Selective functionalization of II-VI semiconductor quantum dots with peptides and integrins of cancer cells for biophotonic applications

Abstract

Nanoscale functionalization of semiconductor quantum dots (SQDs) 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 SQDs such as CdS, and ZnS-capped CdSe SQDs, conjugated with biomolecules such as short peptides and cells are presented. We study CdS SQDs functionalized with peptides specially composed of the following amino acid chains: CGGGRGDS, CGGGRVDS, CGGIKVAV, and CGGGLDV, where R is arginine, D - aspartic acid, S - serine, V - valine, K - lysine and L is Levine. As will be seen the cysteine (C) amino acid links to CdS SQDs via the thiol link, the GGG sequences of glycine (G) amino acid, provide a spacer in the amino acid chain. At the same time 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.