Interactions between semiconductor nanoparticles and biomembranes and DNA

Project Information

Principal Investigator	Jay Nadeau
Institution	McGill University
Project URL	View
Relevance to Implications	High
Class of Nanomaterial	Engineered Nanomaterials
Impact Sector	Human Health
Broad Research Categories	Hazard Characterization
NNI identifier

Funding Information

Country	Canada
Anticipated Total Funding	$86,883.00
Annual Funding	$43,441.50
Funding Source	NSERC
Funding Mechanism	Extramural
Funding Sector	Government
Start Year	2005
Anticipated End Year	2007

Abstract/Summary

Very small objects, such as individual sugar molecules, ions, and sometimes small proteins, can pass into living cells through a variety of different mechanisms. Some molecules can pass directly through a cell’s membrane, others travel through specific protein pores in the membrane, and others are engulfed by the cell (this latter does not occur in bacteria). Semiconductor nanoparticles (quantum dots or QDs) are also known to penetrate into cells, despite being many times larger than most objects typically taken up. Surprisingly, it is not the size of the QDs that determines the efficiency of their entry, but their reactivity. This reactivity is due to the quantum-mechanical nature of the particles and changes qualitatively with particle size, material, and exposure to light and oxygen. The more reactive the particle, the more able it is to enter a cell and to interact with structures inside the cell, such as the nucleus and DNA. This often leads to cell death or to loss of the cell’s ability to reproduce. The mechanisms for QD entry into cells, and the exact factors which make them more or less reactive, are not known. Our work will quantify the interactions of QDs with cell membranes, cellular proteins, DNA, and whole cells with the goal of identifying the exact conditions under which the particles can damage cells. This will result in the design of simple tests for researchers to use that will predict the cellular toxicity of nano-sized materials based upon physical properties such as size and fluorescence. We will also determine whether specific classes of molecules, including DNA molecules, make QDs more reactive and hence more toxic, which will allow for recommendations for handling and disposing of these particles in biological experiments.