Optical properties of quantum dot-metal composites and their applications in detection of prostate cancer biomarkers

Abstract

Due to unique optical and electrical properties, such as broad excitation region, narrow emission area, tunable optical properties, strong luminescence, and excellent

photostability compared to conventional organ-ic dyes, luminescent semiconductor quantum dots (QDs) have been utilized in wide applications in biology such as

biological imaging, DNA detection, multiplexing beads, and efficient donors in fluorescence (Forster) resonance energy transfer (FRET) mechanisms. Recently, the QDs-

metal nanoparticle (NP) composites have offered highly promising potential applications in nanotechnology and biotechnology because of their interest-ing properties,

such as fluorescence enhancement and quenching effects. Considerable theoretical and experi-mental effort is being made to understand the mechanisms of the

photoluminescence (PL) enhancement and quenching phenomenon for QDs-metal composites. However, understanding on the mechanism and potential applications of the

fluorescence quenching phenomenon is still very limited. Properties of the QDs-metal com-posites have been performed in a solid state. For real biological

applications, the QDs-metal composites with unique optical properties should be available in a water solution, while there have been only a few research works on the

composites dispersed in a water solution. Even though some research had worked on the optical properties in aqueous solution, it is still not enough to systematically

understand the quenching and enhance-ment mechanisms in our own QDs-metal system. The aims of this research are to gain deep understanding of PL quenching and

enhancement dynamics in QDs-metal composites, and to obtain a new protein chip detection system with high sensitivity and low limit of detection (LOD) by using QDs-

metal composites. The first study in this dissertation is to investigate the fluorescence dynamics of QDs-metal compo-sites. We indicated a systematical study of optical properties, ...