Bio Imaging with Quantum Dots

Differently luminescent nanocrystals for in vitro cell imaging

Semiconductor quantum dots (QDs) are among the most promising emerging fluorescent labels for cellular imaging. The stunning colors emitted by semiconductor QDs have attracted researchers to unconventional bioimaging over the conventional organic dyes. Quantum dots are interesting fluorescence probes for all types of labeling studies owing to their reduced tendency to photobleach. The optical properties of semiconductor quantum dots, particularly the wavelength of their fluorescence, depend strongly on their size. In short one can say a spectrum of colors can be emitted from a single material simply by changing the dot size. Fluorescent quantum dots (QDs) can be used for long-term and multicolor imaging of cellular and molecular interactions. For labeling specific cellular proteins, QDs must be conjugated to biomolecules that provide binding specificity without any damage to the properties of the molecules. Bioconjugation approaches vary with the surface properties of the hydrophilic QD used. In addition, NIR-emitting QDs can be used to avoid interference from the autofluorescence, since cell, hemoglobin and water have lower absorption coefficient and scattering effects in the NIR region (650 – 900 nm).

Our research team focuses on synthesis of diverse quantum dots of toxic free origin for deep tissue imaging applications. We have synthesized visible and NIR luminescent probes for application as in vivo diagnostic probes. In addition, multifunctional properties of such materials as drug delivery vehicle or/and as photothermal ablators are elaborately studied. We are also equally interested in bioconjugation/surface functionalization approaches for utilizing these probes for high selective and specific diagnostic behavior. In addition, we are also into synthesizing second NIR-window luminescent QD probes for imaging applications.

Selected publications

1. Synthesis of CuAlS2 nanocrystals and its application in bio imaging. Aby Cheruvathoor Poulose, S. Veeranarayanan, Y. Nagaoka, Y. Yoshida, T. Maekawa, D. S. Kumar. Materials Express, 2012, 2:94-104.
   
   
2. PEG Coated Biocompatible Cadmium Chalcogenide Quantum Dots for Targeted Imaging of Cancer Cells. Aby Cheruvathoor Poulose, S. Veeranarayanan, Y. Yoshida, T. Maekawa, D. S. Kumar. Journal of Fluorescence, 2012, 22:931-944.
   
   
3. Uptake of FITC labeled silica nanoparticles and quantum dots by rice seedlings: Effects on seed germination and their potential as bio labels for plants. R. Nair, Aby Cheruvathoor Poulose, Y. Nagaoka, Y. Yoshida, T. Maekawa, D. S. Kumar. Journal of Fluorescence, 2011, 22:537.
   
   
4. Synthesis and application of luminescent single CdS quantum dot encapsulated silica nanoparticles directed for precision optical bioimaging. S. Veeranarayanan, Aby Cheruvathoor Poulose, M. S. Mohamed, Y. Nagaoka, S. Iwai, Y. Nakagame, S. Kashiwada, Y. Yoshida, T. Maekawa, D. S. Kumar. International Journal of Nanomedicine. 2012, 7:3769
   
   
5. . Biocompatible fluorescent jelly quantum dots for bioimaging, Aswathy R. G., B. Sivakumar, D. Brahatheeswaran, R. Ukai, Y. Yoshida, T. Maekawa, D.Sakthi Kumar, Materials Express 2011, 1: 291-298
   
   
6. Near-infrared quantum dots for deep tissue imaging, R. G. Aswathy, Y. Yoshida, T. Maekawa, D. Sakthi Kumar, Analytical and Bioanalytical Chemistry, 397,(4) (2010) 1417-1435