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https://www.readbyqxmd.com/read/28212025/advances-in-tip-enhanced-near-field-raman-microscopy-using-nanoantennas
#1
Xian Shi, Nicolás Coca-López, Julia Janik, Achim Hartschuh
Tip-enhanced near-field Raman microscopy spectroscopy is a scanning probe technique that is capable of providing vibrational spectroscopic information on single nanoobjects and surfaces at (sub-) nanometer spatial resolution and high detection sensitivity. In this review, we first illustrate the physical principle of optical nanoantennas used in tip-enhanced near-field Raman microscopy and tip-enhanced Raman scattering (TERS) to efficiently couple light to Raman excitations on nanometer length scales. Although the antennas' electric near-field distributions are commonly understood to determine the spatial resolution, recent experiments showing subnanometer-resolved optical images put this understanding into question...
February 17, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28212020/a-new-reaction-pathway-induced-by-plasmon-for-selective-benzyl-alcohol-oxidation-on-biocl-possessing-oxygen-vacancies
#2
Hao Li, Feng Qin, Zhiping Yang, Ximin Cui, Jianfang Wang, Lizhi Zhang
Selective organic transformation under mild conditions constitutes a challenge in green chemistry, especially for alcohol oxidation, which typically requires environmentally unfriendly oxidants. Here, we report a new plasmonic catalyst of Au supported on BiOCl containing oxygen vacancies. It photocatalyzes selective benzyl alcohol oxidation with O2 under visible light through synergistic action of plasmonic hot electrons and holes. Oxygen vacancies on BiOCl facilitate the trapping and transfer of plasmonic hot electrons to adsorbed O2, producing •O2(‒) radicals, while plasmonic hot holes remaining on the Au surface mildly oxidize benzyl alcohol to corresponding carbon-centered radicals...
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28211363/nanowire-networks-and-hollow-nanospheres-of-ag-au-bimetallic-alloys-at-room-temperature
#3
R Britto Hurtado, M Cortez-Valadez, H Arizpe-Chávez, N S Flores-Lopez, Ramón A B Álvarez, M Flores-Acosta
Due to their physicochemical properties, metallic nanoalloys have potential applications in biomedicine, electrocatalysis and electrochemical sensors, among many other fields. New alternative procedures have emerged in order to reduce production costs and the use of toxic substances. In this study we present a novel low-toxicity synthesis method for the fabrication of nanowire networks (NWNs) and Ag-Au hollow nanospheres. The synthesis process is performed at room temperature without any sophisticated equipment, such as special cameras or furnaces, etc...
March 17, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28211084/endothelial-cells-biophysical-biochemical-and-chromosomal-aberrancies-in-high-glucose-condition-within-the-diabetic-range
#4
Aysa Rezabakhsh, Elahe Nabat, Mina Yousefi, Soheila Montazersaheb, Omid Cheraghi, Amir Mehdizadeh, Farzaneh Fathi, Ali Akbar Movassaghpour, Nasrin Maleki-Dizaji, Reza Rahbarghazi, Alireza Garjani
To date, many studies have been conducted to find out the underlying mechanisms of hyperglycemia-induced complications in diabetes mellitus, attributed to the cellular pathologies of different cells-especially endothelial cells. However, there are still many ambiguities and unresolved issues to be clarified. Here, we investigated the alteration in biophysical and biochemical properties in human umbilical vein endothelial cells exposed to a high-glucose concentration (30mM), comparable to glucose content in type 2 diabetes mellitus, over a course of 120 hours...
February 17, 2017: Cell Biochemistry and Function
https://www.readbyqxmd.com/read/28209997/antisense-mir-132-blockade-via-the-ache-r-splice-variant-mitigates-cortical-inflammation
#5
Nibha Mishra, Lyndon Friedson, Geula Hanin, Uriya Bekenstein, Meshi Volovich, Estelle R Bennett, David S Greenberg, Hermona Soreq
MicroRNA (miR)-132 brain-to-body messages suppress inflammation by targeting acetylcholinesterase (AChE), but the target specificity of 3'-AChE splice variants and the signaling pathways involved remain unknown. Using surface plasmon resonance (SPR), we identified preferential miR-132 targeting of soluble AChE-R over synaptic-bound AChE-S, potentiating miR-132-mediated brain and body cholinergic suppression of pro-inflammatory cytokines. Inversely, bacterial lipopolysaccharide (LPS) reduced multiple miR-132 targets, suppressed AChE-S more than AChE-R and elevated inflammatory hallmarks...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28209032/surface-plasmon-resonance-investigations-of-bioselective-element-based-on-the-recombinant-protein-a-for-immunoglobulin-detection
#6
A Bakhmachuk, O Gorbatiuk, A Rachkov, B Dons'koi, R Khristosenko, I Ushenin, V Peshkova, A Soldatkin
The developed surface plasmon resonance (SPR) biosensor based on the recombinant Staphylococcal protein A with an additional cysteine residue (SPA-Cys) used as a biorecognition component showed a good selectivity and sensitivity for the immunoglobulin detection. The developed biosensor with SPA-Cys-based bioselective element can also be used as a first step of immunosensor creation. The successful immobilization of SPA-Cys on the nanolayer gold sensor surface of the SPR spectrometer was performed. The efficiency of blocking nonspecific sorption sites on the sensor surface with milk proteins, gelatin, BSA, and HSA was studied, and a rather high efficiency of using gelatin was confirmed...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28208308/ultrasensitive-surface-enhanced-raman-scattering-sensor-of-gaseous-aldehydes-as-biomarkers-of-lung-cancer-on-dendritic-ag-nanocrystals
#7
Zhen Zhang, Wei Yu, Jing Wang, Dan Luo, Xuezhi Qiao, Xiaoyun Qin, Tie Wang
Surface-enhanced Raman scattering (SERS) is expected as a technique that even theoretically detected chemicals at the single molecule level by surface plasmon phenomena of noble metal nanostructures. Insensitivity of detecting Raman weak-intensity molecules and low adsorptivity of gaseous molecules on solid substrates are two main factors hindering the application of SERS in gas detectors. In this manuscript, we demonstrated an operational SERS strategy to detect gaseous Raman weak-intensity aldehydes that have been considered as a biomarker of lung cancer for abnormal content was measured in volatile organic compounds (VOCs) of lung cancer patients...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208297/label-free-lspr-detection-of-trace-lead-ii-ions-in-drinking-water-by-synthetic-poly-mpd-co-asa-nanoparticles-on-gold-nanoislands
#8
Guangyu Qiu, Siu Pang Ng, Xiongyi Liang, Ning Ding, Xiangfeng Chen, Chi-Man Lawrence Wu
Using self-assembly gold nanoislands (SAM-AuNIs) functionalized by poly(m-phenylenediamine-co-aniline-2-sulfonic acid) (poly(mPD-co-ASA)) copolymer nanoparticles as specific receptors, a highly sensitive localized surface plasmon resonance (LSPR) optochemical sensor is demonstrated for detection of trace lead cation (Pb(II)) in drinking water. The copolymer receptor is optimized in three aspects: (1) mole ratio of mPD:ASA monomers, (2) size of copolymer nanoparticles, and (3) surface density of the copolymer...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208290/biochip-spray-simplified-coupling-of-surface-plasmon-resonance-biosensing-and-mass-spectrometry
#9
Sweccha Joshi, Han Zuilhof, Teris A van Beek, Michel W F Nielen
A simplified coupling of surface plasmon resonance (SPR) immuno-biosensing with ambient ionization mass spectrometry (MS) was developed. It combines two orthogonal analysis techniques: the biosensing capability of SPR and the chemical identification power of high resolution MS. As a proof-of-principle, deoxynivalenol (DON), an important mycotoxin, was captured using an SPR gold chip containing an antifouling layer and monoclonal antibodies against the toxin and, after washing, the chip could be taken out and analyzed by direct spray MS of the biosensor chip to confirm the identity of DON...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208287/highly-uniform-gold-nanobipyramids-for-ultrasensitive-colorimetric-detection-of-influenza-virus
#10
Shaohua Xu, Wenjun Ouyang, Peisi Xie, Yi Lin, Bin Qiu, Zhenyu Lin, Guonan Chen, Longhua Guo
Gold nanoparticles (AuNPs) have been frequently utilized for the construction of diverse colorimetric biosensors. Normally, AuNPs with sharp edges could have better sensitivity. However, the poor monodipersity of AuNPs with sharp edges seriously confines their utility for colorimetric biosensing. Herein, we demonstrate the utility of highly uniform gold nanobipyramids (Au NBPs) for ultrasensitive colorimetric detection of H5N1 virus. The proposed method is based on the fact that alkaline phosphatase (ALP) could catalyze the decomposition of 4-aminophenyl phosphate (4-APP) to generate 4-aminophenol (4-AP), which would then reduce silver nitrate to metal silver and then deposited on Au NBPs...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208282/general-sensitive-detecting-strategy-of-ions-through-plasmonic-resonance-energy-transfer-from-gold-nanoparticles-to-rhodamine-spirolactam
#11
Ming Xuan Gao, Hong Yan Zou, Yuan Fang Li, Cheng Zhi Huang
Plasmonic resonance energy transfer (PRET), which occurs between the plasmonic nanoparticles and organic dyes, has significant potential in target sensing chemistry owing to its sensitivity at the single nanoparticle level. In this contribution, by using AuNPs, which has localized surface plasmonic resonance light scattering (LSPR-LS) around 550 nm, as the donor of PRET, a general sensitive detecting strategy of ions were developed. Targets can specifically react with a ring-close structured rhodamine spirolactam, which was prepared from rhodamines in the presence of different primary amine wherein the option of the primary amine is up to the targets, forming ring-open structured rhodamine spirolactam with the strong absorption around 550 nm...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208262/prussian-blue-as-a-highly-sensitive-and-background-free-resonant-raman-reporter
#12
Yongmei Yin, Qiang Li, Sisi Ma, Huiqiao Liu, Bo Dong, Jie Yang, Dingbin Liu
We report a surprising discovery that Prussian blue (PB) can be employed as a highly sensitive and background-free resonant Raman reporter. Conventional Raman reporters show multiple spectral bands in the fingerprint region, which are generally overlapped with those from dominant endogenous biomolecules, and are thus difficult to be separated. Herein, we found that PB only possesses a strong and sharp single-band in the cellular Raman-silent region, where no Raman signals from biological species were observed...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28208255/effect-of-probe-probe-distance-on-the-stability-of-dna-hybrids-on-surfaces
#13
Lucyano J A Macedo, Erin N Miller, Aric Opdahl
We have used temperature gradient surface plasmon resonance (SPR) measurements to quantitatively evaluate how the stability of different types of hybrids formed with DNA probes on surfaces is affected by probe spacing. SPR sensors with different average surface densities of probes were prepared by coadsorbing probes with lateral spacers strands comprised of phosphorothioated adenine nucleotides (A15*). Increasing the fraction of A15* spacers in the immobilization solution results in larger distances between probes on the sensor, determined here using a combination of SPR and X-ray photoelectron spectroscopy (XPS) measurements...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28207776/the-improved-efficacy-of-sifuvirtide-compared-with-enfuvirtide-might-be-related-to-its-selectivity-for-the-rigid-biomembrane-as-determined-through-surface-plasmon-resonance
#14
Ping Cao, Guifang Dou, Yuanguo Cheng, Jinjing Che
Most mechanistic studies on human immunodeficiency virus (HIV) peptide fusion inhibitors have focused on the interactions between fusion inhibitors and viral envelope proteins. However, the interactions of fusion inhibitors with viral membranes are also essential for the efficacy of these drugs. Here, we utilized surface plasmon resonance (SPR) technology to study the interactions between the HIV fusion inhibitor peptides sifuvirtide and enfuvirtide and biomembrane models. Sifuvirtide presented selectivity toward biomembrane models composed of saturated dipalmitoylphosphatidylcholine (DPPC) (32-fold higher compared with unsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine [POPC]) and sphingomyelin (SM) (31-fold higher compared with POPC), which are rigid compositions enriched in the HIV viral membrane...
2017: PloS One
https://www.readbyqxmd.com/read/28202027/a-novel-pfs38-protein-complex-on-the-surface-of-plasmodium-falciparum-blood-stage-merozoites
#15
Gourab Paul, Arunaditya Deshmukh, Inderjeet Kaur, Sumit Rathore, Surbhi Dabral, Ashutosh Panda, Susheel Kumar Singh, Asif Mohmmed, Michael Theisen, Pawan Malhotra
BACKGROUND: The Plasmodium genome encodes for a number of 6-Cys proteins that contain a module of six cysteine residues forming three intramolecular disulphide bonds. These proteins have been well characterized at transmission as well as hepatic stages of the parasite life cycle. In the present study, a large complex of 6-Cys proteins: Pfs41, Pfs38 and Pfs12 and three other merozoite surface proteins: Glutamate-rich protein (GLURP), SERA5 and MSP-1 were identified on the Plasmodium falciparum merozoite surface...
February 16, 2017: Malaria Journal
https://www.readbyqxmd.com/read/28199952/biopolymer-gold-nanoparticles-composite-plasmonic-thermal-history-indicator-to-monitor-quality-and-safety-of-perishable-bioproducts
#16
Yi-Cheng Wang, Lin Lu, Sundaram Gunasekaran
Quality and safety of perishable products such as foods, pharmaceutics, and biologicals is a constant concern. We have developed a plasmonic thermal history indicator (THI) taking advantage of the localized surface plasmon resonance of gold nanoparticles (AuNPs) synthesized in situ in alginate, a natural polysaccharide. The color of the THIs becomes more intense with increased storage temperature and/or duration, with the color changing from grey to red with time of exposure at high temperature (40°C). The results suggest that decreasing viscosity with increasing number of AuNPs being synthesized in the system, along with aggregation of newly synthesized AuNPs onto larger ones and their settling are potentially responsible for the distinct color change observed...
January 26, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28199758/mechanical-trap-surface-enhanced-raman-spectroscopy-for-three-dimensional-surface-molecular-imaging-of-single-live-cells
#17
Qianru Jin, Ming Li, Beril Polat, Santosh K Paidi, Aimee Dai, Amy Zhang, Jayson V Pagaduan, Ishan Barman, David H Gracias
Reported is a new shell-based spectroscopic platform, named mechanical trap surface-enhanced Raman spectroscopy (MTSERS), for simultaneous capture, profiling, and 3D microscopic mapping of the intrinsic molecular signatures on the membrane of single live cells. By leveraging the functionalization of the inner surfaces of the MTs with plasmonic gold nanostars, and conformal contact of the cell membrane, MTSERS permits excellent signal enhancement, reliably detects molecular signatures, and allows non-perturbative, multiplex 3D surface imaging of analytes, such as lipids and proteins on the surface of single cells...
February 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28199410/ultrasensitive-detection-of-hiv-1-p24-antigen-by-a-hybrid-nanomechanical-optoplasmonic-platform-with-potential-for-detecting-hiv-1-at-first-week-after-infection
#18
Priscila M Kosaka, Valerio Pini, Montserrat Calleja, Javier Tamayo
Early detection of HIV infection is the best way to prevent spread of the disease and to improve the efficiency of the antiretroviral therapy. Nucleic acid amplification tests (NAAT) have become the gold-standard for detecting low-concentrations of the virus in blood. However, these methods are technically demanding and cost-prohibitive in developing countries. Immunoassays are more affordable and can be more easily adapted for point-of-care diagnosis. However, the sensitivity so far of these methods has been too low...
2017: PloS One
https://www.readbyqxmd.com/read/28199387/dermatan-sulfate-is-a-player-in-the-transglutaminase-2-interaction-network
#19
Grzegorz Wisowski, Ewa M Koźma, Tomasz Bielecki, Adam Pudełko, Krystyna Olczyk
Transglutaminase 2 (TG2) is a multifunctional protein that is primarily engaged in cell adhesion/signaling or shows Ca2+-dependent transglutaminase activity in the extracellular space of tissues. This latter action leads to the cross-linking of the extracellular matrix (ECM) proteins. The enhanced extracellular expression of TG2 is associated with processes such as wound healing, fibrosis or vascular remodeling that are also characterized by a high deposition of dermatan sulfate (DS) proteoglycans in the ECM...
2017: PloS One
https://www.readbyqxmd.com/read/28199108/application-of-off-rate-screening-in-the-identification-of-novel-pan-isoform-inhibitors-of-pyruvate-dehydrogenase-kinase
#20
Paul A Brough, Lisa Baker, Simon Bedford, Kirsten Brown, Seema Chavda, Victoria Chell, Jalanie D'Alessandro, Nicholas G M Davies, Ben Davis, Loic Le Strat, Alba T Macias, Daniel Maddox, Patrick C Mahon, Andrew J Massey, Natalia Matassova, Sean McKenna, Jonathan D Moore, James B Murray, Christopher J Northfield, Charles Parry, Rachel Parsons, Stephen D Roughley, Terry Shaw, Heather Simmonite, Stephen Stokes, Allan Surgenor, Emma Stefaniak, Alan Robertson, Yikang Wang, Paul Webb, Neil Whitehead, Mike Wood
Libraries of nonpurified resorcinol amide derivatives were screened by surface plasmon resonance (SPR) to determine the binding dissociation constant (off-rate, kd) for compounds binding to the pyruvate dehydrogenase kinase (PDHK) enzyme. Parallel off-rate measurements against HSP90 and application of structure-based drug design enabled rapid hit to lead progression in a program to identify pan-isoform ATP-competitive inhibitors of PDHK. Lead optimization identified selective sub-100-nM inhibitors of the enzyme which significantly reduced phosphorylation of the E1α subunit in the PC3 cancer cell line in vitro...
February 15, 2017: Journal of Medicinal Chemistry
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