Au Film–Au@Ag Core–Shell Nanoparticle Structured Surface-Enhanced Raman Spectroscopy Aptasensor for Accurate Ochratoxin A Detection

2020 ◽  
Vol 3 (4) ◽  
pp. 2385-2391 ◽  
Author(s):  
Xiaohui Jing ◽  
Lin Chang ◽  
Lixia Shi ◽  
Xiaohong Liu ◽  
Yuan Zhao ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Ochratoxin A ◽  
Surface Enhanced Raman Spectroscopy ◽  
Core Shell ◽  
Structured Surface ◽  
Au Film ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

scholarly journals Bimetallic Core–Shell Nanoparticles of Gold and Silver via Bioinspired Polydopamine Layer as Surface-Enhanced Raman Spectroscopy (SERS) Platform

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 688 ◽  
Author(s):  
Asli Yilmaz ◽  
Mehmet Yilmaz
Keyword(s):  
Raman Spectroscopy ◽  
Low Cost ◽  
Silver Ions ◽  
Surface Enhanced Raman Spectroscopy ◽  
Core Shell ◽  
Silver Deposition ◽  
Shell Nanoparticles ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Core Shell Nanoparticles

Despite numerous attempts to fabricate the core–shell nanoparticles, novel, simple, and low-cost approaches are still required to produce these efficient nanosystems. In this study, we propose the synthesis of bimetallic core–shell nanoparticles of gold (AuNP) and silver (AgNP) nanostructures via a bioinspired polydopamine (PDOP) layer and their employment as a surface-enhanced Raman spectroscopy (SERS) platform. Herein, the PDOP layer was used as an interface between nanostructures as well as stabilizing and reducing agents for the deposition of silver ions onto the AuNPs. UV-vis absorption spectra and electron microscope images confirmed the deposition of the silver ions and the formation of core–shell nanoparticles. SERS activity tests indicated that both the PDOP thickness and silver deposition time are the dominant parameters that determine the SERS performances of the proposed core–shell system. In comparison to bare AuNPs, more than three times higher SERS signal intensity was obtained with an enhancement factor of 3.5 × 105.

scholarly journals Ag@Au Core–Shell Porous Nanocages with Outstanding SERS Activity for Highly Sensitive SERS Immunoassay

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1554 ◽  
Author(s):  
Yaqi Huang ◽  
Dajie Lin ◽  
Mengting Li ◽  
Dewu Yin ◽  
Shun Wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Raman Spectroscopy ◽  
Hot Spots ◽  
Signal Amplification ◽  
Surface Enhanced Raman Spectroscopy ◽  
Core Shell ◽  
Chloroauric Acid ◽  
Highly Sensitive ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

A highly sensitive immunoassay of biomarkers has been achieved using 4-mercaptobenzoic acid-labeled Ag@Au core–shell porous nanocage tags and α-fetoprotein immuno-sensing chips. The Ag@Au porous nanocages were uniquely synthesized by using an Ag core as a self-sacrificial template and reducing agent, where the slow reaction process led to the formation of a porous Au layer. The size of the remaining Ag core and surface roughness of the Au shell were controlled by adjusting the chloroauric acid concentration. The porous cage exhibited excellent surface-enhanced Raman spectroscopy (SERS) activity, presumably due to a synergetic interaction between newly generated hot spots in the rough Au shell and the retained SERS activity of the Ag core. Using α-fetoprotein as a model analyte for immunoassay, the SERS signal had a wide linear range of 0.20 ng mL−1 to 500.0 ng mL−1 with a detection limit of 0.12 ng mL−1. Without the need of further signal amplification, the as-prepared Ag@Au bimetallic nanocages can be directly used for highly sensitive SERS assays of other biomarkers in biomedical research, diagnostics, etc.

Understanding the strain effect of Au@Pd nanocatalysts by in situ surface-enhanced Raman spectroscopy

2019 ◽  
Vol 55 (60) ◽  
pp. 8824-8827 ◽  
Author(s):  
Jie Wei ◽  
Yu-Jin Zhang ◽  
Si-Na Qin ◽  
Wei-Min Yang ◽  
Hua Zhang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Strain Effect ◽  
Core Shell ◽  
Structure Activity ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Relationship Of ◽  
Gap Mode

A gap-mode configuration was developed for the in situ SERS study of the structure–activity relationship of Au@Pd core–shell nanocatalysts, which show much better performance in the selective oxidation of benzyl alcohol compared to Pd.

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