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https://www.readbyqxmd.com/read/28738656/an-ultrasensitive-fluorescent-nanosensor-for-trypsin-based-on-upconversion-nanoparticles
#1
Mingmin Wu, Xiaoyong Wang, Kun Wang, Zijian Guo
Trypsin and its inhibitors are relevant to many physiological processes and diseases. In this study, a nanosensor capable of detecting trypsin and its inhibitors was designed based on the fluorescence resonance energy transfer (FRET) between upconversion nanoparticle (UCNP) and gold nanoparticle (AuNP). UCNP and AuNP were linked by a trypsin-sensitive peptide DDDDARC, forming the non-fluorescent UCNP-peptide-AuNP nanosensor. In the presence of trypsin, the peptide was cleaved and the quenched fluorescence was restored; in the presence of trypsin inhibitors, the recovery of the fluorescence was decreased...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738561/silver-triangular-nanoplates-as-an-high-efficiently-fret-donor-acceptor-of-upconversion-nanoparticles-for-ultrasensitive-turn-on-off-protamine-and-trypsin-sensor
#2
Hongyu Chen, Aijin Fang, Youyu Zhang, Shouzhuo Yao
Silver triangular nanoplates (STNPs) as a high efficient fluorescence quenching reagent of upconversion nanoparticles (UCNPs) was used to constract a novel label-free fluorescence nanosensor for ultrasensitive detection of protamine and trypsin based on fluorescence resonance energy transfer (FRET) between STNPs and UCNPs. In this assay, the negatively charged STNPs can bind with positively charged UCNPs through electrostatic interaction, and then quenched the fluorescence of UCNPs. When protamine was added to the mixture of UCNPs-STNPs, the STNPs interacted with protamine and then detached from the surface of UCNPs and aggregated, which result in the recovery of the fluorescence of UCNPs...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28737377/carbon-dot-based-naphthalimide-coupled-fret-pair-for-highly-selective-ratiometric-detection-of-thioredoxin-reductase-and-cancer-screening
#3
Jagpreet Singh Sidhu, Ashutosh Singh, Neha Garg, Narinder Singh
The Fluorescence resonance energy transfer (FRET) mechanism has been established between the carbon dots (CDs) and naphthalimide to monitor the activity of thioredoxin reductase (TrxR), which is often overexpressed in many cancer cells. The naphthalimide moiety was covalently attached to the surface of CDs through a disulfide linkage. In the normal cell conditions (when devoid of high concentrations of TrxR), the CDs act as an energy donor and naphthalimide acts as an acceptor, which establishes the FRET pair as interpreted from the emission at λem =565 nm, when excited at λex =360 nm...
July 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28736785/rapid-and-ultrasensitive-detection-of-endocrine-disrupting-chemicals-using-a-nanosensor-enabled-cell-based-platform
#4
Ngoc D B Le, Xian Wang, Yingying Geng, Rui Tang, Gulen Yesilbag Tonga, Ziwen Jiang, Vincent M Rotello
Endocrine disrupting chemicals (EDCs) interact with estrogen receptors (ERs), causing a broad range of adverse health effects. Current assays for EDC activity are slow and often lack sensitivity. We report here an ultra-sensitive nanosensor that can detect estrogenic cellular changes in ER(+) MCF-7 cells rapidly (minutes) at several orders of magnitude lower than the generally used assays. Notably, the sensor responses at these ultra-low EDC levels correlated with an increased synthesis phase (S-phase) cell population of EDC-treated cells...
July 24, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28725884/an-enzyme-mediated-competitive-colorimetric-sensor-based-on-au-ag-bimetallic-nanoparticles-for-highly-sensitive-detection-of-disease-biomarkers
#5
Binfeng Yin, Wenshu Zheng, Mingling Dong, Wenbo Yu, Yiping Chen, Sang Woo Joo, Xingyu Jiang
We developed a competitive colorimetric nanosensor based on Au@Ag bimetallic nanoparticles for the detection of interleukin-6 (IL-6) in clinical samples. Antibody-conjugated magnetic nanoparticles (MNPs) and polystyrene (PS) microparticles conjugated with both catalase and a secondary antibody can form sandwich structures that enable one-step target enrichment and separation. The catalase on the surface of the PS can catalyze the hydrolysis of hydrogen peroxide (H2O2) to regulate the deposition of Ag(+) on the surface of gold nanoparticles (AuNPs), and forms different sizes and amounts of Au@Ag bimetallic nanoparticles (Au@AgNPs) which produce a distinct color signal for readout with the naked eye...
July 20, 2017: Analyst
https://www.readbyqxmd.com/read/28723214/electrokinetic-manipulation-integrated-plasmonic-photonic-hybrid-raman-nanosensors-with-dually-enhanced-sensitivity
#6
Chao Liu, Zheng Wang, Erwen Li, Zexi Liang, Swapnajit Chakravarty, Xiaochuan Xu, Alan X Wang, Ray T Chen, Donglei Fan
To detect biochemicals with ultrahigh sensitivity, efficiency, reproducibility, and specificity has been the holy grail in the development of nanosensors. In this work, we report an innovative type of photonic-plasmonic hybrid Raman nanosensor integrated with electrokinetic manipulation by rational design, which offers dual mechanisms that enhance the sensitivity for molecule detection directly in solution. For the first time, we integrate large arrays of synthesized plasmonic nanocapsules with densely surface distributed silver (Ag) nanoparticles (NPs) on lithographically patterned photonic crystal slabs via electric-field assembling...
March 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723188/salt-gradient-improving-signal-to-noise-ratio-in-solid-state-nanopore
#7
Jingjie Sha, Hongjiao Shi, Yin Zhang, Chen Chen, Lei Liu, Yunfei Chen
As the single molecule detection tool, solid-state nanopores are being applied in more and more fields, such as medicine controlled delivery, ion conductance microscopes, nanosensors, and DNA sequencing. The critical information obtained from nanopores is the signal collected, which is the ionic block current caused by the molecules passing through the pores. However, the information collected is, in part, impeded by the relatively low signal-to-noise ratio of the current solid-state nanopore measurements. Here, we report that using a salt gradient across the nanopore could improve the signal-to-noise ratio when molecules translocate through Si3N4 nanopore...
April 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723143/an-ultrasensitive-plasmonic-nanosensor-for-aldehydes
#8
Meng Li, Lei Shi, Tao Xie, Chao Jing, Guangli Xiu, Yi-Tao Long
Glucose is the most common but important aldehyde, and it is necessary to create biosensors with high sensitivity and anti-interference to detect it. Under the existence of silver ions and aldehyde compounds, single gold nanoparticles and freshly formed silver atoms could respectively act as core and shell, which finally form a core-shell structure. By observing the reaction between glucose and Tollens' reagent, metallic silver was found to be reduced on the surface of gold nanoparticles and formed Au@Ag nanoparticles that lead to a direct wavelength shift...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28718456/graphene-oxide-and-dna-aptamer-based-sub-nanomolar-potassium-detecting-optical-nanosensor
#9
Debopam Datta, Ketaki Sarkar, Souvik Mukherjee, Xenia Meshik, Michael A Stroscio, Mitra Dutta
Quantum-dot (QD) based nanosensors are frequently used by researchers to detect small molecules, ions and different biomolecules. In this article, we present a sensor complex/system comprised of deoxyribonucleic acid (DNA) aptamer, gold nanoparticle and semiconductor QD, attached to a graphene oxide (GO) flake for detection of potassium. As reported herein, it is demonstrated that QD-aptamer-quencher nanosensor functions even when tethered to GO, opening the way to future applications where sensing can be accomplished simultaneously with other previously demonstrated applications of GO such as serving as a nanocarrier for drug delivery...
August 11, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28714693/stochastic-simulation-of-dopamine-neuromodulation-for-implementation-of-fluorescent-neurochemical-probes-in-the-striatal-extracellular-space
#10
Abraham Beyene, Ian McFarlane, Rebecca Pinals, Markita P Landry
Imaging the dynamic behavior of neuromodulatory neurotransmitters in the extracelluar space arising from individual quantal releases would constitute a major advance in neurochemical imaging. Spatial and temporal resolution of these highly stochastic neuromodulatory events requires concurrent advances in the chemical development of optical nanosensors selective for neuromodulators in concert with advances in imaging methodologies to capture millisecond neurotransmitter release. Herein, we develop and implement a stochastic model to describe dopamine dynamics in the extracellular space (ECS) of the brain dorsal striatum to guide the design and implementation of fluorescent neurochemical probes that record neurotransmitter dynamics in the ECS...
July 17, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28711028/fluorescence-based-cdte-nanosensor-for-sensitive-detection-of-cytochrome-c
#11
Rehab M Amin, Souad A Elfeky, Thomas Verwanger, Barbara Krammer
Cytochrome c (Cyt c) is commonly used as intrinsic biomarker for several characteristics of the cell such as respiration, energy level and apoptosis. In the present study a simple colorimetric sensor should be developed and tested for the real-time detection of Cyt c in living cells. We synthesized cadmium telluride quantum dots (CdTe QDs) capped with thioglycolic acid (TGA) as a fluorometric Cyt c nanosensor. The synthesized TGA/CdTe QDs nanosensor was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and absorption as well as fluorescence spectrophotometry...
July 8, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28707875/nir-ratiometric-luminescence-detection-of-ph-fluctuation-in-living-cells-with-hemicyanine-derivative-assembled-upconversion-nanophosphors
#12
Haixia Li, Hao Dong, Ming-Ming Yu, Chunxia Liu, Zhan-Xian Li, Liu-He Wei, Lingdong Sun, Hongyan Zhang
It is crucial for cell physiology to keep the homeostasis of pH, and it is highly demanded yet challenging to develop luminescence resonance energy transfer (LRET) based near infrared (NIR) ratiometric luminescent sensor for the detection of pH fluctuation with NIR excitation. As promising energy donors for LRET, upconversion nanoparticles (UCNPs) have been widely used to fabricate nanosensors, but the relatively low LRET efficiency limits their application in bioassay. To improve the LRET efficiency, core/shell/shell structured β-NaGdF4@NaYF4:Yb,Tm@NaYF4 UCNPs were prepared and decorated with hemicyanine dyes as an LRET-based NIR ratiometric luminescent pH fluctuation-nanosensor for the first time...
July 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28703226/a-paper-polymer-hybrid-cd-like-microfluidic-spinchip-integrated-with-dna-functionalized-graphene-oxide-nanosensors-for-multiplex-qlamp-detection
#13
Maowei Dou, Sharma T Sanjay, Delfina C Dominguez, Sihui Zhan, XiuJun Li
A paper/poly(methyl methacrylate) (PMMA) hybrid CD-like microfluidic SpinChip integrated with DNA probe-functionalized graphene oxide (GO) nanosensors was developed for multiplex quantitative LAMP detection (mqLAMP). This approach can simply and effectively address a major challenging problem of multiplexing in current LAMP methods.
July 13, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28696331/molecular-beacon-anchored-onto-a-graphene-oxide-substrate
#14
Arash Darbandi, Debopam Datta, Krunal Patel, Gary Lin, Michael A Stroscio, Mitra Dutta
In this article, we report a graphene oxide-based nanosensor incorporating semiconductor quantum dots linked to DNA-aptamers that functions as a 'turn-off' fluorescent nanosensor for detection of low concentrations of analytes. A specific demonstration of this turn-off aptasensor is presented for the case of the detection of mercury (II) ions. In this system, ensembles of aptamer-based quantum-dot (QD) sensors are anchored on graphene oxide (GO) flakes which provide a platform for analyte detection in the vicinity of GO operating in the "turn-off" mode...
July 11, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28693314/plasmonic-vertically-coupled-complementary-antennas-for-dual-mode-infrared-molecule-sensing
#15
Xiahui Chen, Chu Wang, Yu Yao, Chao Wang
Here we report an infrared plasmonic nanosensor for label-free, sensitive, specific, and quantitative identification of nanometer-sized molecules. The device design is based on vertically coupled complementary antennas with densely patterned hot-spots. The elevated metallic nanobars and complimentary nanoslits in the substrate strongly couple at vertical nano-gaps between them, resulting in dual-mode sensing dependent on the light polarization parallel or perpendicular to the nanobars. We demonstrate experimentally that a monolayer of octadecanethiol (ODT) molecules (thickness 2...
July 10, 2017: ACS Nano
https://www.readbyqxmd.com/read/28691484/nitric-oxide-nanosensors-for-predicting-the-development-of-osteoarthritis-in-rat-model
#16
Pan Jin, Christian Wiraja, Jinmin Zhao, Jinlu Zhang, Li Zheng, Chenjie Xu
Osteoarthritis (OA) is a chronic arthritic disease with the overproduction of inflammatory factors such as nitric oxide (NO). This study develops a NO nanosensor to predict the OA development. The nanosensor is synthesized by encapsulating NO sensing molecules (i.e. 4-amino-5-methylamino-2',7'-difluorofluorescein Diaminofluorescein-FM, DAF-FM) within biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles. In vitro, the nanosensor allows the monitoring of NO release in IL-1β-stimulated chondrocytes and the alleviative effect of NG-Monomethyl-L-arginine (L-NMMA, a NO inhibitor) and Andrographolide (an anti-inflammatory agent)...
July 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28687039/carbon-nanodots-as-dual-mode-nanosensors-for-selective-detection-of-hydrogen-peroxide
#17
Cheng-Long Shen, Li-Xia Su, Jin-Hao Zang, Xin-Jian Li, Qing Lou, Chong-Xin Shan
Hydrogen peroxide (H2O2) is an important product of oxidase-based enzymatic reactions, such as glucose/glucose oxidase (GOD) reaction. Therefore, the probing of generated H2O2 for achieving the detection of various carbohydrates and their oxidases is very significative. Herein, we report one kind of dual-emission carbon nanodots (CDs) that can serve as novel dual-mode nanosensors with both fluorometric and colorimetric output for the selective detection of H2O2. The dual-model nanosensors are established only by the undecorated dual-emission CDs, where significant fluorometric and colorimetric changes are observed with the addition of different concentrations of H2O2 in the CD solution, which benefit to the achievement of the naked-eye detection for H2O2...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28672193/quantitative-differentiation-of-multiple-virus-in-blood-using-nanoporous-silicon-oxide-immunosensor-and-artificial-neural-network
#18
W Chakraborty, R Ray, N Samanta, C RoyChaudhuri
In spite of the rapid developments in various nanosensor technologies, it still remains challenging to realize a reliable ultrasensitive electrical biosensing platform which will be able to detect multiple viruses in blood simultaneously with a fairly high reproducibility without using secondary labels. In this paper, we have reported quantitative differentiation of Hep-B and Hep-C viruses in blood using nanoporous silicon oxide immunosensor array and artificial neural network (ANN). The peak frequency output (fp) from the steady state sensitivity characteristics and the first cut off frequency (fc) from the transient characteristics have been considered as inputs to the multilayer ANN...
June 24, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28665432/a-cracking-assisted-micro-nanofluidic-fabrication-platform-for-silver-nanobelt-arrays-and-nanosensors
#19
Dong-Joo Kim, Dogyeong Ha, Qitao Zhou, Ashish Kumar Thokchom, Ji Won Lim, Jongwan Lee, Jun Gyu Park, Taesung Kim
Nanowires (NWs) with a high surface-to-volume ratio are advantageous for bio- or chemical sensor applications with high sensitivity, high selectivity, rapid response, and low power consumption. However, NWs are typically fabricated by combining several nanofabrication and even microfabrication processes, resulting in drawbacks such as high fabrication cost, extensive labor, and long processing time. Here, we show a novel NW fabrication platform based on "crack-photolithography" to produce a micro-/nanofluidic channel network...
July 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/28650820/terahertz-channel-model-and-link-budget-analysis-for-intrabody-nanoscale-communication
#20
Hadeel Elayan, Raed M Shubair, Josep M Jornet, Pedram Johari
Nanosized devices operating inside the human body open up new prospects in the healthcare domain. In vivo wireless nanosensor networks (iWNSNs) will result in a plethora of applications ranging from intrabody health-monitoring to drug- delivery systems. With the development of miniature plasmonic signal sources, antennas and detectors, wireless communications among intrabody nanodevices will expectedly be enabled at both the Terahertz Band (0.1-10 THz) as well as optical frequencies (400-750 THz). This result motivates the analysis of the phenomena affecting the propagation of electromagnetic signals inside the human body...
June 22, 2017: IEEE Transactions on Nanobioscience
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