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Jiaohan Guo, Kevin Black, Jiawen Hu, Mahi R Singh
We developed a theory for the fluorescence (FL) for quantum emitter and double metallic nanoshell dimer hybrids using the density matrix method. The dimer is made from two identical double metallic nanoshells, which are made of a dielectric core, a gold metallic shell and a dielectric spacer layer. The quantum emitters are deposited on the surface of the spacer layers of the dimers due to the electrostatic absorptions. We consider that dimer hybrids are surrounded by biological cells. This can be achieved by injecting them in human or animal cells...
March 16, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Yan-Mei Lei, Bai-Qi Xiao, Wen-Bin Liang, Ya-Qin Chai, Ruo Yuan, Ying Zhuo
It is well known that the conventional electrochemiluminescence (ECL) biosensor rely on the heterogeneous assay formats that involves the immobilization of biorecognition probe on the electrode surface before signal collection, which inevitably cause the efficiency of bio-recognition reactions to be limited owing to the existence of local steric hindrance. Herein, a robust, magnetic, and self-accelerated ECL nanosensor based on the multifunctionalized cobalt ferrite magnetite nanoparticles (CoFe2 O4 MNPs) was firstly designed for copper ion (Cu2+ ) detection in quasi-homogeneous system...
March 7, 2018: Biosensors & Bioelectronics
Xiaonan Gao, Lulu Jiang, Bo Hu, Fanpeng Kong, Xiaojun Liu, Kehua Xu, Bo Tang
The gold nanosensors based on Au-S bond have been widely applied to biochemical detections. However, the signal distortion caused by biothiols has been seldom mentioned and urgently needed to be solved. Herein, we designed a novel but easily assembled gold nanoprobe by coupling selenol-modified peptide with FITC onto the gold nanoparti-cle's surface via Au-Se bond for florescence imaging of a tumor marker matrix metalloproteinases 2 (MMP-2). The Au-Se probes display a higher signal-noise ratio (SNR, 10.1) and a lower detection limit (LOD, 1...
March 9, 2018: Analytical Chemistry
Haijuan Zhang, Baoxin Zhang, Cuixia Di, Mohammad Chand Ali, Jia Chen, Zhan Li, Jing Si, Hong Zhang, Hongdeng Qiu
As an important biomarker for the early stage of apoptosis, cytochrome c (Cyt c) has been recognized as a key component of the intrinsic apoptotic pathway. Fluorescence imaging tools enabling detection of Cyt c in apoptotic signaling have been rarely explored, though they are critical for cell biology and clinical theranostics. Here, we designed a novel label-free N-doped carbon dot (N-doped CD)-based nanosensor that enables fluorescence activation imaging of Cyt c release in cell apoptosis. The inner filter effect of Cyt c towards N-doped CDs enabled quantitative Cyt c measurement...
March 6, 2018: Nanoscale
Jung-Rok Lee, Iris Appelmann, Cornelius Miething, Tyler O Shultz, Daniel Ruderman, Dokyoon Kim, Parag Mallick, Scott W Lowe, Shan X Wang
Cancer proteomics is the manifestation of relevant biological processes in cancer development. Thus, it reflects the activities of tumor cells, host-tumor interactions, and systemic responses to cancer therapy. To understand the causal effects of tumorigenesis or therapeutic intervention, longitudinal studies are greatly needed. However, most of the conventional mouse experiments are unlikely to accommodate frequent collection of serum samples with a large enough volume for multiple protein assays towards single-object analysis...
2018: Theranostics
Yanmei Si, Yaocai Bai, Xiaojie Qin, Jun Li, Wenwan Zhong, Zhijun Xiao, Jishan Li, Yadong Yin
A novel ratiometric surface-enhanced Raman scattering (SERS) nanosensor has been developed to probe the activity of endonuclease under in vitro and in living cells conditions. The optimized alloyed Au/Ag nanoparticles (Au/AgNPs) were synthesized as the SERS substrate, which combined the superior properties of both the pure Au and Ag nanoparticles: they exhibit excellent plasmonic property with high chemical stability and low cytotoxicity. They were then employed for quantitative detection of endonuclease through functionalization with single-stranded DNA (ssDNA) carrying 3-(4-(phenylethynyl)benzylthio) propanoic acid (PEB) as endonuclease-responsive SERS signaling molecule, and 4-thiol phenylacetylene (TPA) as the internal standard SERS signaling molecule...
March 5, 2018: Analytical Chemistry
Jie Tan, Xiaoming Zhang, Wenguan Liu, Xiujie He, Mingwen Zhao
Using non-equilibrium Green's function formalism combined with density functional theory (DFT) calculations, we investigate the significant changes in electronic and transport properties of triangle graphene spirals (TGSs) in response to external strain. Tunable negative differential resistance (NDR) behavior is predicted. The NDR bias region, NDR width, and peak-to-valley ratio can be well tuned by external strain. Further analysis shows that these peculiar properties can be attributed to the dispersion widths of the pz orbitals...
February 23, 2018: Nanotechnology
Fei Han, S R C Vivekchand, Alexander H Soeriyadi, Yuanhui Zheng, J Justin Gooding
Herein is described a facile method for the assembly of plasmonic gold nanoparticles into smart plasmonic core-satellite nanostructures that allow for the dynamic and reversible tuning of the localised surface plasmon resonance using temperature. This smart system takes advantage of the thermoresponsive polymer linker that modulates the gap distance between the core and satellites in response to the temperature, resulting in the tuning of the surface plasmon coupling and resultant optical shift. It permits optical shifts over a wide wavelength range and reversible control of the optical properties by altering the temperature, which may allow these systems to become candidates for temperature sensitive nanosensors...
February 14, 2018: Nanoscale
Hongxia Li, Xu Yan, Shanpeng Qiao, Geyu Lu, Xingguang Su
Carbon dots (CDs) attract increasing interest in bioimaging and sensing recently. Herein, we present a simple synthetic strategy to prepare yellow-emission CDs (λem = 535 nm) by one-pot hydrothermal treatment of p-phenylenediamine and aspartic acid. The as-prepared CDs possess outstanding optical features, excellent biocompatibility and low cytotoxicity, especially for fluorescence cellular imaging. Interestingly, by combining the quenching and recognition ability of AgNPs with the optical capacity of CDs, a label-free strategy for specifically monitoring H2O2-generated biocatalytic processes was proposed, such as glucose oxidase-induced conversion of glucose, cholesterol oxidase-catalyzed oxidization of cholesterol, bi-enzyme of acetylcholinesterase and choline oxidase-mediated reaction of acetylcholine...
February 14, 2018: ACS Applied Materials & Interfaces
Thakshila Liyanage, Ashur Rael, Sidney Shaffer, Shozaf Zaidi, John V Goodpaster, Rajesh Sardar
Apart from high sensitivity and selectivity of surface-enhanced Raman scattering (SERS)-based trace explosive detection, efficient sampling of explosive residue from real world surfaces is very important for homeland security applications. Herein, we demonstrate an entirely new SERS nanosensor fabrication approach. The SERS nanosensor was prepared by self-assembling chemically synthesized gold triangular nanoprisms (Au TNPs), which we show display strong electromagnetic field enhancements at the sharp tips and edges, onto a pressure-sensitive flexible adhesive film...
February 12, 2018: Analyst
Shanyue Guan, Di Yang, Yangziwan Weng, Heng Lu, Xiangmin Meng, Xiaozhong Qu, Shuyun Zhou
In this work, a novel ruthenium complex loaded monolayer layered double hydroxide (LDH) (denoted as Ru(C-bpy)2 /mLDH) as supramolecular nanosensor is synthesized, which is greatly exclusive to the hypoxic tumor microenvironment. The Ru(C-bpy)2 /mLDH ultrathin sheet displays not only enhanced luminescence lifetime compared to the parent Ru(C-bpy)2 alone, but also improved oxygen responsibility under an excitation of 488 or 800 nm. Moreover, the Ru(C-bpy)2 /mLDH is possessed of two-photon fluorescence imaging ability under the 800 nm irradiation...
February 12, 2018: Advanced Healthcare Materials
Harpreet Kaur, Pushap Raj, Hemant Sharma, Meenakshi Verma, Narinder Singh, Navneet Kaur
Carbon Quantum Dots (CDs) owing to its unique photophysical properties have attracted immense consideration of the researchers in last decade to explore its applications in the fields of bio-imaging and sensing. In the present work, we have developed a novel CDs functionalized with Calix[4]arene derivative by hydrothermal route to detect biologically pertinent Zn2+ ions. Surface modification of CDs enhances fluorescence efficiency apart from introducing active surface sites broadening its sensor capabilities...
June 7, 2018: Analytica Chimica Acta
Jia-Huan Qu, Qingyi Wei, Da-Wen Sun
In the past ten years, as a novel and prospective nanomaterials, carbon dots have acquired tremendous attention for their unique optical and physicochemical properties, high compatibility and low cost, as well as great potential in sensing area. This review aims to present the current detecting principles based on carbon dots and other nano biological technologies, involving fluorescence quenching and recovery mechanisms. The synthetic and modificatory approaches in making carbon dots including top-down and bottom-up methods, as well as surface passivation and heteroatom doping ways are introduced...
February 8, 2018: Critical Reviews in Food Science and Nutrition
Alamzeb Khan, Hazem Dawoud, Tadeusz Malinski
Background: Clinical studies indicate that vitamin D3 improves circulation and may have beneficial effects in hypertension. This study uses nanomedical systems to investigate the role of 1,25-dihydroxy vitamin D3 in the preservation/restoration of endothelial function in an angiotensin II (Ang II) cellular model of hypertension. Methods: 1,25-dihydroxy vitamin D3-stimulated nitric oxide (NO) and peroxynitrite (ONOO-) concentrations were measured in situ with nanosensors (200-300 mm diameter with a detection limit of 1 nM) in human umbilical vein endothelial cells of African American (AA) and Caucasian American (CA) donors exposed to Ang II...
2018: International Journal of Nanomedicine
Quan Song, Yunsu Ma, Xu Wang, Tang Tang, Yueyue Song, Yujie Ma, Guanhong Xu, Fangdi Wei, Yao Cen, Qin Hu
In this work, a novel strategy for Zn2+ detection was established by using an "on-off-on" ratiometric fluorescent nanosensor with the help of ethylene diaminetetraacetic acid (EDTA), a common metal chelating agent. The simple and practical ratiometric fluorescent nanosensor was synthesized by covalently binding CdTe quantum dots (QDs) and carbon dots (CDs), possessing two emission peaks at 525 nm and 450 nm under a single wavelength excitation of 360 nm, respectively. The CdTe QDs served as the response signal label, and the CDs, having no response to the analytes, acted as the reference signal...
February 1, 2018: Journal of Colloid and Interface Science
Huan Yang, Yuwei Long, Hongxi Li, Shuang Pan, Hui Liu, Jidong Yang, Xiaoli Hu
In this work, the carbon dots (CDs) were synthesized by an one-pot portable hydrothermal method from sodium citrate and NH4HCO3. The obtained CDs were found to show high fluorescence quantum yield (31%), excitation-wavelength independence, outstanding water-soluble, excellent chemical and optical stability. Interestingly, it was discovered that sunset yellow (SY) was sensitive and effective in quenching the fluorescence of CDs. Based on this observation, CDs could be applied as a novel fluoescent probe for detection of SY...
February 1, 2018: Journal of Colloid and Interface Science
Jie Pang, Hailing Liu, Jian Li, Ting-Ting Zhai, Kang Wang, Xing-Hua Xia
Silver nanoparticles (AgNPs) have been widely used as photocatalyst and nanosensors. Observation of the spectroscopy of single AgNP greatly helps understanding the catalytic characteristic and morphology change of the AgNP during reactions. In the present study, AgNPs that physically adsorbed on indium tin oxide (ITO) conductive glass were electrochemically reduced and oxidized, and the plasmonic resonance Rayleigh scattering (PRRS) spectrum of individual AgNP was observed under a dark field microscopy (DFM) equipped with a spectrometer...
January 31, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Behrooz Shojaee Sadi, Mansour Bayat, Parviz Tajik, Seyed Jamal Hashemi
The specific immune-reaction between the anti-citrinin antibody immobilized on the surface of magnetic/silica core-shell (MSCS) and the citrinin-Rho123-BSA conjugate brings the Rho123 fluorophore as an acceptor and the QDs as a donor in close spatial proximity and causes FRET for occurring upon photo-excitation of the QDs. The novelties of this study include: (1) immobilization of the MSCS; (2) large amount of the immobilized QDs, and (3) immobilization of a large amount of Rho123 on the BSA macromolecule. Cd/Te QDs were synthesized by the simultaneous reduction of cadmium chloride and tellurium in the presence of sodium borohydride...
January 2018: Saudi Journal of Biological Sciences
Ignacio Fernández-Moncada, Iván Ruminot, Daniel Robles-Maldonado, Karin Alegría, Joachim W Deitmer, L Felipe Barros
Aerobic glycolysis is a phenomenon that in the long term contributes to synaptic formation and growth, is reduced by normal aging, and correlates with amyloid beta deposition. Aerobic glycolysis starts within seconds of neural activity and it is not obvious why energetic efficiency should be compromised precisely when energy demand is highest. Using genetically encoded FRET nanosensors and real-time oxygen measurements in culture and in hippocampal slices, we show here that astrocytes respond to physiological extracellular K+ with an acute rise in cytosolic ATP and a parallel inhibition of oxygen consumption, explained by glycolytic stimulation via the Na+-bicarbonate cotransporter NBCe1...
January 29, 2018: Proceedings of the National Academy of Sciences of the United States of America
Alsu Mukhametshina, Alexey Petrov, Svetlana Fedorenko, Konstantin Petrov, Irek Nizameev, Asiya Mustafina, Oleg Sinyashin
The present work introduces for the first time a nanoparticulate approach for ex vivo monitoring of acetylcholinesterase-catalyzed hydrolysis of endogenous acetylcholine released from nerve varicosities in mice atria. Amino-modified 20-nm size silica nanoparticles (SNs) doped by luminescent Tb(III) complexes were applied as the nanosensors. Their sensing capacity results from the decreased intensity of Tb(III)-centred luminescence due to the quenching effect of acetic acid derived from acetylcholinesterase-catalyzed hydrolysis of acetylcholine...
January 29, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
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