Date

6-2011

Degree Name

BS in Materials Engineering

Department

Materials Engineering Department

Advisor(s)

Richard Savage

Abstract

Herein is described the procedure of two amphiphilic polymer wrapping techniques that may be employed for obtaining aqueous soluble quantum dots (QDs) for use in biological fluorescent imaging applications. The advent of QDs has led to new nanoscale fluorescent materials that exhibit unparalleled quantum yields (QYs), high resistance to photobleaching, tunable emissions, and
absorption over a large optical range. However, the QD synthesis employed here at Cal Poly to obtain bright, photostable CdSe(ZnS) core(shell) QDs involves the use of organic solvents and surfactants, leading to hydrophobic QDs. Since all of biology relies on aqueous solubility, this hydrophobicity creates a major problem when trying to use QDs for biological imaging applications. One way to overcome this problem is to employ the technique of amphiphilic polymer wrapping to coat
the hydrophobic QDs in an amphiphilic polymer that allows them to disperse in aqueous solutions. This paper describes two procedures for obtaining aqueous soluble QDs here at Cal Poly that fluoresce in the optical range and that can be used for biological imaging at Cal Poly in the future. Both procedures were a success in transferring QDs to an aqueous solvent, but resulted in a 65% decrease in peak emission intensity. Methods of photo- annealing were then used to permanently enhance the QD fluorescence and maintain QD brightness in
aqueous solution.