Small Is Now Big: Nano Technology for Electronics (original) (raw)
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International journal of nanomedicine, 2006
Semiconductor quantum dots (QDs) are a new class of fluorescent labels with broad applications in biomedical imaging, disease diagnostics, and molecular and cell biology. In comparison with organic dyes and fluorescent proteins, quantum dots have unique optical and electronic properties such as size-tunable light emission, improved signal brightness, resistance against photobleaching, and simultaneous excitation of multiple fluorescence colors. Recent advances have led to multifunctional nanoparticle probes that are highly bright and stable under complex in vitro and in vivo conditions. New designs involve encapsulating luminescent QDs with amphiphilic block copolymers, and linking the polymer coating to tumor-targeting ligands and drug-delivery functionalities. These improved QDs have opened new possibilities for real-time imaging and tracking of molecular targets in living cells, for multiplexed analysis of biomolecular markers in clinical tissue specimens, and for ultrasensitive ...
Impacts of quantum dots in molecular detection and bioimaging of cancer
Bioimpacts, 2014
Introduction: A number of assays have so far been exploited for detection of cancer biomarkers in various malignancies. However, the expression of cancer biomarker(s) appears to be extremely low, therefore accurate detection demands sensitive optical imaging probes. While optical detection using conventional fluorophores often fail due to photobleaching problems, quantum dots (QDs) offer stable optical imaging in vitro and in vivo. Methods: In this review, we briefly overview the impacts of QDs in biology and its applications in bioimaging of malignancies. We will also delineate the existing obstacles for early detection of cancer and the intensifying use of QDs in advancement of diagnostic devices. Results: Of the QDs, unlike the II-VI type QDs (e.g., cadmium (Cd), selenium (Se) or tellurium (Te)) that possess inherent cytotoxicity, the I-III-VI 2 type QDs (e.g., AgInS 2 , CuInS 2 , ZnS-AgInS 2 ) appear to be less toxic bioimaging agents with better control of band-gap energies. As highly-sensitive bioimaging probes, advanced hybrid QDs (e.g., QD-QD, fluorochrome-QD conjugates used for sensing through fluorescence resonance energy transfer (FRET), quenching, and barcoding techniques) have also been harnessed for the detection of biomarkers and the monitoring of delivery of drugs/genes to the target sites. Antibody-QD (Ab-QD) and aptamer-QD (Ap-QD) bioconjugates, once target the relevant biomarker, can provide highly stable photoluminescence (PL) at the target sites. In addition to their potential as nanobiosensors, the bioconjugates of QDs with homing devices have successfully been used for the development of smart nanosystems (NSs) providing targeted bioimaging and photodynamic therapy (PDT). Conclusion: Having possessed great deal of photonic characteristics, QDs can be used for development of seamless multifunctional nanomedicines, theranostics and nanobiosensors.
In vivo cancer targeting and imaging with semiconductor quantum dots
Nature Biotechnology, 2004
We describe the development of multifunctional nanoparticle probes based on semiconductor quantum dots (QDs) for cancer targeting and imaging in living animals. The structural design involves encapsulating luminescent QDs with an ABC triblock copolymer and linking this amphiphilic polymer to tumor-targeting ligands and drug-delivery functionalities. In vivo targeting studies of human prostate cancer growing in nude mice indicate that the QD probes accumulate at tumors both by the enhanced permeability and retention of tumor sites and by antibody binding to cancer-specific cell surface biomarkers. Using both subcutaneous injection of QD-tagged cancer cells and systemic injection of multifunctional QD probes, we have achieved sensitive and multicolor fluorescence imaging of cancer cells under in vivo conditions. We have also integrated a whole-body macro-illumination system with wavelengthresolved spectral imaging for efficient background removal and precise delineation of weak spectral signatures. These results raise new possibilities for ultrasensitive and multiplexed imaging of molecular targets in vivo. NATURE BIOTECHNOLOGY VOLUME 22 NUMBER 8 AUGUST 2004 969 © 2004 Nature Publishing Group http://www.nature.com/naturebiotechnology
Multicolor quantum dots for molecular diagnostics of cancer
Expert Review of Molecular Diagnostics, 2006
In the pursuit of sensitive and quantitative methods to detect and diagnose cancer, nanotechnology has been identified as a field of great promise. Semiconductor quantum dots are nanoparticles with intense, stable fluorescence, and could enable the detection of tens to hundreds of cancer biomarkers in blood assays, on cancer tissue biopsies, or as contrast agents for medical imaging. With the emergence of gene and protein profiling and microarray technology, high-throughput screening of biomarkers has generated databases of genomic and expression data for certain cancer types, and has identified new cancer-specific markers. Quantum dots have the potential to expand this in vitro analysis, and extend it to cellular, tissue and whole-body multiplexed cancer biomarker imaging.
In vivo Cancer Imaging with Semiconductor Quantum Dots
Current Pharmaceutical Analysis, 2008
Multifunctional nanoparticle probes based on semiconductor quantum dots (QDs) have been developed for cancer targeting and imaging in living animals. Compared with small molecule dyes, the intense fluorescence emission of QDs makes it easier to track single protein molecules, they are remarkably resistant to photobleaching, their narrow emission spectrum facilitates imaging of many proteins simultaneously, and their large two-photon cross sections allow in vivo imaging at greater depths. Since QDs have become commercially available, their use to study protein trafficking has grown rapidly. As an example, in vivo targeting studies of human prostate cancer growing in nude mouse show that the QD probes can be delivered to tumor sites by both enhanced permeation and retention (passive targeting) and by antibody binding to cancer-specific cell surface biomarkers such as prostate-specific membrane antigen (active targeting). Using both subcutaneous injection of QD-tagged cancer cells and the systemic injection of multifunctional QD probes, multicolor fluorescence imaging of as few as 100-1000 cancer cells can be achieved under in vivo conditions. These results suggest that QD probes and spectral imaging can be combined for multiplexed imaging and detection of genes, proteins, and small-molecule drugs in single living cells, and that this imaging modality can be adopted for real-time visualization of cancer cell metastasis in live animals.
Quantum Dots For Diagnosis Of Cancers
Advanced Materials Letters, 2013
The most widely researched and investigated disease, both medically and scientifically, in the current era is the formidable disease cancer. The chances of successful treatment and hence the curability increases if it is diagnosed at an early stage. This can be done only by increasing awareness amongst people about its early diagnosis and screening tests. Cancer screening exams refers to the medical tests to identify people who have disease, often before symptoms of the illness occur. These tests help detecting cancer at its earliest stage when the chances for curing the disease are greatest. Advancements in nanotechnology have made the early screening of cancer possible. In this review, we have discussed the developments in nanotechnology that have encouraged the more recent innovative solutions for early diagnosis and treatment of cancer. Quantum dots, nanometer-sized semiconductors, are the new class of novel biosensors, now being exclusively employed as alternative fluorescent probes due to their unique properties, such as intense and stable fluorescence for a longer time, resistance to photobleaching, large molar extinction coefficients, and highly sensitive detection, due to their ability to absorb and emit light very efficiently. Their size approximates that of individual biomolecules, which offers unique possibilities for the ultrasensitive detection of cancer in persons' serum, tissues, and other body fluids, when tagged with specific antibodies against specific tumor markers. In this review, we have account briefly the applications of semiconductor QDs employed for the early screening and diagnosis of cancer biomarkers between the years 2009-2012. We believe that this review will enable workers in the field to devise new applications of these materials for the early detection of cancer, and ultimate reduction in incidence of the disease.
Quantum dots for molecular diagnostics of tumors
Acta naturae, 2011
Semiconductor quantum dots (QDs) are a new class of fluorophores with unique physical and chemical properties, which allow to appreciably expand the possibilities for the current methods of fluorescent imaging and optical diagnostics. Here we discuss the prospects of QD application for molecular diagnostics of tumors ranging from cancer-specific marker detection on microplates to non-invasive tumor imagingin vivo. We also point out the essential problems that require resolution in order to clinically promote QD, and we indicate innovative approaches to oncology which are implementable using QD.
Nanobio applications of quantum dots in cancer: imaging, sensing, and targeting
Cancer Nanotechnology, 2011
In this article, the syntheses and optical properties of core/shell quantum dot (CdSe/ZnS) and their applications are reviewed. Nevertheless, the main focus is to provide an overview on biological applications of quantum dots that contain imaging, targeting, and sensing. We discuss the different synthetic methods, optical properties (photoluminescence intensity, absorption, and fluorescence spectra), and their dependence on shape, size, and inner structure of quantum dots. Also, the different mechanisms of quantum dots bio-targeting (passive and active mechanisms) are discussed. The impact of quantum dots in bioimaging is reviewed regarding its photoluminescence intensity, absorption and emission spectrum, and photo-stability on high-quality and sensitivity imaging. Further, the difference between near infrared and visible emission quantum dots in deep tissue imaging will be reviewed and some of done works are considered and compared with each other. And finally, the biosensing potential/application of quantum dots in medical diagnosis is going to be highlighted.
Bioconjugated Quantum Dots: A Multifunctional Nanomaterial for the Early Detection of Cancer
Cancer is the leading cause of the death worldwide. About 30% of cancer death is preventable. The early detection and quantification is essential for diagnosis and prevention in the case of cancer. In the past few years cancer nanotechnology has made immeasurable strides to enable visualization, identification and quantization in biological systems, which covers a vast and diverse array of nanomaterials. One such material is Quantum Dots (QDs). It has tunable optical properties that have proved useful in multiplexed analysis such as Biomarker detection, cell sorting and tracking, multimodality targeting and imaging of tumor. These nanocentric agents can provide essential breakthroughs in the fight against cancer. When linked with targeting ligands such as antibodies, peptides or small molecules, QDs can be used to target tumor biomarkers as well as tumor vasculatures with high affinity and specificity. In particular, we focus upon CdSe quantum dots (TOPO coated) which is proved to be a critical nutrient necessary for rapid growth and cell division when conjugated with Folate receptor α (FR α) enhances the differential specificity by targeting folate receptor (FR)-positive cancer cells. This is over expressed in epithelial malignancies and facilitates improved specificity and decrease negative side effects. The synthesis and development of state-of-the-art this Bioconjuagated QDs are examined in this issue to provide more possibilities to detect the early-stage formation of a disease or early molecular changes during diagnosis or treatment of cancer.
Quantum dots for in vivo molecular and cellular imaging
Methods in molecular biology (Clifton, N.J.), 2007
Multifunctional nanoparticle probes based on semiconductor quantum dots (QDs) are developed for simultaneous targeting and imaging of cancer cells in living animals. The structural design involves encapsulating luminescent QDs with an ABC triblock copolymer, and linking this polymer to tumor-targeting ligands, such as antibodies and drug-delivery functionalities. In vivo targeting studies of human prostate cancer growing in nude mouse show that the QD probes can be delivered to tumor sites by both enhanced permeation and retention (passive targeting) and by antibody binding to cancer-specific cell surface biomarkers such as prostate-specific membrane antigen (active targeting). Using both subcutaneous injection of QD-tagged cancer cells and the systemic injection of multifunctional QD probes, multicolor fluorescence imaging of as few as 10-100 cancer cells can be achieved under in vivo conditions. The use of spectrally resolved imaging can efficiently remove autofluorescence backgro...