Polyethylenimine-Capped Ag Nanoparticle Film as a Platform for Detecting Charged Dye Molecules by Surface-Enhanced Raman Scattering and Metal-Enhanced Fluorescence

Title
Polyethylenimine-Capped Ag Nanoparticle Film as a Platform for Detecting Charged Dye Molecules by Surface-Enhanced Raman Scattering and Metal-Enhanced Fluorescence
Authors
이지원Kwan KimKuan Soo Shin
Issue Date
2012-10
Publisher
ACS Applied Materials & Interfaces
Citation
VOL 4, NO 10-5504
Abstract
Many drugs are charged molecules and are weak bases or acids having counterions. Their binding to biological surfaces is generally difficult to assess by vibrational spectroscopy. In this work, we demonstrated the potential of surface-enhanced Raman scattering (SERS) conducted using a polyethylenimine (PEI)-capped Ag nanoparticle film for the quantification of an electrostatic adsorption process of charged drug molecules, by using charged dye molecules such as sulforhodamine B (SRB) and rhodamine-123 (R123) as model drugs. It was possible to detect small-sized anions such as SCN- at 1 x 10(-9) M by SERS because of the cationic property of PEI. We were subsequently able to detect a prototype anionic dye molecule, SRB, by SEAS at a subnanomolar concentration. On the other hand, it was difficult to detect cationic dyes such as R123 because of the electrostatically repulsive interaction with PEI. Nonetheless, we found that even R123 could be detected at subnanomolar concentrations by SERS by depositing an anionic polyelectrolyte such as poly(sodium 4-styrenesulfonate) (PSS) and poly(acrylic acid) (PAA) onto the PEI-capped Ag nanoparticles. Another noteworthy point is that a subnanomolar detection limit can also be achieved by carefully monitoring the fluorescence background in the measured SEAS spectra. This was possible because charged dyes were not in contact with Ag but formed ion pairs with either PEI or PSS (PAA), allowing metal-enhanced fluorescence (MEF). The PEI-capped Ag nanoparticle film can thus serve as a useful indicator to detect charged drug molecules by SERS and MEF.
URI
http://pubs.kist.re.kr/handle/201004/72630
ISSN
1944-8244
Appears in Collections:
KIST Publication > Article
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE