Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Physics

Supervisor(s)

Prof. Silvia Mittler

Abstract

Remarkable developments and successes were witnessed in the fabrication and implementation of optical sensors based on localized surface plasmon resonance (LSPR) for the investigation of chemical and biological material quantities and to detect lethal diseases such as cancer in early stages. Gold nanoparticles (AuNPs) are ideal candidate for sensing purposes due to their chemical stability, ease of surface functionalization and strong LSPR in the visible range. Although there are several designs of sensors published, most of them are still limited to small scale research laboratory use partly due to their high cost of fabrication and waste management, in particular critical for solution based LSPR sensors. Sensors implementing immobilized AuNPs show decreased impact in waste management as they are strongly attached to the surface. In addition, sensors made from polymers are less expensive, mass producible and easier to handle in comparison to brittle glass sensors. We report on the reproducible fabrication of chemically stable surface immobilized AuNPs grown via organometallic chemical vapor deposition (OMCVD) on polystyrene (PS). Oxygen plasma and UV ozone treated PS samples depict enhanced amounts of polar –OH groups allowing for nucleation and growth of AuNPs. The optimum plasma treatment conditions, the largest shifts in the LSPR curves and the bulk sensitivity of the OMCVD grown AuNPs are discussed. It was found that the bio-sensing limit of detection of the grown AuNPs for streptavidin binding to biotin was ~ 10 ng/ml. In order to make this sensor applicable for clinical purposes, the sensitivity needs to be enhanced by building a polymer channel waveguide carrying AuNPs and increasing the interaction between the sample and the probing beam in future.


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