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Paula García Calavia, Gordon Bruce, Lluïsa Pérez-García, David A Russell
Gold nanoparticles (AuNPs) have been extensively studied within biomedicine due to their biocompatibility and low toxicity. In particular, AuNPs have been widely used to deliver photosensitiser agents for photodynamic therapy (PDT) of cancer. Here we review the state-of-the-art for the functionalisation of the gold nanoparticle surface with both photosensitisers and targeting ligands for the active targeting of cancer cell surface receptors. From the initial use of the AuNPs as a simple carrier of the photosensitiser for PDT, the field has significantly advanced to include: the use of PEGylated modification to provide aqueous compatibility and stealth properties for in vivo use; gold metal-surface enhanced singlet oxygen generation; functionalisation of the AuNP surface with biological ligands to specifically target over-expressed receptors on the surface of cancer cells and; the creation of nanorods and nanostars to enable combined PDT and photothermal therapies...
August 17, 2018: Photochemical & Photobiological Sciences
Sunil Kumar Surapaneni, Shafiya Bashir, Kulbhushan Tikoo
Gold nanoparticles (AuNPs) are used enormously in different cancers but very little is known regarding their molecular mechanism and surface charge role in the process of cell death. Here, we elucidate the molecular mechanism by which differentially charged AuNPs induce cytotoxicity in triple negative breast cancer (TNBC) cells. Cytotoxicity assay revealed that both negatively charged (citrate-capped) and positively charged (cysteamine-capped) AuNPs induced cell-death in a dose-dependent manner. We provide first evidence that AuNPs-induced oxidative stress alters Wnt signalling pathway in MDA-MB-231 and MDA-MB-468 cells...
August 16, 2018: Scientific Reports
Tanya Hutter, Stephen R Elliott, Sumeet Mahajan
Enhancement of sub-wavelength optical fields using sub-micron plasmonic probes has found many applications in chemical, material, biological and medical sciences. The enhancement is via localised surface-plasmon resonance (LSPR) which enables the highly sensitive vibrational-spectroscopy technique of surface-enhanced Raman scattering (SERS). Combining SERS with optical fibres can allow the monitoring of biochemical reactions in situ with high resolution. Here, we study the electromagnetic-field enhancement of a tapered optical fibre-tip coated with gold nanoparticles (AuNPs) using finite-element simulations...
June 11, 2018: Optics Express
Hwa Kyung Sung, Eunhye Jo, Eunjeong Kim, Sun-Kyoung Yoo, Jae-Woo Lee, Pil-Je Kim, Younghun Kim, Ig-Chun Eom
With the increase in the application of nano-consumer products containing engineered nanoparticles (NPs), the unintended environmental exposure to NPs has been inevitable. Because of the bioaccumulation of NPs, concern about their potential cytotoxicity to aquatic organisms is also growing. Although measuring tools for analyzing particle size and/or concentration of NPs in intracellular uptake of tissues have been well developed, a simultaneous analysis of the two characteristics is difficult. The objective of this study was to use single particle-inductively coupled plasma-mass spectrometry (sp-ICP-MS) to measure the bioaccumulation and particle size changes of NPs exposed to zebrafish (Danio rerio) for 7 days...
October 2018: Chemosphere
Ranganathan Velu, Maria C DeRosa
Nano-aptamer probes were prepared and used in lateral flow colorimetric assays for the detection of Ochratoxin A (OTA). In this study, two approaches were examined using 5'-biotin-modified OTA aptamers and silver or gold nanoparticles (AgNP or AuNP). The first method used an "adsorption-desorption" approach wherein aptamers were adsorbed onto the metal nanoparticle surface. Upon the addition of OTA, the aptamer binds specifically to the target, releasing the NPs. The above solutions were applied on a lateral flow assay (LFA) and a detection limit of 6...
August 16, 2018: Analyst
Zheng-Jun Xie, Xian-Yu Bao, Chi-Fang Peng
A new colorimetric detection of methylmercury (CH₃Hg⁺) was developed, which was based on the surface deposition of Hg enhancing the catalytic activity of gold nanoparticles (AuNPs). The AuNPs were functionalized with a specific DNA strand (HT7 ) recognizing CH₃Hg⁺, which was used to capture and separate CH₃Hg⁺ by centrifugation. It was found that the CH₃Hg⁺ reduction resulted in the deposition of Hg onto the surface of AuNPs. As a result, the catalytic activity of the AuNPs toward the chromogenic reaction of 3,3,5,5-tetramethylbenzidine (TMB)-H₂O₂ was remarkably enhanced...
August 15, 2018: Sensors
Lotte M P Vermeulen, Juan C Fraire, Laurens Raes, Ellen De Meester, Sarah De Keulenaer, Filip Van Nieuwerburgh, Stefaan De Smedt, Katrien Remaut, Kevin Braeckmans
Plasmonic nanoparticles for drug delivery have attracted increasing interest over the last few years. Their localized surface plasmon resonance causes photothermal effects on laser irradiation, which allows for delivering drugs in a spatio-temporally controlled manner. Here, we explore the use of gold nanoparticles (AuNP) as carriers for pDNA in combination with pulsed laser irradiation to induce endosomal escape, which is currently considered to be one of the major bottlenecks in macromolecular drug delivery on the intracellular level...
August 14, 2018: International Journal of Molecular Sciences
Michaela Tvrdonova, Marcela Vlcnovska, Lucie Pompeiano Vanickova, Viktor Kanicky, Vojtech Adam, Lena Ascher, Norbert Jakubowski, Marketa Vaculovicova, Tomas Vaculovic
In this paper, we describe the labelling of antibodies by gold nanoparticles (AuNPs) with diameters of 10 and 60 nm with detection by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Additionally, the AuNPs labelling strategy is compared with commercially available labelling reagents based on MeCAT (metal coded affinity tagging). Proof of principle experiments based on dot blot experiments were performed. The two labelling methods investigated were compared by sensitivity and limit of detection (LOD)...
August 14, 2018: Analytical and Bioanalytical Chemistry
Cody D Sacks, Katherine A Stumpo
New applications for gold nanoparticles (AuNPs) in Laser Desorption Ionization Mass Spectrometry (LDI-MS) are presented here. This work expands on previous biomolecule studies and introduces carbohydrates, steroids, bile acids, and other small molecules as a focus. Broad trends in ionization are observed and specifically of interest are new species that have not previously been reported from AuNPs (e.g., [M+Au]+ ). Interesting fragmentation effects have been observed for diphenhydramine, including similarity to Electron Impact mass spectra and possible radical driven reactions, providing insight into the mechanism of ionization when using AuNPs...
August 14, 2018: Journal of Mass Spectrometry: JMS
André Filipe Ferreira, Michela Comune, Akhilesh Rai, Lino Ferreira, Pedro Nuno Simões
LL37 is a cathelicidin-derived AMP with a broad spectrum of antimicrobial activity and wound healing potential. The enhancement of these characteristics were recently demonstrated for a cysteine (CYS) modified cathelicidin-derived (LL37-SH) conjugated with gold nanoparticles (AuNP). Considering the potential of this peptide, we hereby report a computational study in which well-tempered metadynamics was applied to unveil the interaction of LL37-SH and LL37 with a AuNP with atomistic detail. A structural analysis combined with the free energy surface (FES) characterization allowed to assess the role of CYS residue during the formation of the conjugate, as well as to understand how the AuNP improves the antimicrobial activity of the peptide...
August 14, 2018: Journal of Physical Chemistry. B
Mengke Wang, Dandan Su, Guannan Wang, Xingguang Su
In this work, a facile, label-free, and sensitive fluorometric strategy for detection of trypsin and its inhibitor was established on the basis of the fluorescence resonance energy transfer (FRET) between mercaptoundecanoic acid functionalized gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) via protamine as a bridge. Protamine can trigger the aggregation of AuNPs and link AuNCs with aggregated AuNPs through electrostatic interaction. Compared with monodisperse AuNPs, the UV-vis absorption band of aggregated AuNPs overlapped considerably with the emission spectrum of AuNCs...
August 13, 2018: Analytical and Bioanalytical Chemistry
Yuning Wang, Ruijun Du, Liang Qiao, Baohong Liu
A signal amplification protocol based on mass spectrometry (MS) was developed to profile simultaneously multiple biomarkers from a single cell using various mass label (ML)-modified Au nanoparticles (AuNPs). The strategy with ultrahigh sensitivity and specificity has potential prospects in the deep exploration of molecular and cellular characterization.
August 13, 2018: Chemical Communications: Chem Comm
Timothy Robson, Deepan S H Shah, Alexandra S Solovyova, Jeremy H Lakey
Functional protein-gold nanoparticle (AuNP) conjugates have a wide variety of applications including biosensing and drug delivery. Correct protein orientation, which is important to maintain functionality on the nanoparticle surface, can be difficult to achieve in practice, and dedicated protein scaffolds have been used on planar gold surfaces to drive the self-assembly of oriented protein arrays. Here we use the transmembrane domain of Escherichia coli outer membrane protein A (OmpATM ) to create protein-AuNP conjugates...
July 27, 2018: ACS applied nano materials
Zhengzong Wu, Deyun He, Enbo Xu, Aiquan Jiao, Muhammad Farhan Jahangir Chughtai, Zhengyu Jin
A simple, rapid and economic lateral flow immunochromatographic assay (LFICA) was designed for ultrasensitive detection of β-conglutin. Instead of antibodies and gold nanoparticles (AuNPs) used in conventional LFICA, a cognate aptamer duo, binding to β-conglutin and Fe3 O4 @Au core-shell nanoparticles, was applied in this study. An enzyme signal amplification strategy was used to enhance sensitivity. In addition, a new magnetic enrichment strategy was employed to further enhance sensitivity of the assay, slowing down movement of the capture probe (i...
December 15, 2018: Food Chemistry
Jing Wang, Haigang Li, Tingting Li, Liansheng Ling
A one-step, one-tube colorimetric assay is described for the detection of bacterial double-stranded DNA (dsDNA). It utilizes a G-quadruplex DNAzyme produced by an asymmetric polymerase chain reaction (As-PCR) that catalyzes the oxidation of cysteine to form cystine. This results in the formation of oligonucleotide-modified gold nanoparticles via triplex formation, and eventually in a color change from red to blue that occurs within about 10 mins. This can be measured by ratiometric colorimetric (at 525 and 600 nm)...
August 11, 2018: Mikrochimica Acta
Huili Shao, Han Lin, Jing Lu, Yufang Hu, Sui Wang, Youju Huang, Zhiyong Guo
Here, a novel Faraday cage-type electrochemiluminescence (ECL) biosensor was presented for simultaneous determination of miRNA-141 and miRNA-21 based on the potential-resolved strategy. In this work, capture units were prepared by immobilizing hairpin DNA1 (HP1) and hairpin DNA2 (HP2) on Fe3 O4 @Au nanocomposites, while g-C3 N4 @AuNPs nanocomposites labelled by signal DNA1 (sDNA1) and ruthenium-based metal organic framework (Ru-MOF) nanosheets labelled by signal DNA2 (sDNA2) were used as signal units. In this proposed biosensor, signal units g-C3 N4 @AuNPs-sDNA1 and Ru-MOF-sDNA2 could exhibit two strong and stable ECL emissions at - 1...
July 31, 2018: Biosensors & Bioelectronics
Ying Li, Fengting Chen, Zhenzhu Luan, Xiaoru Zhang
Novel cathodic photoelectrochemical (PEC) aptasensors for sensitive and selective determination of thrombin and Pb2+ were developed based on a new dual-signal amplification strategy. The presence of gold nanoparticles (AuNPs) could quench the PEC signal of bismuth oxyiodide (BiOI). At the same time, the redox moiety G-quadruplex/hemin or ferrocene (Fc) was found to enhance the PEC signal of BiOI. So, in the presence of thrombin or Pb2+ , the interaction between target and the aptamer resulted in the releasement of the AuNPs, as well as shorter distance between the redox moiety and the electrode surface...
July 31, 2018: Biosensors & Bioelectronics
Quang Huy Quach, Swee Kim Ang, Jang-Hann Justin Chu, James Chen Yong Kah
Dengue results in substantial human morbidity and significant socio-economic impacts, but a specific dengue therapeutic is not available. The currently available dengue vaccine has low efficacy and high rate of adverse effects, necessitating different strategies for the development of a safer and more efficient vaccine against dengue virus. We describe here a hybrid combination of different-sized gold nanoparticles (AuNPs) and domain III of envelope glycoprotein derived from serotype 2 of dengue virus (EDIII) as dengue subunit vaccine...
August 9, 2018: Acta Biomaterialia
Shib Shankar Singha, Suchanda Mondal, Tara Shankar Bhattacharya, Laboni Das, Kamalika Sen, Biswarup Satpati, Kaustuv Das, Achintya Singha
Fabrication of Molybdenum disulfide (MoS2 ) nanostructures and surface functionalization with noble metal nano particles is an emerging field of research as it has potential applications in electronic devices and chemical sensing. Here we report application of gold nanoparticles (AuNPs) decorated MoS2 nanoflowers (Au-MoS2 NFs) as an efficient bio-sensor. MoS2 NFs, synthesized using green synthesis process, are further functionalized with AuNPs to tune their physical properties and make them more appropriate for biological applications...
July 30, 2018: Biosensors & Bioelectronics
Zhi Cao, Samson B Zacate, Xiaodong Sun, Jinjia Liu, Elizabeth M Hale, William P Carson, Sam B Tyndall, Jun Xu, Xingwu Liu, Xingchen Liu, Chang Song, Jheng-Hua Luo, Mu-Jeng Cheng, Xiaodong Wen, Wei Liu
We report the capped chelating organic molecules as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110-fold enhancement, compared to the oleylamine-coated AuNP, in current density for electrochemical reduction of CO2 to CO in water at an overpotential of 340 mV with Faradaic efficiencies (FEs) of 93%. These catalysts also show excellent stability without deactivation, <5% productivity loss, within 72 hours of electrolysis...
August 10, 2018: Angewandte Chemie
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