Silver nanoparticle aggregates on copper foil for reliable quantitative SERS analysis of polycyclic aromatic hydrocarbons with a portable Raman spectrometer

2015

SPIE Proceedings

Nanometerial-based optical nanoprobes have been extensively developed because of their high sensitivity, good specificity, and potential for easy quantification of species in chemical and biological analysis. With the development of nanotechnology, various kinds of nanomaterials with novel optical properties have heen generated, laying the foundation of optical nanoprobes. By further integrating receptors (chemical ligand, aptamer, molecular imprinting polymer, etc.), the information of binding specific targets will transform into analytically optical signals by employing different detection techniques including colorimetry/UV-Vis spectra, fluorometry and surface enhanced Raman scattering (SERS). In this presentation, firstly, we introduced a simple, rapid and ultrasensitive SERS nanosensor for mercury ion (Hg 2+ ) detection based on the 4-mercaptopyridine (4-MPY) functionalized silver nanoparticles (AgNPs) in the presence of spermine; then, a novel colorimetric nanosensor for mercury species was developed for the first time due to the analyteinduced aggregation of gold nanoparticles (AuNPs) with the assistance of a thiol-containing ligand of diethyldithiocarbamate (DDTC); finally, the sensitive and selective recognition and detection of trypsin was realized in a SERS strategy by using anti-aggregation of 4-MPY-functionalized AgNPs on the basis of the interaction between protamine and trypsin.

Section: Introductionmentioning

confidence: 99%

Nanomaterial-based optical sensors for sensitive detection of heavy metal ions

Wang

2015

SPIE Proceedings

“…21 Up to now, various AgNPs-based SERS applications have been reported. 16,[21][22][23][24] For example, Ren et al have reported the determination of mercury ions by a direct SERS technique based on the interaction between AgNPs and mercury ions. 21 Jiang et al have developed a AgNPs aggregates-based SERS substrate for sensitive detection of polycyclic aromatic hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Ultrasensitive surface-enhanced Raman scattering detection of trypsin based on anti-aggregation of 4-mercaptopyridine-functionalized silver nanoparticles: an optical sensing platform toward proteases

2013

Nanoscale

In this work, a simple and sensitive surface-enhanced Raman scattering (SERS) strategy was developed for recognition and detection of trypsin, by using anti-aggregation of 4-mercaptopyridine (4-MPY)-functionalized silver nanoparticles (AgNPs) based on the interaction between protamine and trypsin.The polycationic protamine not only served as a substrate for enzyme hydrolysis but also worked as a medium for SERS enhancement, which could bind negatively charged 4-MPY-functionalized AgNPs and induce their aggregation. The hydrolysis catalyzed with trypsin in sample solution decreased the concentration of free protamine, resulting in the dispersion of AgNPs and thus decreasing the Raman intensity of 4-MPY, by which the trypsin could be sensed optically. A detection level down to 0.1 ng mL À1 for trypsin was obtained. The induced accumulation of AgNPs modified with Raman reporter 4-MPY largely enhanced the SERS responses. A good linearity was found within the wide range over five orders of magnitude and reasonable relative standard deviations (between 2.4 and 11.6%) were attained. By using trypsin as a model, the new concept can provide an excellent platform for ultrasensitive SERS measurements of various proteases/enzymes which can lead to nanoparticles stability change through catalyzed hydrolysis toward substrate.

“…The experiment is based on the reduction of AgNO 3 by copper foil in aqueous medium. This method is relatively simple and no complicated equipment or special reagents needed [5]. However, the reaction rate of copper foil reacted with silver nitrate is too fast and the deposition of the Ag nanoparticles is not easy to control, which results in the morphology of the Ag nanoparticles prepared by this method is irregular and nonuniform [6].…”

Section: Introductionmentioning

confidence: 99%

Silver nanoparticles aggregate on passivated copper foil for Surface-enhanced Raman scattering

Zhang

The 8th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems

et al. 2013

Surface-enhanced Raman scattering (SERS), as a powerful tool of chemical and biological analysis, has been investigated extensively in recent years. In this work, the reduction of silver nitrate by copper foil in aqueous medium was used to prepare silver nanoparticles and a method of applying ultrasonic to passivate the copper foil in the sulfuric acid solution was proposed in order to regulate the deposition of the Ag nanoparticles. Analysis of the surface structure by a fieldemission scanning electron microscope (FESEM) revealed that the silver nanoparticles deposited on the passivated copper foil were more regular. SERS spectra of Rhodamine6G (R6G) adsorbed on these Ag-Cu substrates were studied and compared. It's found that the Ag-Cu substrate prepared with the Cu foil passivated by ultrasonic treatment has a significantly higher Raman signal sensitivity, better large-area uniformity, and 80% of original sensitivity was remained in 10 days of storage time in the air, indicating the substrates are fairly stable.