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gold nanoparticles

Joao Paulo Coelho, José Osío Barcina, Elena Junquera, Emilio Aicart, Gloria Tardajos, Sergio Gómez-Graña, Pablo Cruz-Gil, Cástor Salgado, Pablo Díaz-Núñez, Ovidio Peña-Rodríguez, Andrés Guerrero-Martínez
Amphiphilic nonionic ligands, synthesized with a fixed hydrophobic moiety formed by a thiolated alkyl chain and an aromatic ring, and with a hydrophilic tail composed of a variable number of oxyethylene units, were used to functionalize spherical gold nanoparticles (AuNPs) in water. Steady-state and time-resolved fluorescence measurements of the AuNPs in the presence of α-cyclodextrin (α-CD) revealed the formation of supramolecular complexes between the ligand and macrocycle at the surface of the nanocrystals...
March 16, 2018: Nanomaterials
Syeda Sabrina, Mykola Tasinkevych, Suzanne Ahmed, Allan M Brooks, Monica Olvera de la Cruz, Thomas E Mallouk, Kyle J M Bishop
The propulsion of micro- and nanoparticles using ultrasound is an attractive strategy for the remote manipulation of colloidal matter using biocompatible energy inputs. However, the physical mechanisms underlying acoustic propulsion are poorly understood, and our ability to transduce acoustic energy into different types of particle motions remains limited. Here, we show that the three-dimensional shape of a colloidal particle can be rationally engineered to direct desired particle motions powered by ultrasound...
March 16, 2018: ACS Nano
Maria J Gonzalez-Moa, Bieke Van Dorst, Ole Lagatie, Ann Verheyen, Lieven Stuyver, Marco A Biamonte
Three O. volvulus immunogenic peptide sequences recently discovered by peptide microarray were adapted to a lateral flow assay (LFA). The LFA employs gold nanoshells as novel high-contrast reporter nanoparticles and detects a serological response against the 3 peptides, found in OvOC9384, OvOC198, and OvOC5528, respectively. When tested on 118 sera from O. volvulus infected patients and 208 control sera, the LFA was 90, 63, and 98% sensitive for each peptide, respectively, and 99-100% specific vs. samples from healthy volunteers...
March 16, 2018: ACS Infectious Diseases
Iwona Sembratowicz, Katarzyna Ognik
Gold nanoparticles (AuNPs) are one of the most examined nanomaterials, but information about their immunogenic potential is still insufficient. Understanding interaction of AuNPs with immune system is essential in designing their safety and possibilities of biomedical applications. An experiment was conducted to determine immunotropic activity of gold nanocolloid (AuNPs) administered orally to chickens depending on dose and duration time. 162 birds were assigned to 9 experimental groups of 18 birds each. The control group (C) did not receive AuNPs...
May 2018: Journal of Trace Elements in Medicine and Biology
Stéphane Faucher, Samantha Soulé, Anne-Laure Bulteau, Joachim Allouche, Gaëtane Lespes
A method to determine total gold (Au) and/or silver (Ag) elemental concentrations from gold nanoparticles, Au-Ag nanoshells (NS) and silica coated Au-Ag nanoshells was developed, evaluated and validated. Samples were mineralized in a mixture of concentrated aqua regia and hydrofluoric acid at 65 °C for 4 h. Mineralized solutions were diluted and standard solutions were prepared in aqua regia 5%. ICP-MS analysis was performed with or without the use of a reaction cell (CRC). For the determination of elemental concentrations of nanopowders and test suspensions, the average recovery was 99 ± 2% and 101 ± 2% for gold and silver respectively...
May 2018: Journal of Trace Elements in Medicine and Biology
Ankita Jagannath Lakade, Kothandapani Sundar, Prathapkumar H Shetty
A new approach was developed for a simple and easy colorimetric detection assay to detect the use of calcium carbide in artificial ripening of fruits. Residues of arsenic on the fruit surface were used as an indicator for this. Use of calcium carbide in artificial ripening has been banned in many countries including India. In the present study, we have used a gold nanoparticle-based colorimetric detection method for determination of artificial ripening of fruits. ICP-MS analysis showed the presence of higher amounts of arsenic on fruits ripened using calcium carbide...
March 15, 2018: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
Marc Pretze, Andreas Hien, Matthias Raedle, Ralf Schirrmacher, Carmen Wängler, Björn Wängler
Gold nanoparticles (AuNPs) have widely been used for 70 years in cancer treatment, but only in the last 15 years the focus has been on specific AuNPs with homogeneous size and shape for various areas in science. They constitute a perfect platform for multi-functionalization and therefore enable the enhancement of target affinity. Here we report on the development of tumor specific AuNPs as diagnostic tools intended for the detection of prostate cancer via fluorescence imaging and positron emission tomography (PET)...
March 15, 2018: Bioconjugate Chemistry
Peng Chen, Xiaohu Liu, Garima Goyal, Nhung Thi Tran, James Chin Shing Ho, Yi Wang, Daniel Aili, Bo Liedberg
Localized surface plasmon resonance (LSPR) constitutes a versatile technique for biodetection exploiting the sensitivity of plasmonic nanostructures to small changes in refractive index. The optical shift in the LSPR band caused by molecular in-teractions in the vicinity of the nanostructures are typically < 5 nm and can readily be detected using a spectrophotometer. Widespread use of LSPR based sensors require cost effective devices and would benefit from sensing schemes that enables use of very simple spectrophotometers or even naked eye detection...
March 15, 2018: Analytical Chemistry
Jin-Wen Liu, Yu-Min Wang, Chong-Hua Zhang, Lu-Ying Duan, Zheng Li, Ru-Qin Yu, Jian-Hui Jiang
Unique physicochemical characteristics of graphitic carbon nitride (g-CN) nanosheets suit them a useful tool for two-photon fluorescence bioimaging. Current g-CN nanosheets based imaging probes typically use the "always-on" design strategies, which may suffer from increased fluorescence background and limited contrast. To advance corresponding applications, g-CN nanosheets based activatable two-photon fluorescence probes remain to be explored. For the first time, we developed an activatable two-photon fluorescence probe, constructed from a nanoassembly of g-CN nanosheets and hyaluronic acid (HA)-gold nanoparticles (HA-AuNPs), for detection and imaging of hyaluronidase (HAase) in cancer cells...
March 15, 2018: Analytical Chemistry
Tien D Tran, Mai T T Nguyen, Hoang V Le, Duc N Nguyen, Quang Duc Truong, Phong D Tran
An electrode made of Au nanoparticles, ca. 13 nm in diameter, displays outstanding catalytic activity for the hydrogen evolution reaction in water. At an overpotential of 200 mV it operates with a catalytic rate TOF of 0.3 s-1 , which is among the best performances ever achieved for a Pt-free H2 -evolving catalyst.
March 15, 2018: Chemical Communications: Chem Comm
Mengran Liu, Guoli Fan, Jiaying Yu, Lan Yang, Feng Li
Tuning the surface properties of supported metal catalysts is of vital importance for governing their catalytic performances in nanocatalysis. Here, we report highly dispersed nanometric gold nanoparticles (NPs) supported on Ni-Ti layered double hydroxides (NiTi-LDHs), which were employed in solvent-free and base-free selective oxidation of benzyl alcohol. A series of characterization techniques demonstrated that defect-rich NiTi-LDHs could efficiently stabilize Au NPs and decrease surface electron density of Au NPs...
March 15, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Jutaek Nam, Sejin Son, Lukasz J Ochyl, Rui Kuai, Anna Schwendeman, James J Moon
Photothermal therapy (PTT) is a promising cancer treatment modality, but PTT generally requires direct access to the source of light irradiation, thus precluding its utility against disseminated, metastatic tumors. Here, we demonstrate that PTT combined with chemotherapy can trigger potent anti-tumor immunity against disseminated tumors. Specifically, we have developed polydopamine-coated spiky gold nanoparticles as a new photothermal agent with extensive photothermal stability and efficiency. Strikingly, a single round of PTT combined with a sub-therapeutic dose of doxorubicin can elicit robust anti-tumor immune responses and eliminate local as well as untreated, distant tumors in >85% of animals bearing CT26 colon carcinoma...
March 14, 2018: Nature Communications
Inna M Yasinska, Giacomo Ceccone, Isaac Ojea-Jimenez, Jessica Ponti, Rohanah Hussain, Giuliano Siligardi, Steffen M Berger, Elizaveta Fasler-Kan, Marco Bardelli, Luca Varani, Walter Fiedler, Jasmin Wellbrock, Ulrike Raap, Bernhard F Gibbs, Luigi Calzolai, Vadim V Sumbayev
In this study we used 5 nm gold nanoparticles as delivery platforms to target cancer cells expressing the immune receptor Tim-3 using single chain antibodies. Gold surfaces were also covered with the cytotoxic drug rapamycin which was immobilised using a glutathione linker. These nanoconjugates allowed highly specific and efficient delivery of cytotoxic rapamycin into human malignant blood cells.
March 14, 2018: Nanoscale
Mahmoud Nasrollahzadeh, Mohaddeseh Sajjadi, Fatemeh Ghorbannezhad, S Mohammad Sajadi
A3 coupling is one of the few transition-metal catalyzed carbon-carbon bond forming reactions that have been established as a most direct, efficient and atom-economical synthetic approach to afford propargylamine derivatives using various catalysts. A large number of nanosized heterogeneous catalysts for three-component coupling reactions between an aldehyde, an amine, and a terminal alkyne have been popularly introduced as an A3 coupling in the last decade. The coupling product has found a broad application as a key intermediate for a variety of heterocyclic useful compounds and numerous biologically active molecules such as β-lactams, conformationally restricted peptides, isosteres, herbicides, fungicides, indolizines, pyrroles, quinolines and therapeutic drug molecules...
March 14, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Shu Fen Tan, Sanoj Raj, Geeta Bisht, Harshini V Annadata, Christian A Nijhuis, Petr Král, Utkur Mirsaidov
Self-assembly of solvated nanoparticles (NPs) is governed by numerous competing interactions. However, relatively little is known about the time-dependent mechanisms through which these interactions enable and guide the nanoparticle self-assembly process. Here, using in situ transmission electron microscopy imaging combined with atomistic modeling, it is shown that the forces governing the self-assembly of hydrophobic nanoparticles change with the nanoparticle shapes. By comparing how gold nanospheres, nanocubes, nanorods, and nanobipyramids assemble, it is shown that the strength of the hydrophobic interactions depends on the overlap of the hydrophobic regions of the interacting nanoparticle surfaces determined by the nanoparticle shapes...
March 14, 2018: Advanced Materials
George W Pratt, Andy Fan, Bissrat Melakeberhan, Catherine M Klapperich
Proper management of an HIV infection requires that a patient be at least 80-95% adherent to a prescribed drug regimen to avoid poor health outcomes and the development of drug-resistant HIV strains. Clinicians generally monitor adherence habits indirectly through patient self-reporting, pill counting, and electronic drug monitoring. While direct measurement of patient samples like urine for monitoring drug levels is possible, it requires specialized equipment and training that is not readily available in resource-limited settings where the need is greatest...
August 9, 2018: Analytica Chimica Acta
Md Zakir Hossain, Susan P McCormick, Chris M Maragos
A sensitive, rapid, and reproducible imaging surface plasmon resonance (iSPR) biosensor assay was developed to detect T-2 toxin and T-2 toxin-3-glucoside (T2-G) in wheat. In this competitive assay, an amplification strategy was used after conjugating a secondary antibody (Ab₂) with gold nanoparticles. Wheat samples were extracted with a methanol/water mixture (80:20 v/v), then diluted with an equal volume of primary antibody (Ab₁) for analysis. Matrix-matched calibration curves were prepared to determine T-2 toxin and T2-G...
March 10, 2018: Toxins
Smruti R Sahoo, P V R K Ramacharyulu, Shyue-Chu Ke
No abstract text is available yet for this article.
March 13, 2018: Analytical Chemistry
Marwa M Azab, Rédha Cherif, Aryanne L Finnie, Maha M Abou El-Alamin, Maha A Sultan, Alastair W Wark
Gold nanorods (NRs) have attracted a great deal of interest for a variety of biomedical and sensing applications. However, developing robust methods for biofunctionalizing NRs has continued to be challenging, especially for NR-DNA conjugates. This is due to the presence of cetyltrimethylammonium bromide (CTAB), which plays an essential role in controlling the anisotropic particle growth. In this article, we systematically explore the growth of a polydopamine (PDA) layer on a range of NR surfaces, comparing different polyelectrolyte and alkanethiol coatings as well as direct CTAB displacement...
March 13, 2018: Analyst
Heerak Chugh, Damini Sood, Ishita Chandra, Vartika Tomar, Gagan Dhawan, Ramesh Chandra
Development of nanoparticles (NPs) as a part of cancer therapeutics has given rise to a new field of research - cancer nanomedicine. In comparison to traditional anti-cancer drugs, NPs provide a targeted approach which prevents undesirable effects. In this communication, we have reviewed the role of gold and silver NPs (AgNPs) in the cancer nanomedicine. The preparation of gold NPs (AuNPs) and AgNPs can be grouped into three categories - physical, chemical and biological. Among the three approaches, the biological approach is growing and receiving more attention due to its safe and effective production...
March 13, 2018: Artificial Cells, Nanomedicine, and Biotechnology
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