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https://www.readbyqxmd.com/read/30553146/surface-plasmon-resonance-of-gold-nanoparticles-as-a-colorimetric-sensor-for-indirect-detection-of-cefixime
#1
Zeinab Masoudyfar, Shahla Elhami
This study reports a colorimetric sensor with excellent sensitivity to detect Cefixime base on gold nanoparticles. Cefixime is an antibiotic which has a wide range of applications in medicine. Cefixime did not change the surface plasmon resonance bond in gold nanoparticles solution; therefore, there was no change in the color solution of gold nanoparticles. The presence of Alizarin Red S in the system was necessary for the degradation of Cefixime, resulting in the aggregation of gold nanoparticles and a color change from red to blue...
December 4, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/30551875/quantitative-analyses-of-amount-and-localization-of-radiosensitizer-gold-nanoparticles-interacting-with-cancer-cells-to-optimize-radiation-therapy
#2
Keiichiro Hatoyama, Narufumi Kitamura, Mayumi Takano-Kasuya, Masayuki Tokunaga, Takahiro Oikawa, Mineto Ohta, Yoh Hamada, Hiroshi Tada, Yoshio Kobayashi, Takashi Kamei, Kohsuke Gonda
Previous studies showed that gold nanoparticles (AuNPs) are useful radiosensitizers which optimize radiation therapy under low-dose radiation. However, the mechanisms of AuNP radiosensitization, including the amount and localization of the AuNPs interacting with cancer cells, has not yet been quantified. To answer these questions, we prepared AuNPs conjugated with anti-human epidermal growth factor receptor type 2 (HER2) antibody via polyethylene glycol (PEG) chains (AuNP-PEG-HER2ab). AuNP-PEG-HER2ab specifically bound to the HER2-expressing cancer cells and entered the cells via endocytosis...
December 11, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/30551611/carbon-quantum-dots-prepared-with-chitosan-for-synthesis-of-cqds-aunps-for-iodine-ions-detection
#3
Juanjuan Song, Li Zhao, Yesheng Wang, Yun Xue, Yujia Deng, Xihui Zhao, Qun Li
Water-soluble and reductive carbon quantum dots (CQDs) were fabricated by the hydrothermal carbonization of chitosan. Acting as a reducing agent and stabilizer, the as-prepared CQDs were further used to synthesize gold nanoparticles (AuNPs). This synthetic process was carried out in aqueous solution, which was absolutely "green". Furthermore, the CQDs/AuNPs composite was used to detect iodine ions by the colorimetric method. A color change from pink to colorless was observed with the constant addition of I- ions, accompanied by a decrease in the absorbance of the CQDs/AuNPs composite...
December 13, 2018: Nanomaterials
https://www.readbyqxmd.com/read/30547579/dual-wavelength-ratiometric-electrochemiluminescence-immunosensor-for-cardiac-troponin-i-detection
#4
Jing Ye, Liping Zhu, Mengxia Yan, Qiuju Zhu, Qingqing Lu, Jianshe Huang, Hua Cui, Xiurong Yang
Ratiometric electrochemiluminescence (ECL) has attracted special focus in biological analysis field because it could eliminate the environmental interference to gain precise measurement. Herein, a dual-wavelength ratiometric ECL biosensor was designed for detection of cardiac troponin I (cTnI), where (4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium(II) (Ru(dcbpy)32+) and Au nanoparticles loaded graphene oxide/polyethyleneimine (GPRu-Au) nanomaterial acts as an acceptor, and Au nanoparticles modified graphitic phase carbon nitride nanosheets composite (Au-CNN) acts as donor...
December 14, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/30547173/aunp-peptide-probe-for-caspase-3-detection-in-living-cells-by-sers
#5
Cuilian Zhao, Lihong Qiu, Peng Lv, Ailing Han, Guozhen Fang, Jifeng Liu, Shuo Wang
Colloidal nanoparticles can be used as surface-enhanced Raman scattering (SERS) substrates because the very close spacing between particles existing in these colloidal systems is beneficial for the generation of extremely strong and highly spatially localized electric field enhancements. Herein, a caspase-3-specified peptide was used as a molecular cross-linker to engineer gold nanoparticle (AuNP) junctions in a controllable manner. The peptide was designed with a sequence of CCALNNPFFDVED (Cys-Cys-Ala-Leu-Asn-Asn-Pro-Phe-Phe-Asp-Val-Glu-Asp) or CCALNNKYDDVED (Cys-Cys-Ala-Leu-Asn-Asn-Lys-Tyr-Asp-Asp-Val-Glu-Asp), where the CALNN (Cys-Ala-Leu-Asn-Asn) fragment helps to stabilize AuNP suspension in aqueous media and the sequence of DVED (Asp-Glu-Val-Asp) can be cleaved by caspase-3...
December 14, 2018: Analyst
https://www.readbyqxmd.com/read/30542691/an-aptamer-based-voltammetric-biosensor-for-endotoxins-using-a-functionalized-graphene-and-molybdenum-disulfide-composite-as-a-new-nanocarrier
#6
Yonghua Yuan, Linlin Li, Min Zhao, Jing Zhou, Zhihui Chen, Lijuan Bai
Lipopolysaccharides (LPS), known as endotoxins, can cause a strong inflammatory response and lead to multiple organ failure in severe cases. This work reports a simple label-free voltammetric aptasensor for highly sensitive determination of LPS using a polyethyleneimine (PEI) functionalized reduced graphene oxide (rGO) and molybdenum disulfide (MoS2) composite (PEI-rGO-MoS2) as a new nanocarrier for electroactive toluidine blue (TB). The PEI-rGO-MoS2 nanocomposite with high electrical conductivity and large specific surface area can greatly increase the loading of TB and facilitate electron transfer from TB to an electrode...
December 13, 2018: Analyst
https://www.readbyqxmd.com/read/30540971/photothermally-controlled-drug-release-system-with-high-dose-loading-for-synergistic-chemo-photothermal-therapy-of-multidrug-resistance-cancer
#7
Xiaoxia Wu, Jing Liu, Lingyan Yang, Fu Wang
Chemotherapy is an important first-line strategy for tumor therapy in cancer treatment, but multidrug resistance (MDR) is a major problem that reduces the efficacy of chemotherapeutics. Herein, we report a novel photothermally controlled intelligent drug release system (AuNP@mSiO2 -DOX-FA) with a large amount of drugs loading for synergistic chemo-photothermal therapy of MDR in breast cancer. The nanoplatform utilized gold nanoparticles as a hyperthermia core, and large-mesoporous silica as a shell for doxorubicin (DOX) loading...
December 5, 2018: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/30538244/bioconjugation-strategy-for-cell-surface-labelling-with-gold-nanostructures-designed-for-highly-localized-ph-measurement
#8
Leonardo Puppulin, Shigekuni Hosogi, Hongxin Sun, Kazuhiko Matsuo, Toshio Inui, Yasuaki Kumamoto, Toshinobu Suzaki, Hideo Tanaka, Yoshinori Marunaka
Regulation of intracellular pH is critically important for many cellular functions. The quantification of proton extrusion in different types of cells and physiological conditions is pivotal to fully elucidate the mechanisms of pH homeostasis. Here we show the use of gold nanoparticles (AuNP) to create a high spatial resolution sensor for measuring extracellular pH in proximity of the cell membrane. We test the sensor on HepG2 liver cancer cells and MKN28 gastric cancer cells before and after inhibition of Na+ /H+ exchanger...
December 11, 2018: Nature Communications
https://www.readbyqxmd.com/read/30536733/a-versatile-dynamic-light-scattering-strategy-for-the-sensitive-detection-of-plant-micrornas-based-on-click-chemistry-amplified-aggregation-of-gold-nanoparticles
#9
Xiaohui Lu, Wenjiao Fan, Qinya Feng, Yan Qi, Chenghui Liu, Zhengping Li
Plant microRNAs (miRNAs) are naturally 2'-O-methylated at the 3'-terminal, so they cannot be efficiently detected by traditional target-triggered polymerization reactions. Herein, a simple but robust enzyme-free sensing strategy is developed for plant miRNA analysis by using dynamic light scattering (DLS) technique to monitor the click chemical ligation-amplified crosslinking of gold nanoparticles (AuNPs). Combining the enzyme-free cycling chemical ligation-mediated signal amplification, and the intrinsic outstanding ability of DLS for discriminating the extremely low level of particle aggregation in a large pool of monodisperse AuNPs, high sensitivity is achieved and as low as 78...
December 7, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/30535866/a-phenylboronate-based-sers-nanoprobe-for-detection-and-imaging-of-intracellular-peroxynitrite
#10
Hua-Ying Chen, Dan Guo, Zhen-Fei Gan, Lei Jiang, Shuai Chang, Da-Wei Li
A surface-enhanced Raman scattering (SERS) based nanoprobe was developed for detection and imaging of endogenous peroxynitrite in living cells. The probe was fabricated by assembling 3-mercaptophenylboronic acid pinacol ester onto the surface of gold nanoparticles (AuNPs). The detection of peroxynitrite is accomplished via measurement of the changes in the SERS spectra (at 882 cm-1 ) that are caused by the reaction between probe and peroxynitrite. The probe has a fast response (<30 s), a 0.4 μM lower detection limit and a wide linearity range from 5...
December 10, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/30535761/a-colorimetric-mercury-ii-assay-based-on-the-hg-ii-stimulated-peroxidase-mimicking-activity-of-a-nanocomposite-prepared-from-graphitic-carbon-nitride-and-gold-nanoparticles
#11
Yi-Wei Wang, Qiao Liu, Lixing Wang, Shurong Tang, Huang-Hao Yang, Hongbo Song
A one-step reduction method was used for the preparation of stable graphitic carbon nitride-gold nanoparticles (g-C3 N4 -Au) nanocomposites from ultrathin g-C3 N4 nanosheets and chloroauric acid by using NaBH4 as a reducing agent under ultrasonication. The nanocomposites were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis absorption and fluorescence spectroscopy etc. The results revealed that the gold nanoparticles (AuNPs) are uniformly formed on the g-C3 N4 nanosheets...
December 10, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/30535591/electrochemical-sandwich-immunoassay-for-insulin-detection-based-on-the-use-of-gold-nanoparticle-modified-mos-2-nanosheets-and-the-hybridization-chain-reaction
#12
Huidan Sun, Shaoyan Wu, Xiaoyan Zhou, Min Zhao, Haiping Wu, Rong Luo, Shijia Ding
A sandwich-type of electrochemical immunoassay is described for the determination of insulin. It is based on the use of a glassy carbon electrode that was modified with MoS2 nanosheets decorated with gold nanoparticles (AuNPs) to immobilize a large amount of first antibody (Ab1 ). Following exposure to insulin, secondary antibody (Ab2 ) that was cross-linked to a DNA initiator strand (T0 ) to form an Ab2 @T0 conjugate was added to undergo a sandwich immunoreaction. Subsequently, the long dsDNA concatemer was formed by a hybridization chain reaction between Ab2 @T0 and auxiliary probes (H1 , H2 )...
December 7, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/30533853/complete-genome-sequence-of-enterobacter-xiangfangensis-pb204-a-south-african-strain-capable-of-synthesizing-gold-nanoparticles
#13
Nicholas Ryan Ho, Kulsum Kondiah, Pieter De Maayer
Enterobacter xiangfangensis Pb204, isolated from acid mine decant from a uranium mine, produces a wide variety of gold nanoparticles (AuNPs), ranging from large triangular plates to small spherical AuNPs. The complete genome sequence of this isolate incorporates an integrative and conjugative element which may be pivotal to AuNP synthesis.
December 2018: Microbiology resource announcements
https://www.readbyqxmd.com/read/30529166/differences-in-uptake-of-14-nm-peg-liganded-gold-nanoparticles-into-beas-2b-cells-is-dependent-on-their-functional-groups
#14
Melissa Vetten, Mary Gulumian
Physico-chemical characteristics of nanoparticles have been shown to alter the uptake and toxicity of nanoparticles. This study investigated the uptake of six gold nanoparticles (AuNPs) into the human bronchial epithelial cell line BEAS-2B. The AuNPs studied included colloidal citrate-stabilised AuNPs of 14 nm in diameter; and 14 nm AuNPs conjugated to functional groups via polyethylene glycol (PEG), namely hydroxyl-PEG (POH), carboxyl-PEG (PCOOH), biotin-PEG (PBtn), nitrilotriacetic acid-PEG (PNTA), and azide-PEG (PAZ)...
December 5, 2018: Toxicology and Applied Pharmacology
https://www.readbyqxmd.com/read/30527446/single-nanoparticle-tracking-with-angstrom-localization-precision-and-microsecond-time-resolution
#15
Jun Ando, Akihiko Nakamura, Akasit Visootsat, Mayuko Yamamoto, Chihong Song, Kazuyoshi Murata, Ryota Iino
Gold nanoparticles (AuNPs) have been used as a contrast agent for optical imaging of various single biomolecules. Because AuNPs have high scattering efficiency without photobleaching, biomolecular dynamics have been observed with nanometer localization precision and sub-millisecond time resolution. To understand the working principle of biomolecular motors in greater detail, further improvement of the localization precision and time resolution is necessary. Here, we investigated the lower limit of localization precision achievable with AuNPs and the fundamental law, which determines the localization precision...
November 17, 2018: Biophysical Journal
https://www.readbyqxmd.com/read/30525653/precisely-self-assembly-and-controlled-catalysis-of-thermoresponsive-core-satellite-multicomponent-hybrid-nanoparticles
#16
Jia Tian, Baoxuan Huang, Weian Zhang
The construction of multicomponent hybrid nanomaterials with well-controlled architecture, especially bearing an ordered homogeneity and distribution of the subunits with tunable functions, is a key challenge in chemistry and material science. Herein, we reported a versatile and novel strategy to fabricate core-satellite multicomponent nanostructures with tunable interparticle distances and catalysis properties by the combination of surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization and self-assembly...
December 10, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/30525495/real-time-monitoring-of-ligand-exchange-kinetics-on-gold-nanoparticle-surfaces-enabled-by-hot-spot-normalized-surface-enhanced-raman-scattering
#17
Haoran Wei, Weinan Leng, Junyeob Song, Chang Liu, Marjorie Willner, Qishen Huang, Wei Zhou, Peter J Vikesland
Nanoparticle surface coatings dictate their fate, transport, and bioavailability. We used a gold nanoparticle-bacterial cellulose substrate and "hot spot"-normalized surface-enhanced Raman scattering (HSNSERS) to achieve in situ and real-time monitoring of ligand exchange reactions on the gold surface. This approach enables semi-quantitative determination of citrate surface coverage. Following exposure of the citrate-coated nanoparticles to a suite of guest ligands (thiolates, amines, carboxylates, inorganic ions, and proteins), the guest ligand signal exhibited first-order growth kinetics, while the desorption mediated decay of the citrate signal followed a first-order model...
December 10, 2018: Environmental Science & Technology
https://www.readbyqxmd.com/read/30525481/nanopillar-assisted-sers-chromatography
#18
Onur Durucan, Kaiyu Wu, Marlitt Viehrig, Tomas Rindzevicius, Anja Boisen
Practical implementation of SERS sensing is hindered by complexity of real-life samples, which often requires long and costly pretreatment and purification. Here, we present a novel nanopillar-assisted SERS chromatography (NPC-SERS) method for simultaneous quantitation of target molecules and analysis of complex, multicomponent fluids, e.g. human urine spiked with a model drug paracetamol (PAR). Gold-coated silicon nanopillar (AuNP) SERS substrates and a centrifugal microfluidic platform are tactfully combined, which allows (i) a precise and fully automated sample manipulation, and (ii) spatial separation of different molecular species on the AuNP substrate...
December 11, 2018: ACS Sensors
https://www.readbyqxmd.com/read/30523846/new-strategy-to-obtain-high-surface-area-anatase-nanotube-aunp-photocatalyst
#19
Andressa da Cruz Schneid, Antonio Bauer Quevedo, Marcelo Barbalho Pereira, Pedro F Araújo, Noelia Franco, Giovanna Machado, Celso Camilo Moro, Eliana Weber de Menezes, Tania Maria Haas Costa, Edilson Valmir Benvenutti
Anatase nanotubes with high surface area (ca. 350 m2•g-1), containing gold nanoparticles, were successfully obtained from trititanate nanotubes, prepared by a template-free hydrothermal method, and calcined at 450 °C. The high surface area and tubular morphology were attained due to the presence of ionic silsesquioxane, which acts as anti-sintering agent for titania during calcination process, by forming a thin silica coating between anatase nanotubes. Additionally, the ionic silsesquioxane also acts as stabilizing and adhesion agent for gold nanoparticles on the surface of anatase nanotubes...
November 16, 2018: Nanotechnology
https://www.readbyqxmd.com/read/30521919/polyethylene-glycol-decorated-doxorubicin-carboxymethyl-chitosan-gold-nanocomplex-for-reducing-drug-efflux-in-cancer-cells-and-extending-circulation-in-blood-stream
#20
Jin-Wook Kang, Hyun-Jong Cho, Hyo Jung Lee, Hyo-Eon Jin, Han-Joo Maeng
Polyethylene glycol (PEG)-decorated doxorubicin (Dox)/carboxymethyl chitosan (CMC)/gold nanoparticles (AuNPs) have been developed for cancer therapy. CMC was used as a reducing and stabilizing agent for the fabrication of AuNPs and Dox was loaded onto AuNPs as a chemotherapeutic agent. Dox-loaded CMC-stabilized AuNPs (Dox/CMC-AuNPs) with a mean diameter of 104.0 nm, zeta potential of -48.32 mV, and drug loading efficiency of 60.14% were prepared. PEG was attached to CMC-AuNPs for enhancing systemic drug exposure and prolonging the circulation in blood stream...
December 3, 2018: International Journal of Biological Macromolecules
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