scholarly journals Recyclable SERS-Based Immunoassay Guided by Photocatalytic Performance of Fe3O4@TiO2@Au Nanocomposites

Biosensors ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 25 ◽  
Author(s):  
Yuanyuan Du ◽  
Hongmei Liu ◽  
Yiran Tian ◽  
Chenjie Gu ◽  
Ziqi Zhao ◽  
...  
Keyword(s):  
Photocatalytic Performance ◽  
Limit Of Detection ◽  
Specific Antigen ◽  
High Sensitivity ◽  
Shell Nanoparticles ◽  
Sem Images ◽  
Potential Measurement ◽  
Surface Enhanced Raman ◽  
Clinical Measurements ◽  
Core Shell Nanoparticles

A novel recyclable surface-enhanced Raman scattering (SERS)-based immunoassay was demonstrated and exhibited extremely high sensitivity toward prostate specific antigen (PSA). The immunoassay, which possessed a sandwich structure, was constructed of multifunctional Fe3O4@TiO2@Au nanocomposites as immune probe and Ag-coated sandpaper as immune substrate. First, by adjusting the density of outside Au seeds on Fe3O4@TiO2 core-shell nanoparticles (NPs), the structure-dependent SERS and photocatalytic performance of the samples was explored by monitoring and degradating 4-mercaptobenzonic acid (4MBA). Afterwards, the SERS enhancement capability of Ag-coated sandpaper with different meshes was investigated, and a limit of detection (LOD), as low as 0.014 mM, was achieved by utilizing the substrate. Subsequently, the recyclable feasibility of PSA detection was approved by zeta potential measurement, absorption spectra, and SEM images and, particularly, more than 80% of SERS intensity still existed after even six cycles of immunoassay. The ultralow LOD of the recyclable immunoassay was finally calculated to be 1.871 pg/mL. Therefore, the recyclable SERS-based immunoassay exhibits good application prospects for diagnosis of cancer in clinical measurements.

scholarly journals SERS-based sandwich bioassay protocol of miRNA-21 using Au@Ag core–shell nanoparticles and a Ag/TiO2 nanowires substrate

2019 ◽  
Vol 11 (23) ◽  
pp. 2960-2968 ◽  
Author(s):  
Le Peng ◽  
Jun Zhou ◽  
Zhaoheng Liang ◽  
Yaping Zhang ◽  
Lucia Petti ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Sandwich Structure ◽  
High Sensitivity ◽  
Core Shell ◽  
Tio2 Nanowires ◽  
Shell Nanoparticles ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Core Shell Nanoparticles

Based on surface-enhanced Raman scattering (SERS) technology, Au@Ag@4MBA@5′-NH2-ssDNA probes and a Ag/TiO2@3′-NH2-ssDNA substrate were prepared and constructed into a sandwich structure to develop a high sensitivity bioassay of miRNA-21.

scholarly journals Synthesis of MBA-Encoded Silver/Silica Core-Shell Nanoparticles as Novel SERS Tags for Biosensing Gibberellin A3 Based on Au@Fe3O4 as Substrate

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5152 ◽  
Author(s):  
Qingmin Wei ◽  
Jianjuan Lin ◽  
Fa Liu ◽  
Changchun Wen ◽  
Na Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fe3o4 Nanoparticles ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Shell Nanoparticles ◽  
Gibberellin A3 ◽  
Sers Signal ◽  
Surface Enhanced Raman ◽  
The Stöber Method ◽  
Sers Tags

A surface-enhanced Raman scattering (SERS) tag is proposed for high-sensitivity detection of gibberellin A3 (GA3). Silver nanoparticles (AgNPs) were synthesized using citrate reduction. 4-Mercaptobenzoic acid (MBA) was used for the Raman-labeled molecules, which were coupled to the surface of the AgNPs using sulfydryls. MBA was coated with silica using the Stöber method to prevent leakage. GA3 antibodies were attached via the active functional groups N-Hydroxysuccinimide (NHS) and N-Ethyl-N’-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) to construct a novel immuno-AgNPs@SiO2 SERS tags. The captured SERS substrates were fabricated through Fe3O4 nanoparticles and gold nanoparticles (AuNPs) using chemical methods. These nanoparticles were characterized using ultraviolet-visible spectroscopy (UV–Vis), dynamic light scattering, Raman spectroscopy, transmission electron microscope (TEM), and X-ray diffraction (XRD). This immuno-AgNPs@SiO2 SERS tags has a strong SERS signal based on characterizations via Raman spectroscopy. Based on antigen-antibody reaction, the immuno-Au@Fe3O4 nanoparticles can capture the GA3 and AgNPs@SiO2 SERS tags. Due to the increasing number of captured nanoprobes, the SERS signal from MBA was greatly enhanced, which favored the sensitive detection of GA3. The linear equation for the SERS signal was y = −13635x + 202211 (R2 = 0.9867), and the limit of detection (LOD) was 10−10 M. The proposed SERS tags are also applicable for the detection of other food risk factors.

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 Performance Improving Method of Aligned Silver Nanorod by Grafting Au@Ag Core–Shell Nanoparticles for Surface-Enhanced Raman Scattering

NANO ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. 1750131 ◽  
Author(s):  
Jian Chen ◽  
Peitao Dong ◽  
Chaoguang Wang ◽  
Chenyu Zhang ◽  
Junfeng Wang ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Surface Enhanced Raman Scattering ◽  
Core Shell ◽  
Sers Substrate ◽  
Shell Nanoparticles ◽  
Simple Method ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Core Shell Nanoparticles

A simple method for improving surface-enhanced Raman scattering (SERS) performance of aligned silver nanorod (Ag NR) array was investigated. This method was to construct a kind of hybrid substrate by grafting Au@Ag core–shell nanoparticles (NPs) into Ag NR array using poly(2-vinylphridine) (P2VPy) as a bridging agent. The hybrid substrate yielded excellent SERS performance as its detection limit improved from 10[Formula: see text] M to 10[Formula: see text] M using trans-1,2-bis(4-pyridyl)ethylene (BPE) as probe molecule, which was increased by two orders of magnitude compared with Ag NR array substrate. The significant improvement of SERS performance of Ag NR arrays was attributed to the addition of Au@Ag core–shell NPs. As a result of surface plasmon resonance generated by the interaction of electromagnetic (EM) (IAEM) filed between NP and NR structures, increasing hotspots were found at the connections of NPs and NRs, the gaps of adjacent rods, and the gaps of two particles consequently. These results were validated by the finite difference time domain (FDTD) calculation. Besides, hybrid substrate shows good performance in stability and reproducibility. The proposed method was simple and robust, which promoted SERS performance of Ag NR array effectively, showing great potential in the application of SERS substrate fabrication and SERS-based bio-chemical sensing.

scholarly journals Rapid label-free SERS detection of foodborne pathogenic bacteria based on hafnium ditelluride-Au nanocomposites

2020 ◽  
Vol 13 (05) ◽  
pp. 2041004 ◽  
Author(s):  
Yang Li ◽  
Yanxian Guo ◽  
Binggang Ye ◽  
Zhengfei Zhuang ◽  
Peilin Lan ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Limit Of Detection ◽  
Principal Component ◽  
High Sensitivity ◽  
Chemical Mechanism ◽  
Sers Substrate ◽  
Label Free ◽  
Label Free Detection ◽  
Surface Enhanced Raman ◽  
Foodborne Pathogenic Bacteria

Two-dimensional (2D) nanomaterials have captured an increasing attention in biophotonics owing to their excellent optical features. Herein, 2D hafnium ditelluride (HfTe[Formula: see text], a new member of transition metal tellurides, is exploited to support gold nanoparticles fabricating HfTe2-Au nanocomposites. The nanohybrids can serve as novel 2D surface-enhanced Raman scattering (SERS) substrate for the label-free detection of analyte with high sensitivity and reproducibility. Chemical mechanism originated from HfTe2 nanosheets and the electromagnetic enhancement induced by the hot spots on the nanohybrids may largely contribute to the superior SERS effect of HfTe2-Au nanocomposites. Finally, HfTe2-Au nanocomposites are utilized for the label-free SERS analysis of foodborne pathogenic bacteria, which realize the rapid and ultrasensitive Raman test of Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella with the limit of detection of 10 CFU/mL and the maximum Raman enhancement factor up to [Formula: see text]. Combined with principal component analysis, HfTe2-Au-based SERS analysis also completes the bacterial classification without extra treatment.

scholarly journals Au@Ag core–shell nanoparticles with a hidden internal reference promoted quantitative solid phase microextraction-surface enhanced Raman spectroscopy detection

RSC Advances ◽  
2017 ◽  
Vol 7 (38) ◽  
pp. 23866-23874 ◽  
Author(s):  
Lei Sun ◽  
Min Zhang ◽  
Vinothkumar Natarajan ◽  
Xiaofei Yu ◽  
Xiaoli Zhang ◽  
...  
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Surface Enhanced Raman Spectroscopy ◽  
Structural Representation ◽  
Internal Reference ◽  
Shell Nanoparticles ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Detection ◽  
Core Shell Nanoparticles

Structural representation of the SPME-SERS fiber with an internal reference and the SERS detection.

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