5 February 2011 Manipulation of silver nanoparticles in a droplet for label-free detection of biological molecules using surface-enhanced Raman scattering
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Proceedings Volume 7911, Plasmonics in Biology and Medicine VIII; 791102 (2011); doi: 10.1117/12.871219
Event: SPIE BiOS, 2011, San Francisco, California, United States
Abstract
Detection and identification of biomacromolecules is of critical importance in many fields ranging from biotechnology to medicine. Surface-enhanced Raman scattering (SERS) is an emerging technique for the label-free detection and identification of biological molecules and structures with its fingerprinting properties and high sensitivity. However, there are a number of obstacles for its applications for biological macromolecules due to their complexity. In this report, manipulation of microscopic processes in play during the drying of a sessile droplet as a tool to influence the nanoparticle-macromolecule packing, which has dramatic effect on SERS performance, before the SERS acquisition is demonstrated. A process known as the coffee ring phenomenon jams all particles and molecular species to the edges of the droplet during drying. This uncontrolled process has dramatic effects on a SERS experiment, using colloidal metal nanoparticles as substrates, by sweeping everything to the edges and influencing the packing of nanoparticles in the droplet area. A plastic tip was dipped into a drying sample droplet to influence the uncontrolled piling up. A negatively-charged protein, BSA, a positively-charged protein, cytochrom c, and a 20-base long oligonucleotide, were used as model biomacromolecules in this study. While a minimum of one order of magnitude lower concentration improvement in detection limit was observed with negatively-charged biomacromolecules, no significant improvement was observed with positively-charged ones compared to a sample droplet left on the surface without any interference. With the demonstrated approach, picomolar-level biomolecular detection using SERS is possible.
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Mustafa Çulha, Mine Altunbek, Sercan Keskin, Deniz Saatçi, "Manipulation of silver nanoparticles in a droplet for label-free detection of biological molecules using surface-enhanced Raman scattering", Proc. SPIE 7911, Plasmonics in Biology and Medicine VIII, 791102 (5 February 2011); doi: 10.1117/12.871219; https://doi.org/10.1117/12.871219
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KEYWORDS
Proteins

Molecules

Nanoparticles

Raman spectroscopy

Metals

Molecular biology

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