Search query: Semiconductor nanocrystals as fluorescent biological labels

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abstract: Semiconductor nanocrystals were prepared for use as fluorescent probes in biological staining and diagnostics. Compared with conventional fluorophores, the nanocrystals have a narrow, tunable, symmetric emission spectrum and are photochemically stable. The advantages of the broad, continuous excitation spectrum were demonstrated in a dual emission, single excitation labeling experiment on mouse fibroblasts. These nanocrystal probes are thus complementary and in some cases may be superior to existing fluorophores.
author_names: Marcel P Bruchez

Mario M Moronne

Pi Gin

Shimon Weiss

A Paul Alivisatos
title: Semiconductor nanocrystals as fluorescent biological labels.
venue: Science
year: 1998

abstract: To investing the applying value of the novel fluorescent probe semiconductor quantum dot in immunofluorescence assay.We detected the expression of HSP70 in renal cell carcinoma tissure sections with semiconductor quantum dot(QD605)or conventional organic dye FITC as fluorescent labels,compared image difference and photostability.All labeling signals of quantum dot were found to be more specific and brighter than those of FITC.Moreover,the quantum dot exhibited exceptional photostability during continuous illumination for 1 h by a 488 nm laser.semiconductor quantum dot as fluorescent probe can offer substantial advantages over exsiting fluorophores in IFA for detecting tumor biomarkers.
author_names: Yang Huan
title: Semiconductor nanocrystals as fluorescent biological labels for detecting the expression of HSP70 in renal cell carcinoma tissure
year: 2006

abstract: Quantum dots are superior to dye molecules in many aspects from size tunable fluorescence and resistance to photobleaching and they have thus been widely used in biology as fluorescent probes. However, the cytotoxicity of some quantum dots limits their use in biological systems, and exploiting green nanoparticles with low cytotoxicity has become one major concern in this field. Silicon carbide, one well known power electronic semiconductor material, is considered one of the best biocompatible materials, especially to blood. In addition, it has superior properties such as low density, high hardness, high strength, and chemical inertness. In recent years, much effort has been made to synthesize nanocrystalline SiC and study its photoluminescence (PL) properties. Some synthesized SiC nanostructures showed emission in the blue to UV range with their properties depending sensitively on the fabrication method and even on specific experiments. Although some variations have been reported, in general the observed emissions can be ascribed to some surface or defect states in the SiC nanostructures. However, owing to their relatively large size, low emission intensity, lack of controlled synthesis, and variable optical properties, these interconnected SiC nanostructures can hardly be used as fluorescent biological labels. Kassiba and co workers synthesized SiC nanoparticles with diameters of tens of nanometers
author_names: Jiyang Fan

Hongxia Li

Jingyin Jiang

Leo K -Y So

Yun Wah Lam

Paul K Chu
title: 3C SiC nanocrystals as fluorescent biological labels.
venue: Small
year: 2008

abstract: In this paper, we report the development of rod shaped semiconductor nanocrystals (quantum rods) as fluorescent biological labels. Water soluble biocompatible quantum rods have been prepared by surface silanization and applied for nonspecific cell tracking as well as specific cellular targeting. Quantum rods are brighter single molecule probes as compared to quantum dots. They have many potential applications as biological labels in situations where their properties offer advantages over quantum dots.
author_names: Aihua Fu

Weiwei Gu

Benjamin Boussert

Kristie J Koski

Daniele Gerion

Liberato Manna

Mark A Le Gros

Carolyn A Larabell

A Paul Alivisatos
title: Semiconductor quantum rods as single molecule fluorescent biological labels.
venue: Nano letters
year: 2007

abstract: Detection of single, fluorescently labeled biomolecules is providing a powerful approach to measuring molecular transport, biomolecular interactions, and localization in biological systems. Because the biological molecules of interest rarely exhibit sufficient intrinsic fluorescence to allow observation of individual molecules, they are usually labeled with fluorescent dye molecules, fluorescent proteins, semiconductor nanocrystals or quantum dots, or fluorescently doped silica or polymer nanospheres to allow their detection. Differences in the photophysical and spectral properties of different labels allow one to identify individual molecules by distinguishing their corresponding labels. A simple approach to measuring fluorescence spectra of individual fluorescent labels can be implemented in a standard wide field fluorescence microscope, where a grating or prism is incorporated into the path from the microscope to an imaging detector to disperse the emission spectrum. In this work, principal components and cluster analysis are applied to the identification of fluorescence spectra from single fluorescent labels, with statistical tests of the classification results. Spectra are determined from diffracted images of fluorescent nanospheres labels, where emission maxima are separated by less than 20 nm, and of single dye molecule labels with 30 nm separation. Clusters of points in an eigenvector representation of the spectra correctly classify known labels (both nanospheres and single molecules) and unambiguously identify unknown labels in mixtures.
author_names: Emily C Heider

Moussa Barhoum

Eric M Peterson

Jonathan J Schaefer

Joel M Harris
title: Identification of Single Fluorescent Labels Using Spectroscopic Microscopy
venue: Applied spectroscopy
year: 2010

abstract: In this Article, we study the development of semiconductor nanocrystals (quantum dots of average diameter less than 2 nm) directly conjugated to a transporter protein human serum albumin (HSA) as fluorescent biological labels. Forster resonance energy transfer (FRET) from the amino acid tryptophan (Trp214) to quantum dot in HSA is monitored to follow the local and global changes in the protein structure during thermal unfolding and refolding processes. This study is likely to attract widespread attention as a powerful tool for the study of protein folding.
author_names: Rupa Sarkar

S Shankara Narayanan

Lars-Olof Palsson

Fernando B Dias

Andrew P Monkman

Samir Kumar Pal
title: Direct conjugation of semiconductor nanocrystals to a globular protein to study protein folding intermediates.
venue: The journal of physical chemistry. B
year: 2007

abstract: In recent years, semiconductor nanocrystal quantum dots havegarnered the spotlight as an important new class of biological labelingtool. Withoptical properties superior to conventional organicfluorophores from many aspects, such as high photostability andmultiplexing capability, quantum dots have been applied in a variety ofadvanced imaging applications. This dissertation research goes along withlarge amount of research efforts in this field, while focusing on thedesign and development of new nanoprobes from semiconductor nanocrystalsthat are aimed for useful imaging or sensing applications not possiblewith quantum dots alone. Specifically speaking, two strategies have beenapplied. In one, we have taken advantage of the increasing capability ofmanipulating the shape of semiconductor nanocrystals by developingsemiconductor quantum rods as fluorescent biological labels. In theother, we have assembled quantum dots and gold nanocrystals into discretenanostructures using DNA. The background information and synthesis,surface manipulation, property characterization and applications of thesenew nanoprobes in a few biological experiments are detailed in thedissertation.
author_names: Aihua Fu
title: Developing New Nanoprobes from Semiconductor Nanocrystals
year: 2006

abstract: Recent advances in nanomaterials have produced a new class of fluorescent labels by conjugating semiconductor quantum dots with biorecognition molecules. These nanometer sized conjugates are water soluble and biocompatible, and provide important advantages over organic dyes and lanthanide probes. In particular, the emission wavelength of quantum dot nanocrystals can be continuously tuned by changing the particle size, and a single light source can be used for simultaneous excitation of all different sized dots. High quality dots are also highly stable against photobleaching and have narrow, symmetric emission spectra. These novel optical properties render quantum dots ideal fluorophores for ultrasensitive, multicolor, and multiplexing applications in molecular biotechnology and bioengineering.
author_names: Warren C W Chan

Dustin J Maxwell

Xiaohu Gao

Robert E Bailey

Mingyong Han

Shuming Nie
title: Luminescent quantum dots for multiplexed biological detection and imaging.
venue: Current opinion in biotechnology
year: 2002

abstract: The use of semiconductor nanocrystals (quantum dots) as fluorescent labels for multiphoton microscopy enables multicolor imaging in demanding biological environments such as living tissue. We characterized water soluble cadmium selenide zinc sulfide quantum dots for multiphoton imaging in live animals. These fluorescent probes have two photon action cross sections as high as 47,000 Goeppert Mayer units, by far the largest of any label used in multiphoton microscopy. We visualized quantum dots dynamically through the skin of living mice, in capillaries hundreds of micrometers deep. We found no evidence of blinking (fluorescence intermittency) in solution on nanosecond to millisecond time scales.
author_names: Daniel R Larson

Warren R Zipfel

Rebecca M E Williams

Stephen Clark

Marcel P Bruchez

Frank W Wise

Watt W Webb
title: Water Soluble Quantum Dots for Multiphoton Fluorescence Imaging in Vivo
venue: Science
year: 2003

abstract: Robust and bright light emitters, semiconductor nanocrystals [quantum dots (QDs) have been adopted as a new class of fluorescent labels. Six years after the first experiments of their uses in biological applications, there have been dramatic improvements in understanding surface chemistry, biocompatibility, and targeting specificity. Many studies have shown the great potential of using quantum dots as new probes in vitro and in vivo. This review summarizes the recent advances of quantum dot usage at the cellular level, including immunolabeling, cell tracking, in situ hybridization, FRET, in vivo imaging, and other related technologies. Limitations and potential future uses of quantum dot probes are also discussed.
author_names: A Paul Alivisatos

Weiwei Gu

Carolyn A Larabell
title: Quantum dots as cellular probes.
venue: Annual review of biomedical engineering
year: 2005