Detection of DNA bases and environmentally relevant biomolecules and monitoring ssDNA hybridization by noble metal nanoparticles decorated graphene nanosheets as ultrasensitive G‐SERS platforms. (22nd March 2021)

• Record Type: Journal Article
• Authors: Gupta, Sanju; Banaszak, Alexander
• Is Part Of: Journal of Raman spectroscopy. Volume 52:Number 5(2021)
• Page Start: 930
• Page End: 948
• Publication Date: 2021-03-22
• Subjects: biological molecules -- DNA hybridization -- graphene -- metal nanoparticles -- SERS; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.6087
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract: Surface‐enhanced Raman scattering (SERS) and graphene‐mediated surface‐enhanced Raman scattering (G‐SERS) are attractive analytical techniques for the detection of chemical and biological molecules at a single‐molecule level registering their chemical fingerprints. Graphene‐based surface enhancement (or G‐SERS) boosted traditional SERS phenomenon producing signal enhancement from both electromagnetic (EM) and chemical enhancement (CE) mechanisms. Thus, graphene oxide (GO) nanosheets coated with silver (Ag [30 nm]) and gold (Au [40 nm]) nanoparticles smart array platforms, for direct detection and differentiation of DNA bases, namely, adenine (A), cytosine (C), guanine (G), thymine (T), and environmental relevant β‐carotene (β‐C) and malachite green (MG) biomolecules, are developed. The size and interparticle gap were controlled via dispersion and loading on GO surface to achieve optimal enhancement factors. The morphology of these substrates was characterized by scanning electron microscopy and atomic force microscopy. The Raman spectra consisted of discrete bands occurring at (A: 732.8 cm −1 ; C: 792 cm −1 ; G: 658 cm −1 ; T: 796 cm −1 ; β‐C: 1416 cm −1 ; MG: 1174 cm −1 ) that are characteristic of molecular modes of vibration and serve as chemical fingerprint of three‐dimensional structure, intramolecular interaction and steady‐state dynamics, of biomolecule ensemble. The GO‐decorated nanoparticles are capable of sensitive biomolecular detection over a broad concentration range 100 nM to 100 μM with limit of detection (LOD) noted at <1 ppm for A, C, G, T, β‐C, and MG. Moreover, the experimental results illustrated five to six orders of magnitude signal enhancement in the following order: GO/Ag30 > GO/Au40 > Ag30 > Au40 > GO. Moreover, ssDNA probe and complementary target C‐ssDNA were monitored simultaneously during hybridization on the same substrates assigned confidently to base, local chemical structure, and global conformation of resulting dsDNA. The experimental findings suggest a strong GO‐nanoparticle coupling leading to interfacial orbital hybridization (charge transfer) and polarization affected by biomolecule orientation, and it will help in designing ultrasensitive platforms covering range of inorganic nanoparticles and nanostructured surfaces for a wealth of biomedicine and environmental applications. Abstract : The nanoarray platforms consisting of graphene‐mediated surface‐enhanced Raman scattering (G‐SERS) with noble metal (i.e., silver and gold) nanoparticles for detection of biological and chemical molecules showed optimal size nanoparticles on graphene oxide are sensitive for DNA base differentiation with limit of detection <1 pM with EM and CE enhancement mechanisms. We also used these platforms for monitoring ssDNA hybridization from complementary ssDNA.