http://www.mdpi.com/journal/ijms/special_issues/quantum_dots/ Dear Colleagues, The introduction of Quantum Dots for research purposes has significantly contributed to our understanding of various fundamental questions and phenomena in Biomedicine and Life Sciences and comprises a rapidly developing field of science. Novel synthesis methods have provided a wide spectrum of Quantum Dots and related Nano-crystals and are now utilized in various biomedical applications, such as fluorescence microscopy, correlation spectroscopy, single-cell biochemistry, flow cytometry, DNA and protein arrays, immunoassays, cyto-and histochemistry, in situ hybridization, PCR, and Drug screening in a high throughput setting. In order to bring recent developments and advancements in Nano-Crystal technology closer to Life Scientists and Students alike, thus both, educate as well as stimulate the integration of these novel thechnologies into Life Science research efforts, this special issue aims to actively recruit leading scientists in the field to share their knowledge. High quality research papers, methodological papers, reviews or mini-reviews with regard to Synthesis, Biomedical-, and Life Science applications of Quantum Dots are considered for publication. In addition, purely educational papers from which students and researchers may benefit are very welcome. Previously unpublished original experimental and review papers are petitioned for regarding the following and related topics listed under keywords. Dr. Gregor Drummen Guest Editor Leading Papers and Reviews Caruthers, S.D.; Wickline, S.A.; Lanza, G.M. Nanotechnological applications in medicine. Curr. Opin. Biotechnol. 2007, 18, 26-30. Rao, J.; Dragulescu-Andrasi, A.; Yao, H. Fluorescence imaging in vivo: recent advances. Curr. Opin. Biotechnol. 2007, 18, 17-25. Jaiswal, J.K.; Simon, S.M. Imaging single events at the cell membrane. Nat. Chem. Biol. 2007, 3, 92-8. Kaji, N.; Tokeshi, M.; Baba, Y. Quantum dots for single bio-molecule imaging. Anal. Sci. 2007, 23, 21-4. Willner, I.; Basnar, B.; Willner, B. Nanoparticle-enzyme hybrid systems for nanobiotechnology. FEBS J. 2007, 274, 302-9. Review. Hernandez-Sanchez, B.A.; Boyle, T.J.; Lambert, T.N.; Daniel-Taylor, S.D.; Oliver, J.M.; Wilson, B.S.; Lidke, D.S.; Andrews, N.L. Synthesizing biofunctionalized nanoparticles to image cell signaling pathways. IEEE Trans Nanobioscience 2006, 5, 222-30. Gallego, O.; Puntes, V. What can nanotechnology do to fight cancer? Clin. Transl. Oncol. 2006, 8, 788-95. Du, W.; Wang, Y.; Luo, Q.; Liu, B.F. Optical molecular imaging for systems biology: from molecule to organism. Anal. Bioanal. Chem. 2006, 386, 444-57. Jares-Erijman, E.A.; Jovin, T.M. Imaging molecular interactions in living cells by FRET microscopy. Curr. Opin. Chem. Biol. 2006, 10, 409-16. Scholes, G.D.; Rumbles, G. Excitons in nanoscale systems. Nat. Mater. 2006, 5, 683-96. Erratum in: Nat. Mater. 2006, 5, 920. Wang, M.D.; Shin, D.M.; Simons, J.W.; Nie, S. Nanotechnology for targeted cancer therapy. Expert Rev. Anticancer Ther. 2007, 7, 833-7. Submission All papers should be submitted to ijms@mdpi.org. To be published continuously until the deadline and papers will be listed together at the special issue website. Submitted papers should not have been published previously, nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors is available on the Instructions for Authors page. The International Journal of Molecular Sciences is an international peer-reviewed monthly journal published by Molecular Diversity Preservation International. Open Access publication fees are 800 CHF per paper. English correction fees and/or formatting fees (250 CHF) will be added in certain cases (1050 CHF per paper for those papers that require extensive additional formatting and/or English corrections). http://www.mdpi.com/1422-0067/11/1/154/ Imagine devices or particles so small that they are invisible to the naked eye. Imagine that such entities could be used to patrol our bodies and autonomously augment endogenous defense and repair mechanisms. Imagine the defeat of illness at a fraction of the current costs. Bionanotechnology is the field of science that deals with just that: the development of imaging, tracking, targeting, sensing, diagnostic, and eventually therapeutic capabilities based on particles in the nanometer range, i.e., “nanoparticles”. Within the extensive group of nanoparticles, semiconducting quantum dots play a central and prominent role. Quantum dots excel at a myriad of physical properties, most notably their fluorescent properties, such as high quantum yield, photo-stability, broad absorption spectra, and their remarkable size-dependent emission-tunability. http://www.mdpi.com/1422-0067/11/1/154/ Tue, 12 Jan 2010 00:00:00 CET International Journal of Molecular Sciences 2010-01-12 11 1 Editorial 154 163 1422-0067 Quantum Dots—From Synthesis to Applications in Biomedicine and Life Sciences 2010-01-12 doi: 10.3390/ijms11010154 Gregor P.C. Drummen http://www.mdpi.com/1422-0067/10/5/2122/ Quantum dots (QDs) are useful novel luminescent markers, but their embryonic toxicity is yet to be fully established, particularly in oocyte maturation and sperm fertilization. Earlier experiments by our group show that CdSe-core QDs have cytotoxic effects on mouse blastocysts and are associated with defects in subsequent development. Here, we further investigate the influence of CdSe-core QDs on oocyte maturation, fertilization, and subsequent pre- and postimplantation development. CdSe-core QDs induced a significant reduction in the rates of oocyte maturation, fertilization, and in vitro embryo development, but not ZnS-coated CdSe QDs. Treatment of oocytes with 500 nM CdSe-core QDs during in vitro maturation (IVM) led to increased resorption of postimplantation embryos and decreased placental and fetal weights. To our knowledge, this is the first study to report the negative impact of CdSe-core QDs on mouse oocyte development. Moreover, surface modification of CdSe-core QDs with ZnS effectively prevented this cytotoxicity. http://www.mdpi.com/1422-0067/10/5/2122/ Thu, 14 May 2009 00:00:00 CEST International Journal of Molecular Sciences 2009-05-14 10 5 Article 2122 2135 1422-0067 Cytotoxic Effects of CdSe Quantum Dots on Maturation of Mouse Oocytes, Fertilization, and Fetal Development 2009-05-14 doi: 10.3390/ijms10052122 Ming-Shu Hsieh Nion-Heng Shiao Wen-Hsiung Chan http://www.mdpi.com/1422-0067/10/4/1930/ Quantum dot (QD) labeling combined with fluorescence lifetime imaging microscopy is proposed as a powerful transduction technique for the detection of DNA hybridization events. Fluorescence lifetime analysis of DNA microarray spots of hybridized QD labeled target indicated a characteristic lifetime value of 18.8 ns, compared to 13.3 ns obtained for spots of free QD solution, revealing that QD labels are sensitive to the spot microenvironment. Additionally, time gated detection was shown to improve the microarray image contrast ratio by 1.8, achieving femtomolar target sensitivity. Finally, lifetime multiplexing based on Qdot525 and Alexa430 was demonstrated using a single excitation-detection readout channel. http://www.mdpi.com/1422-0067/10/4/1930/ Fri, 24 Apr 2009 00:00:00 CEST International Journal of Molecular Sciences 2009-04-24 10 4 Article 1930 1941 1422-0067 Fluorescence Lifetime Imaging of Quantum Dot Labeled DNA Microarrays 2009-04-24 doi: 10.3390/ijms10041930 Gerard Giraud Holger Schulze Till T. Bachmann Colin J. Campbell Andrew R. Mount Peter Ghazal Mizanur R. Khondoker Alan J. Ross Stuart W. J. Ember Ilenia Ciani Chaker Tlili Anthony J. Walton Jonathan G. Terry Jason Crain http://www.mdpi.com/1422-0067/10/2/656/ The use of fluorescent nanoparticles as probes for bioanalytical applications is a highly promising technique because fluorescence-based techniques are very sensitive. Quantum dots (QDs) seem to show the greatest promise as labels for tagging and imaging in biological systems owing to their impressive photostability, which allow long-term observations of biomolecules. The usage of QDs in practical applications has started only recently, therefore, the research on QDs is extremely important in order to provide safe and effective biosensing materials for medicine. This review reports on the recent methods for the preparation of quantum dots, their physical and chemical properties, surface modification as well as on some interesting examples of their experimental use. http://www.mdpi.com/1422-0067/10/2/656/ Fri, 20 Feb 2009 00:00:00 CET International Journal of Molecular Sciences 2009-02-20 10 2 Review 656 673 1422-0067 Quantum Dots — Characterization, Preparation and Usage in Biological Systems 2009-02-20 doi: 10.3390/ijms10020656 Jana Drbohlavova Vojtech Adam Rene Kizek Jaromir Hubalek http://www.mdpi.com/1422-0067/10/2/441/ In the past few decades, technology has made immeasurable strides to enable visualization, identification, and quantitation in biological systems. Many of these technological advancements are occurring on the nanometer scale, where multiple scientific disciplines are combining to create new materials with enhanced properties. The integration of inorganic synthetic methods with a size reduction to the nano-scale has lead to the creation of a new class of optical reporters, called quantum dots. These semiconductor quantum dot nanocrystals have emerged as an alternative to organic dyes and fluorescent proteins, and are brighter and more stable against photobleaching than standard fluorescent indicators. Quantum dots have tunable optical properties that have proved useful in a wide range of applications from multiplexed analysis such as DNA detection and cell sorting and tracking, to most recently demonstrating promise for in vivo imaging and diagnostics. This review provides an in-depth discussion of past, present, and future trends in quantum dot use with an emphasis on in vivo imaging and its related applications. http://www.mdpi.com/1422-0067/10/2/441/ Tue, 03 Feb 2009 00:00:00 CET International Journal of Molecular Sciences 2009-02-03 10 2 Review 441 491 1422-0067 Quantum Dots for Live Cell and In Vivo Imaging 2009-02-03 doi: 10.3390/ijms10020441 Maureen A. Walling Jennifer A. Novak Jason R. E. Shepard http://www.mdpi.com/1422-0067/9/12/2622/ QDs may offer significant advantages in environmental and bead-based applications where the target cells need to be discriminated above background fluorescence. We have examined the possible applications of QDs for flow cytometric measurements (FCM) by studying their excitation - emission spectra and their binding to paramagnetic beads. We labelled beads with either QDs or a commonly-used fluorochrome (FITC) and studied their fluorescence intensity by FCM. Flow cytometric comparisons indicated that the minimum fluorophore concentration required for detection of QDs above autofluorescent background was 100-fold less than for FITC. http://www.mdpi.com/1422-0067/9/12/2622/ Wed, 17 Dec 2008 00:00:00 CET International Journal of Molecular Sciences 2008-12-17 9 12 Article 2622 2638 1422-0067 Potential Use of Quantum Dots in Flow Cytometry 2008-12-17 doi: 10.3390/ijms9122622 Raquel Ibáñez-Peral Peter L. Bergquist Malcolm R. Walter Moreland Gibbs Ewa M. Goldys Belinda Ferrari http://www.mdpi.com/1422-0067/9/10/2044/ Fluorescent probes that emit in the near-infrared (NIR, 700-1,300 nm) region are suitable as optical contrast agents for in vivo fluorescence imaging because of low scattering and absorption of the NIR light in tissues. Recently, NIR quantum dots (QDs) have become a new class of fluorescent materials that can be used for in vivo imaging. Compared with traditional organic fluorescent dyes, QDs have several unique advantages such as size- and composition-tunable emission, high brightness, narrow emission bands, large Stokes shifts, and high resistance to photobleaching. In this paper, we report a facile method for the preparation of highly fluorescent, water-soluble glutathione (GSH)-coated NIR QDs for in vivo imaging. GSH-coated NIR QDs (GSH-QDs) were prepared by surface modification of hydrophobic CdSeTe/CdS (core/shell) QDs. The hydrophobic surface of the CdSeTe/CdS QDs was exchanged with GSH in tetrahydrofuran-water. The resulting GSH-QDs were monodisperse particles and stable in PBS (phosphate buffered saline, pH = 7.4). The GSH-QDs (800 nm emission) were highly fluorescent in aqueous solutions (quantum yield = 22% in PBS buffer), and their hydrodynamic diameter was less than 10 nm, which is comparable to the size of proteins. The cellular uptake and viability for the GSH-QDs were examined using HeLa and HEK 293 cells. When the cells were incubated with aqueous solutions of the GSH-QDs (10 nM), the QDs were taken into the cells and distributed in the perinuclear region of both cells. After 12 hrs incubation of 4 nM of GSH-QDs, the viabilities of HeLa and HEK 293 cells were ca. 80 and 50%, respectively. As a biomedical utility of the GSH-QDs, in vivo NIRfluorescence imaging of a lymph node in a mouse is presented. http://www.mdpi.com/1422-0067/9/10/2044/ Wed, 29 Oct 2008 00:00:00 CET International Journal of Molecular Sciences 2008-10-29 9 10 Article 2044 2061 1422-0067 Preparation and Characterization of Highly Fluorescent, Glutathione-coated Near Infrared Quantum Dots for in Vivo Fluorescence Imaging 2008-10-29 doi: 10.3390/ijms9102044 Takashi Jin Fumihiko Fujii Yutaka Komai Junji Seki Akitoshi Seiyama Yoshichika Yoshioka