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https://www.readbyqxmd.com/read/28422382/quantum-dots-based-fluorescence-resonance-energy-transfer-biosensor-for-monitoring-cell-apoptosis
#1
Chunchuan Gu
The development of advanced methods for accurately monitoring cell apoptosis has extensive significance in the diagnostic and pharmaceutical fields. In this study, we developed a rapid, sensitive and selective approach for the detection of cell apoptosis by combining the site-specific recognition and cleavage of the DEVD-peptide with quantum dots (QDs)-based fluorescence resonance energy transfer (FRET). Firstly, biotin-peptide was conjugated on the surface of AuNPs to form AuNPs-pep through the formation of an Au-S bond...
April 19, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
https://www.readbyqxmd.com/read/28420199/detecting-single-nucleotides-by-tunneling-current-measurements-at-sub-mhz-temporal-resolution
#2
Takanori Morikawa, Kazumichi Yokota, Sachie Tanimoto, Makusu Tsutsui, Masateru Taniguchi
Label-free detection of single-nucleotides was performed by fast tunneling current measurements in a polar solvent at 1 MHz sampling rate using SiO₂-protected Au nanoprobes. Short current spikes were observed, suggestive of trapping/detrapping of individual nucleotides between the nanoelectrodes. The fall and rise features of the electrical signatures indicated signal retardation by capacitance effects with a time constant of about 10 microseconds. The high temporal resolution revealed current fluctuations, reflecting the molecular conformation degrees of freedom in the electrode gap...
April 18, 2017: Sensors
https://www.readbyqxmd.com/read/28414975/fullerene-doped-polyaniline-as-new-redox-nanoprobe-and-catalyst-in-electrochemical-aptasensor-for-ultrasensitive-detection-of-mycobacterium-tuberculosis-mpt64-antigen-in-human-serum
#3
Lijuan Bai, Yuhan Chen, Yan Bai, Yongjie Chen, Jing Zhou, Ailong Huang
Tuberculosis caused by Mycobacterium tuberculosis (MTB) is still a major threat to global public health. However, the existing methods for MTB detection are usually complicated and time consuming with unsatisfactory sensitivity and specificity. In this work, a relatively simple and ultrasensitive electrochemical aptasensor based on novel signal generation and amplification was constructed for the determination of MTB antigen MPT64. The coil-like fullerene (C60)-doped polyaniline (C60-PAn) nanohybrids with large surface area, abundant active groups and excellent electric performance were synthesized and used both as new redox nanoprobe and catalyst for the generation and amplification of electrochemical signal for the first time...
April 12, 2017: Biomaterials
https://www.readbyqxmd.com/read/28414417/graphene-nanoprobes-for-real-time-monitoring-of-isothermal-nucleic-acid-amplification
#4
Fan Li, Xiaoguo Liu, Bin Zhao, Juan Yan, Qian Li, Ali Aldalbahi, Jiye Shi, Shiping Song, Chunhai Fan, Lihua Wang
Isothermal amplification is an efficient way to amplify DNA with high accuracy, however, the real-time monitoring for quantification analysis mostly relied on expensive and precisely designed probes. In the present study, Graphene oxide (GO)-based nano probe was used to real-time monitor the isothermal amplification process. The interaction between GO and different DNA structures was systematically investigated, including single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), DNA 3-helix, and long rolling circle amplification (RCA) and hybridization chain reaction (HCR) products, which existed in one-, two- and three-dimensional structures...
April 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28412660/gold-nanoparticle-based-low-limit-of-detection-love-wave-biosensor-for-carcinoembryonic-antigens
#5
Shuangming Li, Ying Wan, Yan Su, Chunhai Fan, Venkat R Bhethanabotla
In this work, a Love wave biosensing platform is described for detecting cancer-related biomarker carcinoembryonic antigen (CEA). An ST 90°-X quartz Love wave device with a layer of SiO2 waveguide was combined with gold nanoparticles (Au NPs) to amplify the mass loading effect of the acoustic wave sensor to achieve a limit of detection of 37pg/mL. The strategy involves modifying the Au NPs with anti-CEA antibody conjugates to form nanoprobes in a sandwich immunoassay. The unamplified detection limit of the Love wave biosensor is 9...
April 12, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28411797/a-label-free-fluorescence-turn-on-assay-for-glutathione-detection-by-using-mno2-nanosheets-assisted-aggregation-induced-emission-silica-nanospheres
#6
Xiaobin Zhang, Rongmei Kong, Qingqing Tan, Fei Qu, Fengli Qu
Glutathione (GSH) serves several vital biological functions and its abnormal levels are associated with many diseases. Simple and sensitive methods capable of detecting GSH are desired for better understanding the mechanism of diseases. In this work, a label-free MnO2 nanosheets assisted aggregation-induced emission (AIE)-silica nanospheres (SiO2 NPs) nanoprobe for fluorescent "turn-on" detection of GSH with high sensitivity was reported for the first time. The anionic tetraphenylethylene derivative 3 (TPE3) was synthesized and employed as the AIE-active probe, which can be aggregated on the uncoated amino-functionalized SiO2 NPs to form AIE-SiO2 NPs and emitted strong fluorescence...
July 1, 2017: Talanta
https://www.readbyqxmd.com/read/28411533/label-free-upconversion-nanoparticles-based-fluorescent-probes-for-sequential-sensing-of-cu-2-pyrophosphate-and-alkaline-phosphatase-activity
#7
Fangfang Wang, Cuiling Zhang, Qin Xue, Huaping Li, Yuezhong Xian
An efficient near-infrared fluorescence probe has been developed for the sequential detection of Cu(2+), pyrophosphate (P2O7(4-), PPi), and alkaline phosphatase (ALP), which is based on the "off-on-off" fluorescence switch of branched polyethyleneimine (PEI)-capped NaGdF4:Yb/Tm upconversion nanoparticles (UCNPs). The fluorescence is quenched via energy transfer from UCNPs to Cu(2+) for the coordination of PEI with Cu(2+). The strong affinity between Cu(2+) and PPi leads to the formation of Cu(2+)-PPi complex and results in the detachment of Cu(2+) from the surface of UCNPs, thus the fluorescence is triggered on...
April 12, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28411532/one-pot-loading-high-content-thionine-on-polydopamine-functionalized-mesoporous-silica-nanosphere-for-ultrasensitive-electrochemical-immunoassay
#8
Guosong Lai, Min Zheng, Wenjie Hu, Aimin Yu
A thionine (TH)-doped mesoporous silica nanosphere (MSN)/polydopamine (PDA) nanocomposite was synthesized for developing a new signal transduction strategy of electrochemical immunoassay. This nanocomposite was synthesized through one-pot loading of TH and in situ formation of PDA-coating on MSN. After antibody labeling, the obtained nanoprobe was used for the signal tracing of sandwich immunoassay at a magnetic bead-assay platform. Based on the specific capture of the MSN-TH/PDA nanoprobes through sandwich immunoreaction to form a magnetic immunocomplex and the following treatment of the immunocomplex with a NaOH solution, the PDA film coated on MSN was destroyed to release TH tags from the nanoprobe...
April 11, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28411450/activatable-near-infrared-dye-conjugated-hyaluronic-acid-based-nanoparticles-as-a-targeted-theranostic-agent-for-enhanced-fluorescence-ct-photoacoustic-imaging-guided-photothermal-therapy
#9
Xiaolong Liang, Lei Fang, Xiaoda Li, Xu Zhang, Fan Wang
Targeted theranostic nano-system integrating functions of both diagnosis and therapy shows great potential for improving diagnosis and therapeutic efficacy. Herein, multifunctional nanoparticle based on activatable hyaluronic acid (HA) conjugating two near-infrared (NIR) dyes of Cy5.5 and IR825 was successfully designed and fabricated, and simultaneously used as a carrier for encapsulating perfluorooctylbromide (PFOB). In this system, PFOB showed good capability to absorb the X-rays, Cy5.5 on the outer surface acted as a fluorescent dye activatable by hyaluronidases (Hyals) in the tumor, and IR825 in the core as a photothermal agent...
April 8, 2017: Biomaterials
https://www.readbyqxmd.com/read/28402594/tumor-microenvironment-triggered-aggregation-of-antiphagocytosis-99m-tc-labeled-fe3-o4-nanoprobes-for-enhanced-tumor-imaging-in-vivo
#10
Zhenyu Gao, Yi Hou, Jianfeng Zeng, Lei Chen, Chunyan Liu, Wensheng Yang, Mingyuan Gao
A tumor microenvironment responsive nanoprobe is developed for enhanced tumor imaging through in situ crosslinking of the Fe3 O4 nanoparticles modified with a responsive peptide sequence in which a tumor-specific Arg-Gly-Asp peptide for tumor targeting and a self-peptide as a "mark of self" are linked through a disulfide bond. Positioning the self-peptide at the outmost layer is aimed at delaying the clearance of the nanoparticles from the bloodstream. After the self-peptide is cleaved by glutathione within tumor microenvironment, the exposed thiol groups react with the remaining maleimide moieties from adjacent particles to crosslink the particles in situ...
April 12, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28401227/in-situ-mrna-isolation-from-a-microfluidic-single-cell-array-using-an-external-afm-nanoprobe
#11
Xuan Li, Yinglei Tao, Do-Hyun Lee, Hemantha K Wickramasinghe, Abraham P Lee
We present an in situ mRNA extraction platform to quantify marker-genes' expression levels of single target cells within high-density microfluidic trapping arrays. This platform enables single-cell transcriptomic analysis to reveal in-depth information of cellular mechanisms and population heterogeneity. Although microfluidic technology enables the automation of single-cell sorting, trapping and identification, most developed microfluidic devices are closed off and prevent single-cell access by external analytical equipment...
April 12, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28395778/an-on-off-on-fluorescent-nanoprobe-for-recognition-of-chromium-vi-and-ascorbic-acid-based-on-phosphorus-nitrogen-dual-doped-carbon-quantum-dot
#12
Xiaojuan Gong, Yang Liu, Zhenhua Yang, Shaomin Shuang, Zeyu Zhang, Chuan Dong
Chromium (VI) [Cr(VI)] is a harsh environmental contaminates and has been proved to be highly toxic, carcinogenic and mutagenic. Therefore, developing an inexpensive, good selective and highly sensitive nanoprobe for the detection of Cr(VI) is in urgent demand. Recently, the highly fluorescent carbon quantum dots (CQDs) have been successfully utilized as efficient fluorescent nanoprobes for the detection of ions, pH and molecular substances. In this work, an "on-off" fluorescence phosphorus/nitrogen dual-doped CQDs (PNCQDs) probe was developed for the determination of Cr(VI) based on inner filter effect (IFE)...
May 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28391081/glucose-decorated-gold-nanoclusters-a-membrane-potential-independent-fluorescence-probe-for-rapid-identification-of-cancer-cells-expressing-glut-receptors
#13
Sanjay Singh
The effective nanomedicines require nanoparticles to attach or adhere to the cell surface, which is dictated by several parameters of nanoparticles such as shape, size, charge, and composition. However, these parameters lead to the membrane potential dependent non-specific delivery of therapeutic or imaging nanosystems into cancer cells. This leads to significant complications and results into the serious impediment to effective treatment of cancer. Cancer cells are known to metabolize high amount of glucose in order to support their rapid proliferation and expansion...
April 1, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28390490/determination-of-nanomolar-levels-of-reactive-oxygen-species-in-microorganisms-and-aquatic-environments-using-a-single-nanoparticle-based-optical-sensor
#14
Yura Kim, Youngho Kim, Jinhee Choi, Taewook Kang, Inhee Choi
Reactive oxygen species (ROS) are strong oxidants, and have attracted considerable attention in both biological and environmental fields. Although various methods for ROS detection, including optical and electrochemical techniques, have been developed, they still face challenging issues in terms of poor sensitivity, reproducibility, stability, and in vivo applicability. Here, we present a sensitive and selective optical sensor for ROS detection, based on single plasmonic nanoprobes and redox-active cytochrome c (Cyt c)-mediated plasmon resonance energy transfer...
May 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28383175/color-convertible-unimolecular-micelle-based-activatable-fluorescent-probe-for-tumor-specific-detection-and-imaging-in-vitro-and-in-vivo
#15
Yu Huang, Feng Qiu, Dong Chen, Lingyue Shen, Shuting Xu, Dongbo Guo, Yue Su, Deyue Yan, Xinyuan Zhu
Recent years have witnessed significant progress in molecular probes for cancer diagnosis. However, the conventional molecular probes are designed to be "always-on" by attachment of tumor-targeting ligands, which limits their abilities to diagnose tumors universally due to the variations of targeting efficiency and complex environment in different cancers. Here, it is proposed that a color-convertible, activatable probe is responding to a universal tumor microenvironment for tumor-specific diagnosis without targeting ligands...
April 6, 2017: Small
https://www.readbyqxmd.com/read/28382162/incorporating-gold-nanoclusters-and-target-directed-liposomes-as-a-synergistic-amplified-colorimetric-sensor-for-her2-positive-breast-cancer-cell-detection
#16
Yu Tao, Mingqiang Li, Bumjun Kim, Debra T Auguste
Breast cancer is the second leading cause of cancer-related mortality in women. Successful development of sensitive nanoprobes for breast cancer cell detection is of great importance for breast cancer diagnosis and symptomatic treatment. Herein, inspired by the intrinsic peroxidase property of gold nanoclusters, high loading, and targeting ability of ErbB2/Her2 antibody functionalized liposomes, we report that gold nanoclusters-loaded, target-directed, functionalized liposomes can serve as a robust sensing platform for amplified colorimetric detection of HER2-positive breast cancer cells...
2017: Theranostics
https://www.readbyqxmd.com/read/28382156/theranostic-nucleic-acid-binding-nanoprobe-exerts-anti-inflammatory-and-cytoprotective-effects-in-ischemic-injury
#17
Howard H Chen, Hushan Yuan, Hoonsung Cho, Yan Feng, Soeun Ngoy, Anand T N Kumar, Ronglih Liao, Wei Chao, Lee Josephson, David E Sosnovik
Extracellular nucleic acids are proinflammatory molecules that have been implicated in a diverse range of diseases. We report here the development of a multivalent nucleic acid scavenging nanoprobe, where the fluorochrome thiazole orange (TO) is conjugated to a polymeric 40 kDa dextran carrier. Dextran-TO (Dex-TO) has nanomolar affinity for mammalian and bacterial nucleic acids and attenuates the production of inflammatory cytokines from activated macrophages exposed to DNA and RNA. Mice with myocardial ischemia reperfusion that were treated with Dex-TO showed a decrease in myocardial macrophage infiltration at 24 hours (p<0...
2017: Theranostics
https://www.readbyqxmd.com/read/28371584/ultrasmall-ferrite-nanoparticles-synthesized-via-dynamic-simultaneous-thermal-decomposition-for-high-performance-and-multifunctional-t1-magnetic-resonance-imaging-contrast-agent
#18
Huan Zhang, Li Li, Xiao Li Liu, Ju Jiao, Cheng-Teng Ng, Jia Bao Yi, Yan E Luo, Boon-Huat Bay, Ling Yun Zhao, Ming Li Peng, Ning Gu, Hai Ming Fan
Large-scale synthesis of monodisperse ultrasmall metal ferrite nanoparticles as well as understanding the correlations between chemical composition and MR signal enhancement is critical for developing next-generation, ultrasensitive T1 magnetic resonance imaging (MRI) nanoprobes. Herein, taking ultrasmall MnFe2O4 nanoparticles (UMFNPs) as a model system, we report a general dynamic simultaneous thermal decomposition (DSTD) strategy for controllable synthesis of monodisperse ultrasmall metal ferrite nanoparticles with sizes smaller than 4 nm...
April 6, 2017: ACS Nano
https://www.readbyqxmd.com/read/28367627/ultrahigh-sensitivity-multifunctional-nanoprobe-for-the-detection-of-hydroxyl-radical-and-evaluation-of-heavy-metal-induced-oxidative-stress-in-live-hepatocyte
#19
Quanwei Guo, Yuxin Liu, Qi Jia, Ge Zhang, Huimin Fan, Lidong Liu, Jing Zhou
Hydroxyl radical ((•)OH) is an important marker of the progress of heavy metal induced oxidative stress. However, most reported probes and detection methods cannot meet the need of monitoring the (•)OH concentration within the whole progress because of the limited linear range. Besides, a low detection limit, high sensitivity, and good selectivity were also required. In this study, an ultrahigh sensitivity multifunctional nanoprobe (ICG-modified NaLuF4:Yb,Er) was developed to evaluate heavy metal induced oxidative stress by detecting (•)OH concentration, with a colorimetric, upconversion luminescence, and photothermal stepped method...
April 11, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28363193/dual-mode-electrochemical-analysis-of-microrna-21-using-gold-nanoparticle-decorated-mos2-nanosheet
#20
Shao Su, Wenfang Cao, Wei Liu, Zaiwei Lu, Dan Zhu, Jie Chao, Lixing Weng, Lihua Wang, Chunhai Fan, Lianhui Wang
The detection of microRNA plays an important role in early cancer diagnosis. Herein, a dual-mode electronic biosensor was developed for microRNA-21 (miRNA-21) detection based on gold nanoparticle-decorated MoS2 nanosheet (AuNPs@MoS2). A classical DNA "sandwich" structure was employed to construct MoS2-based electrochemical sensor, including capture DNA, target miRNA-21 and DNA-modified nanoprobe. [Fe(CN)6](3-/4-) and [Ru(NH3)6](3+) were selected as electrochemical indicators to monitor the preparation process and evaluate the performance of MoS2-based electrochemical biosensor by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), respectively...
March 20, 2017: Biosensors & Bioelectronics
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