scholarly journals Charge-Transfer Resonance and Electromagnetic Enhancement Synergistically Enabling MXenes with Excellent SERS Sensitivity for SARS-CoV-2 S Protein Detection

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yusi Peng ◽  
Chenglong Lin ◽  
Li Long ◽  
Tanemura Masaki ◽  
Mao Tang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Protein Detection ◽  
Resonance Excitation ◽  
Excitation Wavelength ◽  
Potential Candidate ◽  
Practical Applications ◽  
Electromagnetic Enhancement ◽  
Resonance Enhancement ◽  
Sers Detection ◽  
Novel Coronavirus

AbstractThe outbreak of coronavirus disease 2019 has seriously threatened human health. Rapidly and sensitively detecting SARS-CoV-2 viruses can help control the spread of viruses. However, it is an arduous challenge to apply semiconductor-based substrates for virus SERS detection due to their poor sensitivity. Therefore, it is worthwhile to search novel semiconductor-based substrates with excellent SERS sensitivity. Herein we report, for the first time, Nb2C and Ta2C MXenes exhibit a remarkable SERS enhancement, which is synergistically enabled by the charge transfer resonance enhancement and electromagnetic enhancement. Their SERS sensitivity is optimized to 3.0 × 106 and 1.4 × 106 under the optimal resonance excitation wavelength of 532 nm. Additionally, remarkable SERS sensitivity endows Ta2C MXenes with capability to sensitively detect and accurately identify the SARS-CoV-2 spike protein. Moreover, its detection limit is as low as 5 × 10−9 M, which is beneficial to achieve real-time monitoring and early warning of novel coronavirus. This research not only provides helpful theoretical guidance for exploring other novel SERS-active semiconductor-based materials but also provides a potential candidate for the practical applications of SERS technology.

scholarly journals Plasmon-coupled Charge Transfer in FSZA Core-shell Microspheres with High SERS Activity and Pesticide Detection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Donglai Han ◽  
Jiacheng Yao ◽  
Yingnan Quan ◽  
Ming Gao ◽  
Jinghai Yang
Keyword(s):  
Magnetic Field ◽  
Charge Transfer ◽  
Core Shell ◽  
Sers Substrate ◽  
Practical Application ◽  
Actual Application ◽  
Electromagnetic Enhancement ◽  
Sers Detection ◽  
Magnetite Particles ◽  
The Stability

Abstract A commercial SERS substrate does not only require strong enhancement, but also can be reused and recycled in actual application. Herein, Fe3O4/SiO2/ZnO/Ag (FSZA) have been synthesised, which consisted of Fe3O4 core with strong magnetic field response and an intermediate SiO2 layer as an electronic barrier to keep the stability of magnetite particles and outer ZnO and Ag as the effective layers for detecting pollutants. The SERS enhancement factor (EF) of the FSZA was ~8.2 × 105. The enhancement mechanism of the FSZA core-shell microspheres were anatomized. The electromagnetic enhancement of surface deposited Ag, charge transfer, and molecular and exciton resonances act together to cause such high enhancement factors. For practical application, the FSZA core-shell microspheres were also used to detect thiram, moreover, which was collected and separated by an external magnetic field, and maintained the SERS activity without significant decline during multiple tests. So the good enhancement performance and magnetic recyclability make the FSZA core-shell microspheres a promising candidates for practical SERS detection applications.

Plasmonic MoO3−x@MoO3 nanosheets for highly sensitive SERS detection through nanoshell-isolated electromagnetic enhancement

2016 ◽  
Vol 52 (14) ◽  
pp. 2893-2896 ◽  
Author(s):  
Xianjun Tan ◽  
Lingzhi Wang ◽  
Chen Cheng ◽  
Xuefeng Yan ◽  
Bin Shen ◽  
...  
Keyword(s):  
Electromagnetic Enhancement ◽  
Highly Sensitive ◽  
Sers Detection

Nanoshell-isolated electromagnetic enhancing for highly sensitive sers detection.

scholarly journals Insights into Cross-species Evolution of Novel Human Coronavirus 2019-nCoV and Defining Immune Determinants for Vaccine Development

2020 ◽  
Author(s):  
Arunachalam Ramaiah ◽  
Vaithilingaraja Arumugaswami
Keyword(s):  
Binding Affinity ◽  
Vaccine Development ◽  
Asia Pacific ◽  
Potential Candidate ◽  
T Cell Epitopes ◽  
Live Animal ◽  
Synonymous Mutations ◽  
Wide Range ◽  
Novel Coronavirus ◽  
N Proteins

ABSTRACTNovel Coronavirus (nCoV) outbreak in the city of Wuhan, China during December 2019, has now spread to various countries across the globe triggering a heightened containment effort. This human pathogen is a member of betacoronavirus genus carrying 30 kilobase of single positive-sense RNA genome. Understanding the evolution, zoonotic transmission, and source of this novel virus would help accelerating containment and prevention efforts. The present study reported detailed analysis of 2019-nCoV genome evolution and potential candidate peptides for vaccine development. This nCoV genotype might have been evolved from a bat-CoV by accumulating non-synonymous mutations, indels, and recombination events. Structural proteins Spike (S), and Membrane (M) had extensive mutational changes, whereas Envelope (E) and Nucleocapsid (N) proteins were very conserved suggesting differential selection pressures exerted on 2019-nCoV during evolution. Interestingly, 2019-nCoV Spike protein contains a 39 nucleotide sequence insertion relative to SARS-like bat-SL-CoVZC45/2017. Furthermore, we identified eight high binding affinity (HBA) CD4 T-cell epitopes in the S, E, M and N proteins, which can be commonly recognized by HLA-DR alleles of Asia and Asia-Pacific Region population. These immunodominant epitopes can be incorporated in universal subunit CoV vaccine. Diverse HLA types and variations in the epitope binding affinity may contribute to the wide range of immunopathological outcomes of circulating virus in humans. Our findings emphasize the requirement for continuous surveillance of CoV strains in live animal markets to better understand the viral adaptation to human host and to develop practical solutions to prevent the emergence of novel pathogenic CoV strains.

scholarly journals Effect of Heterointerface on NO2 Sensing Properties of In-Situ Formed TiO2 QDs-Decorated NiO Nanosheets

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1628 ◽  
Author(s):  
Congyi Wu ◽  
Jian Zhang ◽  
Xiaoxia Wang ◽  
Changsheng Xie ◽  
Songxin Shi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Gas Sensing ◽  
Tio2 Particle ◽  
Sensing Properties ◽  
Practical Applications ◽  
Enhanced Sensitivity ◽  
Peak Fitting ◽  
Two Phases ◽  
Nio Nanosheets

In this work, TiO2 QDs-modified NiO nanosheets were employed to improve the room temperature NO2 sensing properties of NiO. The gas sensing studies showed that the response of nanocomposites with the optimal ratio to 60 ppm NO2 was nearly 10 times larger than that of bare NiO, exhibiting a potential application in gas sensing. Considering the commonly reported immature mechanism that the effective charge transfer between two phases contributes to an enhanced sensitivity, the QDs sensitization mechanism was further detailed by designing a series of contrast experiments. First, the important role of the QDs size effect was revealed by comparing the little enhanced sensitivity of TiO2 particle-modified NiO with the largely enhanced sensitivity of TiO2 QDs-NiO. Second, and more importantly, direct evidence of the heterointerface charge transfer efficiency was detailed by the extracted interface bond (Ti-O-Ni) using XPS peak fitting. This work can thus provide guidelines to design more QDs-modified nanocomposites with higher sensitivity for practical applications.

scholarly journals Application of Aluminum Hydroxide for Improvement of Label-Free SERS Detection of Some Cephalosporin Antibiotics in Urine

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 91 ◽  
Author(s):  
Natalia E. Markina ◽  
Alexey V. Markin
Keyword(s):  
Aluminum Hydroxide ◽  
Surface Enhanced Raman Spectroscopy ◽  
Negative Influence ◽  
Quantitative Detection ◽  
Therapeutic Drug ◽  
Excitation Wavelength ◽  
Sers Substrate ◽  
Label Free ◽  
Surface Enhanced Raman ◽  
Sers Detection

This report is dedicated to development of surface-enhanced Raman spectroscopy (SERS) based analysis protocol for detection of antibiotics in urine. The key step of the protocol is the pretreatment of urine before the detection to minimize background signal. The pretreatment includes extraction of intrinsic urine components using aluminum hydroxide gel (AHG) and further pH adjusting of the purified sample. The protocol was tested by detection of a single antibiotic in artificially spiked samples of real urine. Five antibiotics of cephalosporin class (cefazolin, cefoperazone, cefotaxime, ceftriaxone, and cefuroxime) were used for testing. SERS measurements were performed using a portable Raman spectrometer with 638 nm excitation wavelength and silver nanoparticles as SERS substrate. The calibration curves of four antibiotics (cefuroxime is the exception) cover the concentrations required for detection in patient’s urine during therapy (25/100‒500 μg/mL). Random error of the analysis (RSD < 20%) and limits of quantification (20‒90 μg/mL) for these antibiotics demonstrate the applicability of the protocol for reliable quantitative detection during therapeutic drug monitoring. The detection of cefuroxime using the protocol is not sensitive enough, allowing only for qualitative detection. Additionally, time stability and batch-to-batch reproducibility of AHG were studied and negative influence of the pretreatment protocol and its limitations were estimated and discussed.

Excitation Wavelength Dependent Luminescence of LuNbO4:Pr3+—Influences of Intervalence Charge Transfer and Host Sensitization

2016 ◽  
Vol 120 (45) ◽  
pp. 26044-26053 ◽  
Author(s):  
Chunmeng Liu ◽  
Fengjuan Pan ◽  
Qi Peng ◽  
Weijie Zhou ◽  
Rui Shi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excitation Wavelength ◽  
Intervalence Charge Transfer

scholarly journals Simple Ion Transfer at Liquid|Liquid Interfaces

2012 ◽  
Vol 2012 ◽  
pp. 1-34 ◽  
Author(s):  
L. J. Sanchez Vallejo ◽  
J. M. Ovejero ◽  
R. A. Fernández ◽  
S. A. Dassie
Keyword(s):  
Charge Transfer ◽  
Numerical Simulations ◽  
Phase Transfer ◽  
Electrolyte Solutions ◽  
Ion Transfer ◽  
Liquid Interfaces ◽  
Practical Applications ◽  
Theoretical Approaches ◽  
Charge Transfer Reactions

The main aspects related to the charge transfer reactions occurring at the interface between two immiscible electrolyte solutions (ITIES) are described. The particular topics to be discussed involve simple ion transfer. Focus is given on theoretical approaches, numerical simulations, and experimental methodologies. Concerning the theoretical procedures, different computational simulations related to simple ion transfer are reviewed. The main conclusions drawn from the most accepted models are described and analyzed in regard to their relevance for explaining different aspects of ion transfer. We describe numerical simulations implementing different approaches for solving the differential equations associated with the mass transport and charge transfer. These numerical simulations are correlated with selected experimental results; their usefulness in designing new experiments is summarized. Finally, many practical applications can be envisaged regarding the determination of physicochemical properties, electroanalysis, drug lipophilicity, and phase-transfer catalysis.

Effect of Atmosphere Temperature on Physical Properties of ZnO/Ag/ZnO on PET Films

2014 ◽  
Vol 988 ◽  
pp. 125-129 ◽  
Author(s):  
Yun Hae Kim ◽  
Jin Woo Lee ◽  
Riichi Murakami ◽  
Dong Myung Lee ◽  
Jin Cheol Ha ◽  
...  
Keyword(s):  
Band Gap ◽  
Sheet Resistance ◽  
Chemical Properties ◽  
Raw Material ◽  
Silver Layer ◽  
Visible Range ◽  
Potential Candidate ◽  
Practical Applications ◽  
Ito Film ◽  
Transparent Conducting

Transparent conductive layers on flexible substrates are important components of today’s optoelectronic technology. They are used in filters for plasma displays, low-e windows, solar cells, etc. At present, in-doped indium oxide (ITO) layers on PET substrate is the predominant transparent conducting oxide film in diverse practical applications. However, ITO is a relatively expensive material because indium is not abundant, but aluminum-doped zinc oxide (AZO) film is emerging as an alternative potential candidate to ITO thin film due to its abundance as a raw material, nontoxic nature, cost-effectiveness, easy fabrication, and good stability in plasma. They have, however, several drawbacks: they exhibit relatively high electrical resistance (sheet resistance, 20-200Ω), considerable emissivity, and significant absorption in the spectral region 1-2μm, in which transition from high transmittance to high reflectance takes place. Furthermore, these films do not block solar thermal radiation (0.7-3μm), which may cause overheating problems to devices such as electro-chromic and photovoltaic devices. On the other hand, ITO/Ag/ITO multilayer films are used to achieve high transparent conducting properties. A thin silver layer of about 10nm thickness is embedded between two ITO layers. The ITO/Ag/ITO film has very low sheet resistance, high optical transparency in the visible range, relatively lower thickness than single-layered ITO film, and better durability than single-layered silver film. In terms of ZnO, which is a wide direct band-gap semiconductor, ZnO has a band-gap energy of 3.37 eV with a binding energy as high as 60 meV at room temperature. ZnO has been applied to various domains for excellent physical and chemical properties, such as piezoelectric sensors, rheostats , gas sensors, semiconductor lasers, and transparent conductive films.

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