Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Spectroscopic Studies of New Fluorescent Nanomaterial Composed of Silver Atoms and Organic Dye
Kanyuk M.I.,Demchenko A.P.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2013,
Abstract: The novel fluorescent nanostructures are synthesized in a simple one-step process by UV light illumination of silver salt in a mixture with organic dye Thioflavin T. The latter serves both as a sensitizer in photoreaction and as molecular support. The most stable composite structures are obtained in 2-propanol. They are characterized by absorption spectra that are quite different from that of the dye and by strong excitation and emission bands with the maxima at 340 nm and 450 nm correspondingly. We suggest that this photoreaction product consists of two silver atoms and two dye molecules. We believe that this new fluorescent nanoscale material will find many applications in biosensing and bioimaging technologies.
Multi-dye theranostic nanoparticle platform for bioimaging and cancer therapy
Singh AK, Hahn MA, Gutwein LG, Rule MC, Knapik JA, Moudgil BM, Grobmyer SR, Brown SC
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S28357
Abstract: lti-dye theranostic nanoparticle platform for bioimaging and cancer therapy Original Research (8101) Total Article Views Authors: Singh AK, Hahn MA, Gutwein LG, Rule MC, Knapik JA, Moudgil BM, Grobmyer SR, Brown SC Published Date June 2012 Volume 2012:7 Pages 2739 - 2750 DOI: http://dx.doi.org/10.2147/IJN.S28357 Received: 18 November 2011 Accepted: 24 December 2011 Published: 03 June 2012 Amit K Singh,1,2 Megan A Hahn,2 Luke G Gutwein,3 Michael C Rule,4 Jacquelyn A Knapik,5 Brij M Moudgil,1,2 Stephen R Grobmyer,3 Scott C Brown,2,6 1Department of Materials Science and Engineering, College of Engineering, 2Particle Engineering Research Center, College of Engineering, 3Division of Surgical Oncology, Department of Surgery, College of Medicine, 4Cell and Tissue Analysis Core, McKnight Brain Institute, 5Department of Pathology, College of Medicine, University of Florida, Gainesville, FL, USA; 6DuPont Central Research and Development, Corporate Center for Analytical Science, Wilmington, DE, USA Background: Theranostic nanomaterials composed of fluorescent and photothermal agents can both image and provide a method of disease treatment in clinical oncology. For in vivo use, the near-infrared (NIR) window has been the focus of the majority of studies, because of greater light penetration due to lower absorption and scatter of biological components. Therefore, having both fluorescent and photothermal agents with optical properties in the NIR provides the best chance of improved theranostic capabilities utilizing nanotechnology. Methods: We developed nonplasmonic multi-dye theranostic silica nanoparticles (MDT-NPs), combining NIR fluorescence visualization and photothermal therapy within a single nanoconstruct comprised of molecular components. A modified NIR fluorescent heptamethine cyanine dye was covalently incorporated into a mesoporous silica matrix and a hydrophobic metallo-naphthalocyanine dye with large molar absorptivity was loaded into the pores of these fluorescent particles. The imaging and therapeutic capabilities of these nanoparticles were demonstrated in vivo using a direct tumor injection model. Results: The fluorescent nanoparticles are bright probes (300-fold enhancement in quantum yield versus free dye) that have a large Stokes shift (>110 nm). Incorporation of the naphthalocyanine dye and exposure to NIR laser excitation results in a temperature increase of the surrounding environment of the MDT-NPs. Tumors injected with these NPs are easily visible with NIR imaging and produce significantly elevated levels of tumor necrosis (95%) upon photothermal ablation compared with controls, as evaluated by bioluminescence and histological analysis. Conclusion: MDT-NPs are novel, multifunctional nanomaterials that have optical properties dependent upon the unique incorporation of NIR fluorescent and NIR photothermal dyes within a mesoporous silica platform.
The Study of the Interaction of Mesenchymal Stem Cells and the Numor Using the Methods of Fluorescent Bioimaging  [PDF]
А.V. Meleshina,Е.I. Cherkasova,Е.А. Sergeeva,М.S. Kleshnin
Sovremennye Tehnologii v Medicine , 2012,
Abstract: The aim of the investigation is to study the pathogenesis of tumor development when interacting with mesenchymal stem cells transfected by a gene of red fluorescent protein using the method of vital bioimaging. Materials and Methods. There were used adipose-derived adult stem (ADAS) cells taken from human adipose tissue. ADAS were transfected by a gene of red fluorescent protein Turbo FP635 (Close Joint Stock Company “Eurogene”, Russia) by the method of lentiviral transfection. Tumors were implanted to nude mice by subcutaneous injection of Hela Kyoto tumor cells (cervical cancer). ADAS labeled by fluorescent protein were injected to animals at different stages of carcinogenesis (0 and 8 days after tumor culture injection) by various ways: locally — in the tumor node forming region, and systemically — intravenously, in the tail vein. There were formed the following groups of animals: 1st group — an early stage of carcinogenesis (immediately after the injection) and systemic injection of ADAS; 2nd group — an early stage of carcinogenesis and local injection of ADAS; 3rd group — the stage of developed tumor (8 days) and systemic injection of ADAS. The control group consisted of the animals with induced tumor without stem cells injection.Results. ADAS isolated and characterized with the help of immunocytochemical analysis had the phenotype of mesenchymal stem cells (there were expressed CD105, CD49d, STRO-1) and were differentiated in vitro in adipogenic, osteogenic, and chondrogenic approaches in induction media cultivation. The efficiency of transfection of ADAS by red fluorescent protein Turbo FP635 was 75%. The stem cells under study — ADAS labeled by red fluorescent protein Turbo FP635 in systemic injection were shown to be able to migrate in spleen, and in systemic and local injection — in bone marrow, lungs, and recipient’s tumor tissues. The methods of fluorescent bioimaging and laser scanning microscopy can be used to study the interaction between the tumor and mesenchymal stem cells. They effectively complement each other in gaining general knowledge of the distribution of migratory fluorescent cells.
A Fluorescent One-Dimensional Photonic Crystal for Label-Free Biosensing Based on Bloch Surface Waves  [PDF]
Francesca Frascella,Serena Ricciardi,Paola Rivolo,Valeria Moi,Fabrizio Giorgis,Emiliano Descrovi,Francesco Michelotti,Peter Munzert,Norbert Danz,Lucia Napione,Maria Alvaro,Federico Bussolino
Sensors , 2013, DOI: 10.3390/s130202011
Abstract: A one-dimensional photonic crystal (1DPC) based on a planar stack of dielectric layers is used as an optical transducer for biosensing, upon the coupling of TE-polarized Bloch Surface Waves (BSW). The structure is tailored with a polymeric layer providing a chemical functionality facilitating the covalent binding of orienting proteins needed for a subsequent grafting of antibodies in an immunoassay detection scheme. The polymeric layer is impregnated with Cy3 dye, in such a way that the photonic structure can exhibit an emissive behavior. The BSW-coupled fluorescence shift is used as a means for detecting refractive index variations occurring at the 1DPC surface, according to a label-free concept. The proposed working principle is successfully demonstrated in real-time tracking of protein G covalent binding on the 1DPC surface within a fluidic cell.
Antibiotic Conjugated Fluorescent Carbon Dots as a Theranostic Agent for Controlled Drug Release, Bioimaging, and Enhanced Antimicrobial Activity  [PDF]
Mukeshchand Thakur,Sunil Pandey,Ashmi Mewada,Vaibhav Patil,Monika Khade,Ekta Goshi,Madhuri Sharon
Journal of Drug Delivery , 2014, DOI: 10.1155/2014/282193
Abstract: A novel report on microwave assisted synthesis of bright carbon dots (C-dots) using gum arabic (GA) and its use as molecular vehicle to ferry ciprofloxacin hydrochloride, a broad spectrum antibiotic, is reported in the present work. Density gradient centrifugation (DGC) was used to separate different types of C-dots. After careful analysis of the fractions obtained after centrifugation, ciprofloxacin was attached to synthesize ciprofloxacin conjugated with C-dots (Cipro@C-dots conjugate). Release of ciprofloxacin was found to be extremely regulated under physiological conditions. Cipro@C-dots were found to be biocompatible on Vero cells as compared to free ciprofloxacin (1.2?mM) even at very high concentrations. Bare C-dots (~13?mg?mL?1) were used for microbial imaging of the simplest eukaryotic model—Saccharomyces cerevisiae (yeast). Bright green fluorescent was obtained when live imaging was performed to view yeast cells under fluorescent microscope suggesting C-dots incorporation inside the cells. Cipro@C-dots conjugate also showed enhanced antimicrobial activity against both model gram positive and gram negative microorganisms. Thus, the Cipro@C-dots conjugate paves not only a way for bioimaging but also an efficient new nanocarrier for controlled drug release with high antimicrobial activity, thereby serving potential tool for theranostics. 1. Introduction Carbon quantum dots or carbon dots (C-dots) have become a colossal designation in the field of material science, since its serendipitous inception in 2004 during separation of multiwalled carbon nanotubes under electrical influence [1]. In medicine and theranostics, C-dots have emerged as new advancement owing to their exceptional biocompatibility [2], typical optical properties [3], nontoxic precursors as carbon sources, high aqueous solubility, and easy surface functionalization, unlike semiconductor quantum dots such as CdTe and CdSe. [4, 5]. Another catchy attribute of C-dots is their photoluminescence (PL) in near-infrared region (NIR) which can be potentially used for photothermal therapy of tumors [6, 7]. There is significant advancement in synthetic protocols for fabrication of fluorescent C-dots over the past few years. Most celebrated among them is microwave mediated synthesis [1], laser ablation of graphite [8], thermal cracking of organic compounds [9], electrooxidation of graphite [10], and oxidation of candle soot [11]. Moreover, there are very few reports on fabrication of C-dots using natural plant materials as carbon source. Recently, C-dot was synthesized using orange juice
Elution of Labile Fluorescent Dye from Nanoparticles during Biological Use  [PDF]
Tiziana Tenuta, Marco P. Monopoli, JongAh Kim, Anna Salvati, Kenneth A. Dawson, Peter Sandin, Iseult Lynch
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0025556
Abstract: Cells act as extremely efficient filters for elution of unbound fluorescent tags or impurities associated with nanoparticles, including those that cannot be removed by extensive cleaning. This has consequences for quantification of nanoparticle uptake and sub-cellular localization in vitro and in vivo as a result of the presence of significant amount of labile dye even following extensive cleaning by dialysis. Polyacrylamide gel electrophoresis (PAGE) can be used to monitor the elution of unbound fluorescent probes from nanoparticles, either commercially available or synthesized in-house, and to ensure their complete purification for biological studies, including cellular uptake and sub-cellular localisation. Very different fluorescence distribution within cells is observed after short dialysis times versus following extensive dialysis against a solvent in which the free dye is more soluble, due to the contribution from free dye. In the absence of an understanding of the presence of residual free dye in (most) labeled nanoparticle solutions, the total fluorescence intensity in cells following exposure to nanoparticle solutions could be mis-ascribed to the presence of nanoparticles through the cell, rather than correctly assigned to either a combination of free-dye and nanoparticle-bound dye, or even entirely to free dye depending on the exposure conditions (i.e. aggregation of the particles etc). Where all of the dye is nanoparticle-bound, the particles are highly localized in sub-cellular organelles, likely lysosomes, whereas in a system containing significant amounts of free dye, the fluorescence is distributed through the cell due to the free diffusion of the molecule dye across all cellular barriers and into the cytoplasm.
Microencapsulation of self-healing agents containing a fluorescent dye
J. K. Lee,H. H. Noh
eXPRESS Polymer Letters , 2013, DOI: 10.3144/expresspolymlett.2013.8
Abstract: Two different self-healing agent candidates, endo-dicyclopentadiene (endo-DCPD) and 5-ethylidene-2-norbornene (ENB), containing a fluorescent dye surrounded by a melamine–urea–formaldehyde (MUF) shell were microencapsulated by in-situ polymerization and the resulting microcapsules were characterized in this work. The microcapsules showed a narrow size distribution with a spherical shape and rough outer and smooth inner surfaces for both healing agent systems. Shell thicknesses of the microcapsules were ~880±80 nm for endo-DCPD and ~620±60 nm for ENB. The incorporation of a fluorescent dye as tracer into self-healing agents did not disturb the formation of microcapsules. The release of self-healing liquid into the induced crack from ruptured microcapsules in an epoxy coating layer was observed using a fluorescence microscopy. The use of a fluorescent dye is very effective in the observation of a damage site.
Fluorescent Sensing of Chlorophenols in Water Using an Azo Dye Modified β-Cyclodextrin Polymer  [PDF]
Phendukani Ncube,Rui W. Krause,Bhekie B. Mamba
Sensors , 2011, DOI: 10.3390/s110504598
Abstract: A water soluble azo dye modified β-cyclodextrin polymer 4 was synthesized and used as a chemosensor for the detection of chlorinated phenols, model chlorinated by-products (CBPs) of water treatment for drinking purposes. The characterization of the intermediates and the azo dye modified β-CD polymer was done by UV/Vis Spectrophotometry, FT-IR and 1H-NMR spectroscopies. The chlorophenols were capable of quenching the fluorescence of the polymer. The polymer showed greater sensitivity towards 2,4-dichlorophenol, with a sensitivity factor of 0.35 compared to 0.05 and 0.12 for phenol and 4-chlorophenol, respectively. The stability constants (Ks) of the pollutants were also determined by the Benesi-Hildebrand method to be 2.104 × 103 M?1 for 2,4-dichlorophenol and 1.120 × 102 M?1 for 4-chlorophenol.
Evaluation of Economical and Ecological Aspects of Denim Garments Dyeing with Fluorescent Dye  [PDF]
Muhammad Abdur Rashid, Md. Delwar Hossain, Muhammad Mufidul Islam, Md. Nakib-Ul-Hasan
Journal of Materials Science and Chemical Engineering (MSCE) , 2013, DOI: 10.4236/msce.2013.17001

In this study the existing process (3 steps) and proposed process (2 steps) were evaluated during dyeing of denim fabric with fluorescent dye. It compared the effectiveness of these two processes of fluorescent dyeing in the textile industry. Here at first the grey denim fabric was pretreated by scouring and bleaching. Then the fabric was dyed in existing process i.e. through catanizing, dyeing and binding at 10% and 15% shades. Again the pretreated fabric was dyed in proposed process i.e. through catanizing and (dyeing and binding) with same shades. Then the properties of two types of dyed fabric were compared. This study provides a set of experimental results, discussion and comparison between the two processes. The results show that the proposed process has less power and time consumption and more water savings compared to existing process. So the evaluation reflected that the proposed process was much more effective than existing process of denim dyeing with fluorescent dye.

Prospects of Nanobiomaterials for Biosensing  [PDF]
Ravindra P. Singh
International Journal of Electrochemistry , 2011, DOI: 10.4061/2011/125487
Abstract: Progress and development in biosensor development will inevitably focus upon the technology of the nanomaterials that offer promise to solve the biocompatibility and biofouling problems. The biosensors using smart nanomaterials have applications for rapid, specific, sensitive, inexpensive, in-field, on-line and/or real-time detection of pesticides, antibiotics, pathogens, toxins, proteins, microbes, plants, animals, foods, soil, air, and water. Thus, biosensors are excellent analytical tools for pollution monitoring, by which implementation of legislative provisions to safeguard our biosphere could be made effectively plausible. The current trends and challenges with nanomaterials for various applications will have focus biosensor development and miniaturization. All these growing areas will have a remarkable influence on the development of new ultrasensitive biosensing devices to resolve the severe pollution problems in the future that not only challenges the human health but also affects adversely other various comforts to living entities. This review paper summarizes recent progress in the development of biosensors by integrating functional biomolecules with different types of nanomaterials, including metallic nanoparticles, semiconductor nanoparticles, magnetic nanoparticles, inorganic/organic hybrid, dendrimers, and carbon nanotubes/graphene. 1. Introduction Nanomaterial utilizes nanoscale engineering and system integration of existing materials to develop better materials and products. Applications of nanomaterials have made their presence strongly felt in various areas like healthcare, implants, and prostheses; smart textiles, energy generation and conservation with energy generating materials and highly efficient batteries, defence, security, terrorism, and surveillance [1]. Bionanomaterial’s research has emerged as a new exciting field, recognized as a new interdisciplinary frontier in the field of life science and material science. Great advances in nanobiochip materials, nanoscale biomimetic materials, nanomotors, nanocomposite materials, interface biomaterials, nanobiosensors, and nano-drug-delivery systems have the enormous prospect in industrial, defense, and clinical medicine applications. Biomolecules assume the very important role in nanoscience and nanotechnology, for example, peptide nucleic acids (PNAs) replace DNA, act as a biomolecular tool/probe in the molecular genetics, diagnostics, cytogenetics, and have enormous potentials in pharmaceutics for the development of biosensors. Biosensor consists of a biosensing material and a
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.