Nanobiotechnology: quantum dots in bioimaging (original) (raw)
Related papers
Semiconductor quantum dots for bioimaging and biodiagnostic applications
Annual review of analytical chemistry (Palo Alto, Calif.), 2013
Semiconductor quantum dots (QDs) are light-emitting particles on the nanometer scale that have emerged as a new class of fluorescent labels for chemical analysis, molecular imaging, and biomedical diagnostics. Compared with traditional fluorescent probes, QDs have unique optical and electronic properties such as size-tunable light emission, narrow and symmetric emission spectra, and broad absorption spectra that enable the simultaneous excitation of multiple fluorescence colors. QDs are also considerably brighter and more resistant to photobleaching than are organic dyes and fluorescent proteins. These properties are well suited for dynamic imaging at the single-molecule level and for multiplexed biomedical diagnostics at ultrahigh sensitivity. Here, we discuss the fundamental properties of QDs; the development of next-generation QDs; and their applications in bioanalytical chemistry, dynamic cellular imaging, and medical diagnostics. For in vivo and clinical imaging, the potential ...
Quantum dots for detection, identification and tracking of single biomolecules in tissue and cells
The study of basic cell ultrastructure and intracellular physiological functions has been greatly aided by detection and identifi cation of single macromolecules. Since the current in situ labeling methods for directly correlative (light and electron) microscopy observations have a number of substantial limitations, the semiconductor nanocrystals quantum dots gain distinguished with long-term imaging and high photostability. The quantum dots (Qdots) have quickly fi lled in the role, being found to be superior to traditional organic dyes on several counts. It has been estimated that Qdots are 20 times brighter and 100 times more stable than traditional fl uorescent reporters. Nowadays, a wide variety of quantum dots conjugated to secondary antibodies suitable for multiple labeling have become commercially available. They make possible the study of biological processes, both in the membrane or in the cytoplasm, at a truly molecular scale and with high spatial and temporal resolutions. By applying Qdots with different size and color light we might achieve multiple labeling of proteins. However, the use of particles with different size is problematic for high-resolution imaging, semi-quantitative measurement of epitope numbers, or when epitope density is high. Recently we report new electron microscopy method for immunolabeling, where two approaches are performed to distinguish yet unattainable spatial resolution: i) for fi rst time as small as 1 nm nanoparticles were applied and observed and ii) the scanning transmission electron microscope (STEM) equipped with an energy dispersive X-ray (EDX) detector were used to distinguish equal in size small labels. We prove that various quantum dots in the range between 1–5 nm can be observed and identified at these conditions. Our method is not limited by the necessity of using labels of different sizes and, therefore could open a number of new biological applications requiring small labels. Because the only requirement is that labels have different chemical compositions that can be differentiated by an EDX spectrometer, this method is not restricted to only two labels. The number of different labels depends on the number of species with sufficiently different X-ray spectra that can be produced.
Chemical analysis and cellular imaging with quantum dots
The Analyst, 2004
Quantum dots are tiny light-emitting particles on the nanometer scale. They are emerging as a new class of biological labels with properties and applications that are not available with traditional organic dyes and fluorescent proteins. Their novel properties such as improved brightness, resistance against photobleaching, and multicolor light emission, have opened new possibilities for ultrasensitive chemical analysis and cellular imaging. In this Research Highlight article, we discuss the unique optical properties of semiconductor quantum dots, surface chemistry and bioconjugation, current applications in bioanalytical chemistry and cell biology, and future research directions.
Luminescent quantum dots for multiplexed biological detection and imaging
Current Opinion in Biotechnology, 2002
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.
Advances in fluorescence imaging with quantum dot bio-probes
Biomaterials, 2006
After much effort in surface chemistry development and optimization by several groups, fluorescent semiconductor nanocrystals probes, also known as quantum dots or qdots, are now entering the realm of biological applications with much to offer to biologists. The road to success has been paved with hurdles but from these efforts has stemmed a multitude of original surface chemistries that scientists in the biological fields can draw from for their specific biological applications. The ability to easily modulate the chemical nature of qdot surfaces by employing one or more of the recently developed qdot coatings, together with their exceptional photophysics have been key elements for qdots to acquire a status of revolutionary fluorescent bio-probes. Indeed, the unique properties of qdots not only give biologists the opportunity to explore advanced imaging techniques such as single molecule or lifetime imaging but also to revisit traditional fluorescence imaging methodologies and extract yet unobserved or inaccessible information in vitro or in vivo.
2010
Quantum dots (QDs) are extremely bright fluorescent imaging probes that are particularly useful for tracking individual molecules in living cells. Here, we show how a two-component system composed of a high-affinity single-chain fragment antibody and its cognate hapten (fluorescein) can be utilized for tracking individual proteins in various cell types. The single-chain fragment antibody against fluorescein is genetically appended to the protein of interest, while the hapten fluorescein is attached to the end of the peptide that is used to coat the QDs. We describe (i) the method used to functionalize QDs with fluorescein peptides; (ii) the method used to control the stoichiometry of the hapten on the surface of the QD; and (iii) the technical details necessary to observe single molecules in living cells. 2005), the bis-arsenical/SplAsH (spirolactam Arsenical Hairpin binder) system (Bhunia and Miller, 2007), biotin/streptavidin (Weber et al., 1989), and barnase/barstar (Wang et al., 2004). QDs have emerged as a very promising class of fluorophores for multiple biological applications (Michalet et al., 2005), including live cell imaging. Labeling cellular proteins
Pushing the limits of detection for proteins secreted from single cells using quantum dots
The Analyst, 2018
Single cell analysis methods are increasingly being utilized to investigate how individual cells process information and respond to diverse stimuli. Soluble proteins play a critical role in controlling cell populations and tissues, but directly monitoring secretion is technically challenging. Microfabricated well arrays have been developed to assess secretion at the single cell level, but these systems are limited by low detection sensitivity. Semiconductor quantum dots (QD) exhibit remarkably bright and photostable luminescence signal, but to date they have not been evaluated in single cell secretion studies using microfabricated well arrays. Here, we used QDs in a sandwich immunoassay to detect secretion of the soluble cytokine tumor necrosis factor-α (TNF-α) from single cells. To enhance detection sensitivity, we employed two different strategies. First, we used a unique single QD imaging approach, which provided a detection threshold (180 attomolar) that was >100-fold lower t...