Semiconductors and Biomedical Structures for Nanobiometric Applications

Nanoscale functionalization of semiconductor quantum dots with biomedical structures is promising for many applications and novel studies of intrinsic properties of both constituent systems. Results of our study of structural properties of the nanoscale functionalized colloidal semiconductor quantum dots such as CdS ZnS-capped CdSe, TiO2 functionalized with biomolecules such as short peptides and cells will be presented. The use of semiconductor quantum dots as biotags has emphasized use of the semiconductor luminescence to determine the location where chemically functionalized semiconductor quantum dots bind to a biomedical sample. We study semiconductor quantum dots functionalized with peptides composed of the following amino acid chains: CGGGRGDS, CGGGRVDS, CGGIKVAV, and CGGGLDV, where R is arginine, D is aspartic acid, S is serine, V is valine, K is lysine and L is Levine. The RGDS, RVDS, IKAV, and LDV sequences have selective bonding affinities to specialized transmembrane cellular structures known as integrins of neurons and MDA-MB-435 cancer cells, respectively. We found that the quantum confinement and functionalizing in biomedical environments plays in altering and determining the electronic, optical, and vibrational properties of these nanostructures as well as demonstrated the effectiveness to use semiconductor quantum dots as integrin sensitive biotags.