% SERS activity loss when stored in the air for more than three weeks. By using rhodamine 6G (R6G) as a model analyte, the AgNPs based MeLLFs@PAAG SERS substrate exhibits an enhancement factor (EF) as high as 8.0 × 106, a limit of detection (LOD) of 76.8 pM (S/N = 3). Also, the formed PAAG provided a 3D molecular network to orderly secure the assembled nanoparticles (NPs), which not only improves the stability of NPs but also shields the Raman signal of proteins as high as 45 g/L allowing the direct determination of the binding rate of human serum albumin (HSA) and doxorubicin (DOX). A binding rate of about 70% was detected, which is consistent with previous reports. Thus, proposed the MeLLFs@PAAG SERS substrate can be used as a promising candidate for SERS measurement in complex biological samples. [Display omitted] •Facile synthesis of Biocompatible SERS substrate based on highly reflective metal liquid-like films.•Hydrogel protects the metal nanoparticles away oxidization in air ensures long term storage.•Hydrogel shields the Raman signal of proteins allowing direct determination of small molecule in a high protein matrix.•Direct determination of free concentration of DOX within large amount of HSA in solution.