TIFR
Department of Chemical Sciences
School of Natural Sciences

February 12, 2015 at 4.00 pm in AG-80

Title :

Single Molecular Spectroscopy of Single Live Cell

Abstract :

The 2014 Nobel Prize in Chemistry has been awarded for the development of Single Molecule Spectroscopy. We will discuss some recent application of this technique to the study of a single live cell. In a confocal microscope, the size of the focused spot (~200 nm = 0.2 m) is one-hundredth of the dimension of a cell. Thus one can probe different regions/organelles in a cell. Utilizing this, we will describe several new phenomena inside a live cell [1-5]. Specifically, we have discovered found substantial differences between a cancer cell and a normal cell [1-4]. The gold nano-clusters preferentially enter or stain a cancer cell compared to a non-malignant cell [1]. The red-ox processes (thiol-disulfide interconversion) lead to intermittent structural oscillations leading to fluctuations in fluorescence intensity in a single live cell [2-3]. Such oscillations are absent for a cancer cell [2]. The number of lipid droplets are much higher in a cancer cell. We detected stochastic resonance during gene silencing in a cancer cell [5].

References
1.  S. Chattoraj, et al.  "Fluorescent Gold Nano-Cluster inside a Live [UTF-8?]Cell,” J. Phys. Chem. C 118

     (2014, in press).
2.  S. Chattoraj, et al.  "Role of Red-Ox Cycle in Structural Oscillations and Solvation Dynamics in Mitochondria,"

     J. Phys. Chem. B 118 (2014, in press).
3.  S. Ghosh, et al. "Solvation Dynamics and Intermittent Oscillation of a Cell Membrane: " J. Phys. Chem. B 118

     (2014) 2949-2956.  
4.  R. Chowdhury, et al. "Confocal Microscopy of Cytoplasmic Lipid Droplets in a Live Cancer  Cell”

     Med. Chem. Comm. 5 (2014) 536-539.
5.  S. Chattoraj, et al. "Dynamics of Gene Silencing in a Live Cell," J. Phys. Chem. Lett. 5 (2014) 1012-16.