Sensitive Detection of Biomolecules by Surface Enhanced Raman Scattering using Plant Leaves as Natural Substrates

Abstract

Abstract. Detection of biomolecules is highly important for biomedical and other biological applications. Although several methods exist for the detection of biomolecules, surface enhanced Raman scattering (SERS) has a unique role in greatly enhancing the sensitivity. In this work, we have demonstrated the use of natural plant leaves as facile, low cost and eco-friendly SERS substrates for the sensitive detection of biomolecules. Specifically, we have investigated the influence of surface topography of five different plant leaf based substrates, deposited with Au, on the SERS performance by using L-cysteine as a model biomolecule. In addition, we have also compared the effect of sputter deposition of Au thin film with dropcast deposition of Au nanoparticles on the leaf substrates. Our results indicate that L-cysteine could be detected with high sensitivity using these plant leaf based substrates and the leaf possessing hierarchical micro/nanostructures on its surface shows higher SERS enhancement compared to a leaf having a nearplanar surface. Furthermore, leaves with drop-casted Au nanoparticle clusters performed better than the leaves sputter deposited with a thin Au film.

Charge Transfer Surface-Enhanced Raman and Absorption Spectra of the Zwitterionic Form of Cysteine Adsorbed on M@Au12 (M = Au, Ag, Pt, and Pd) Nanoclusters

“…The enhancement of the signal intensity in SERS is dependent on factors such as molecule distance, orientation, and affinity toward the metal surface. The SERS spectrum of the LC interacting with various metal surfaces has been studied both theoretically as well as experimentally. − Graff et al investigated the adsorption of the l - and d -cysteine enantiomers on an Ag electrode surface using the SERS technique as a function of electrode potential and solvent pH . A complete experimental study has been performed by Guicheteau et al on the IR, Raman, and SERS spectra of a series of amino acids (phenylalanine, tyrosine, tryptophan, glutamine, cysteine, alanine, proline, methionine, asparagine, threonine, valine, glycine, serine, leucine, isoleucine, aspartic acid, and glutamic acid) and the nucleic acid bases (adenosine, guanosine, thymidine, and uridine) .…”

“…Huang et al used an electro-plasmonic approach in which a single Au nanoparticle trapped in a nanohole generated a massive field in the nanocavity, allowing SERS discrimination of ten different amino acids at the single-molecule level . Sharma et al proposed using plant leaves as natural substrates for the SERS to detect biomolecules . Using the LC as a biomolecule model, they investigated the topology effect of five different plant leaf-based substrates deposited with Au on SERS performance.…”

“…39 Sharma et al proposed using plant leaves as natural substrates for the SERS to detect biomolecules. 40 Using the LC as a biomolecule model, they investigated the topology effect of five different plant leaf-based substrates deposited with Au on SERS performance. Malachite green was used as a probe molecule to investigate the effect of LC on the SERS activity of colloidal Ag nanoparticles.…”