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Verena Wulf, Fabian Knoch, Thomas Speck, Carsten Sönnichsen
Plasmonic gold nanoparticles are normally used as sensor to detect analytes permanently bound to their surface. If the interaction between the analyte and the nanosensor surface is negligible, it only diffuses through the sensor's sensing volume, causing a small temporal shift of the plasmon resonance position. By using a very sensitive and fast detection scheme, we are able to detect these small fluctuations in the plasmon resonance. With the help of a theoretical model consistent with our detection geometry, we determine the analyte's diffusion coefficient...
December 1, 2016: Journal of Physical Chemistry Letters
Javeria Zahra, Shahid Iqbal, Kiran Zahra, Zulha Javed, Muhammad Aslam Shad, Atif Akbar, Muhammad Naeem Ashiq, Furhan Iqbal
Zinc oxide nanoparticles (ZnO NPs) have diverse utility these days ranging from being part of nanosensors to be ingredient of cosmetics. Present study was designed to report the effect of variable doses of ZnO NPs on selected aspects of male albino mice behavior. Nano particles were synthesized by sol-gel auto-combustion method (Data not shown here). 10 week old male albino mice were divided into four experimental groups; group A, B and C were orally supplemented with 50 (low dose), 300 (medium dose) and 600 mg/ml solvent/kg body weight (high dose) of ZnO NPs for 4 days...
December 8, 2016: Neurochemical Research
Katelyn M Spillane, Pavel Tolar
Antibody production and affinity maturation are driven by B cell extraction and internalization of antigen from immune synapses. However, the extraction mechanism remains poorly understood. Here we develop DNA-based nanosensors to interrogate two previously proposed mechanisms, enzymatic liberation and mechanical force. Using antigens presented by either artificial substrates or live cells, we show that B cells primarily use force-dependent extraction and resort to enzymatic liberation only if mechanical forces fail to retrieve antigen...
December 6, 2016: Journal of Cell Biology
Hairulazwan Hashim, Hisataka Maruyama, Taisuke Masuda, Fumihito Arai
Manipulation and injection of single nanosensors with high cell viability is an emerging field in cell analysis. We propose a new method using fluorescence nanosensors with a glass nanoprobe and optical control of the zeta potential. The nanosensor is fabricated by encapsulating a fluorescence polystyrene nanobead into a lipid layer with 1,3,3-trimethylindolino-6'-nitrobenzopyrylospiran (SP), which is a photochromic material. The nanobead contains iron oxide nanoparticles and a temperature-sensitive fluorescent dye, Rhodamine B...
December 1, 2016: Sensors
Alberto Bonanno, Alessandro Sanginario, Simone L Marasso, Beatrice Miccoli, Katarzyna Bejtka, Simone Benetto, Danilo Demarchi
This paper presents a customizable sensing system based on functionalized nanowires (NWs) assembled onto complementary metal oxide semiconductor (CMOS) technology. The Micro-for-Nano (M4N) chip integrates on top of the electronics an array of aluminum microelectrodes covered with gold by means of a customized electroless plating process. The NW assembly process is driven by an array of on-chip dielectrophoresis (DEP) generators, enabling a custom layout of different nanosensors on the same microelectrode array...
November 30, 2016: Sensors
F J Rawson, M T Cole, J M Hicks, J W Aylott, W I Milne, C M Collins, S K Jackson, N J Silman, P M Mendes
With the rapidly increasing demands for ultrasensitive biodetection, the design and applications of new nano-scale materials for development of sensors based on optical and electrochemical transducers have attracted substantial interest. In particular, given the comparable sizes of nanomaterials and biomolecules, there exist plenty of opportunities to develop functional nanoprobes with biomolecules for highly sensitive and selective biosensing, shedding new light on cellular behaviour. Towards this aim, herein we interface cells with patterned nano-arrays of carbon nanofibers forming a nanosensor-cell construct...
December 1, 2016: Scientific Reports
Pai Peng, Lili Shi, Huihui Wang, Tao Li
We present a conceptually new reversible nanosensor regulated by a DNA nanoswitch. This system is not only responsive to external stimuli (e.g. ATP) but also can be reversibly switched between 'OFF' and 'ON' states via toehold mediated strand displacement reactions. It functions like a molecular net woven by DNA to capture or release the target molecules. As a proof-of-principle experiment, ATP is here chosen as the model to demonstrate our new strategy, which holds great promise for applications such as switchable DNA nanomachines and nanocarriers for drug delivery...
November 29, 2016: Nucleic Acids Research
Zhili Jia, Hong Wei, Deng Pan, Hongxing Xu
Metallic nanowires (NWs) support multiple surface plasmon (SP) modes, which lead to extraordinary SP propagation behaviors. The leaky SP modes in metallic NWs connect the guiding and radiation of light at the nanometer scale. Understanding and controlling these modes are of vital importance for various nanophotonic applications. Here, we investigate the radiation from two polarization-controlled SP modes on supported silver NWs by using leakage radiation imaging and Fourier imaging techniques. The radiation directions from these modes can be clearly resolved from the Fourier images...
November 29, 2016: Nanoscale
Parikshit Moitra, Deepa Bhagat, Rudra Pratap, Santanu Bhattacharya
Plant pests exert serious effects on food production due to which the global crop yields are reduced by ~20-40 percent per year. Hence to meet the world's food needs, loses of food due to crop pests must be reduced. Herein the silicon dioxide based MEMS devices are covalently functionalized for robust and efficient optical sensing of the female sex pheromones of the pests like Helicoverpa armigera for the first time in literature. The functionalized devices are also capable of selectively measuring the concentration of this pheromone at femtogram level which is much below the concentration of pheromone at the time of pest infestation in an agricultural field...
November 28, 2016: Scientific Reports
Qijie Liang, Qian Zhang, Xiaoqin Yan, Xinqin Liao, Linhong Han, Fang Yi, Mingyuan Ma, Yue Zhang
A recyclable and green triboelectronic nanogenerator (TENG) is developed based on triboelectrification and designed cascade reactions. Once triggered by water, the TENG can fully dissolve and degrade into environmentally benign end products. With features of rapid dissolution, reproductivity, and green electronic, the TENG has potential of serving as clearable energy harvester and nanosensor for health monitoring and motion sensing.
November 25, 2016: Advanced Materials
Yanyan Hou, Satoshi Arai, Yoshiaki Takei, Atsushi Murata, Shinji Takeoka, Madoka Suzuki
Ca(2+) distribution is spatially and temporally non-uniform inside cells due to cellular compartmentalization. However, Ca(2+) sensing with small organic dyes, such as fura-2 and fluo-4, has been practically applied at a single cell level where the averaged signal from freely diffusing dye molecules is acquired. In this study, we aimed to target azide-functionalized fura-2 (N3-fura-2) to a specific site of subcellular compartments to realize focal Ca(2+) sensing. Using scAVD (single-chain avidin)-biotin interaction and a copper-free click reaction system, we linked N3-fura-2 to specifically-targeted scAVD protein fused with a red fluorescent protein mCherry, so that Ca(2+) sensors conjugated with four N3-fura-2 dyes with dibenzocyclooctyne (DBCO)-PEG4-biotin as a linker were generated at subcellular compartments in living cells...
2016: Science and Technology of Advanced Materials
Li Min Tay, Christian Wiraja, David Yeo, Yingnan Wu, Zheng Yang, Yon Jin Chuah, Eng Hin Lee, Yuejun Kang, Chenjie Xu
Chondrogenic differentiation of human mesenchymal stem cells (MSCs) in 3D hydrogel holds promise as a method for repairing injured articular cartilage. Given MSC plasticity (its potential to mature into alternative lineages), non-destructive monitoring is critical for the optimization of chondrogenic differentiation conditions and the evaluation of the final product. However, conventional validation/assessment of the differentiation process (i.e. quantitative reverse transcription polymerase chain (qRT-PCR) and histology) are end-point assays requiring disruption of the sample...
November 21, 2016: Tissue Engineering. Part C, Methods
Hui-Hui Zeng, Li Zhang, Lian-Qing Rong, Ru-Ping Liang, Jian-Ding Qiu
A bimetal lanthanide coordination polymer nanoparticle (ATP-Ce/Tb-Tris CPNs) with good biocompatibility was synthesized in Tris-HCl buffer using adenosine triphosphate (ATP) molecules as the bridge ligands. The large absorption cross section and suitable emission energy of Ce(3+) matching to the adsorption energy of Tb(3+)((4)fn) results in the efficient energy transfer from Ce(3+) to Tb(3+), thus the synthesized ATP-Ce/Tb-Tris CPNs exhibit the characteristic green emission of Tb(3+). Such energy transfer from metal to metal in fluorescent lanthanide coordination polymer nanoparticles (Ln-CPNs) has been demonstrated...
November 13, 2016: Biosensors & Bioelectronics
Kenry, Alisha Geldert, Zhuangchai Lai, Ying Huang, Peng Yu, Chaoliang Tan, Zheng Liu, Hua Zhang, Chwee Teck Lim
The novel application of two-dimensional (2D) single-layer ternary chalcogenide nanosheets as "capture-release" fluorescence-based biomolecular nanosensors is demonstrated. Fluorescently labeled biomolecular probe is first captured by the ultrathin Ta2 NiS5 nanosheets and then released upon adding analyte containing a target biomolecule due to the higher probe-target affinity. Here, the authors use a nucleic acid probe for the model target biomolecule Plasmodium lactate dehydrogenase, which is an important malarial biomarker...
November 18, 2016: Small
Jiayin Fu, Christian Wiraja, Ruiqi Chong, Chenjie Xu, Dong-An Wang
: Embryonic stem cells (ESCs)-derived embryoid body (EB) is a powerful model for the study of early embryonic development and the discovery of therapeutics for tissue regeneration. This article reports a smart nanosensor platform for labeling and tracking the survival and distribution of ESCs during the EB development in a real-time and non-invasive way. Compared with the cell tracker (i.e. DiO) and the green fluorescent protein (GFP), nanosensors provide the homogenous and highly-efficient ESC labeling...
November 11, 2016: Acta Biomaterialia
Rui Yuan, Xiaolin Yu, Yuhong Zhang, Lulu Xu, Wei Cheng, Zhiguang Tu, Shijia Ding
Herein, a simple and novel fluorescence biosensing strategy has been developed for ultrasensitive determination of microRNA (miRNA) by combining target-triggered DNA nanoassembly on quantum dots (QDs) with DNAzyme-modulated double quenching of QDs. In presence of miRNA target, the target triggered catalytic hairpin assembly (CHA) amplification and powered highly efficient DNA nanoassembly on the surface of QDs, leading to exhibition of numerous G-quadruplexes close to the QDs. The G-quadruplex folded properly and bound hemin to form a stable G-quadruplex/hemin complex...
November 5, 2016: Biosensors & Bioelectronics
Wei Xiao, Meng Xiao, Qiangqiang Fu, Shiting Yu, Haicong Shen, Hongfen Bian, Yong Tang
The detection of environmental mercury (Hg) contamination requires complex and expensive instruments and professional technicians. We present a simple, sensitive, and portable Hg(2+) detection system based on a smartphone and colorimetric aptamer nanosensor. A smartphone equipped with a light meter app was used to detect, record, and process signals from a smartphone-based microwell reader (MR S-phone), which is composed of a simple light source and a miniaturized assay platform. The colorimetric readout of the aptamer nanosensor is based on a specific interaction between the selected aptamer and Hg(2+), which leads to a color change in the reaction solution due to an aggregation of gold nanoparticles (AuNPs)...
November 8, 2016: Sensors
Mina Mehrzad-Samarin, Farnoush Faridbod, Amin Shiralizadeh Dezfuli, Mohammad Reza Ganjali
A novel optical nanosensor for detection of Metronidazole in biological samples was reported. Graphene quantum dots embedded silica molecular imprinted polymer (GQDs-embedded SMIP) was synthesized and used as a selective fluorescent probe for Metronidazole detection. The new synthesized GQDs-embedded SMIP showed strong fluorescent emission at 450nm excited at 365nm which quenched in presence of Metronidazole as a template molecule.. The quenching was proportional to the concentration of Metronidazole in a linear range of at least 0...
October 20, 2016: Biosensors & Bioelectronics
Anand M Shrivastav, Sruthi P Usha, Banshi D Gupta
An erythromycin (ERY) detection method is proposed using the fiber optic core decorated with the coatings of silver and an over layer of ERY imprinted nanoparticles. Synthesis of ERY imprinted nanoparticles is carried out using miniemulsion method. The operating range of the sensor is observed to be from 1.62×10(-3) to 100µM while the sensor possesses the linear response for ERY concentration range from 0.1 to 5µM. The sensing method shows a maximum sensitivity of 205nm/µM near ERY concentration of 0.01µM...
October 19, 2016: Biosensors & Bioelectronics
Jing Qian, Mengjuan Hua, Chengquan Wang, Kan Wang, Qian Liu, Nan Hao, Kun Wang
New strategies for onsite determination of trace 2,4,6-trinitrotoluene (TNT) explosives have become a research hotspot for homeland security needs against terrorism and environmental concerns. Herein, we designed a ratiometric fluorescence nanohybrid comprising 3-mercaptopropionic acid-capped green-emitting CdTe quantum dots (gQDs) encapsulated into SiO2 sphere and l-cysteine (Lcys)-capped red-emitting CdTe QDs (rQDs) conjugated onto SiO2 surface. The surface Lcys can be used as not only the stabilizer of the rQDs but also the primary amine provider which can react with TNT to form Meisenheimer complexes...
November 23, 2016: Analytica Chimica Acta
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