Einfluss der Materialvorbehandlung und Prozessparameter auf die Eigenfluoreszenz von spritzgegossenen Cyclo Olefin Polymer Bauteilen

Research output: ThesisMaster's Thesis

Organisational units

Abstract

For many years, fluorescence-based analytics has established itself as a reliable tool in many areas of the life sciences, such as medicine, chemistry or biology. It is used for the diagnosis of diseases, monitoring of therapies or general identification of molecules. However, because of the ever-increasing demands placed on products coupled with high-cost pressures, not only have analytical methods evolved, but so has the sensitivity of optical detection methods. Only low concentrations of the analyte are now required, while the usually inherently weak signal of fluorescence should be precisely detected. Meanwhile, the formats of microarrays also evolved, becoming smaller and more diverse. These carrier structures must be able to withstand the process of analysis, even under high temperatures and the influence of chemicals, while at the same time being cheap and precise to be produced in large numbers under the strict requirements of medical regulations. The material itself must not exhibit any interfering background fluorescence, which would hinder the detection of the actual fluorescence signals of the analysis. In the modern production of microarrays, the material class of cyclo olefin polymers therefore plays a major role. Their optical and mechanical properties make them a popular plastic to produce biochips, lab-on-a-chip and similar applications. Due to their basic chemical structure, they have high transparency and low fluorescence and can be formed cost-effectively by injection molding. Nevertheless, increased fluorescence values have already been observed on products of cyclo olefin polymers after processing the material. This increase is attributed to degradation products of the material, which can be caused by thermal or mechanical stresses that the material experiences during processing. The aim of this work was to systematically investigate the influences of processing on fluorescence. To this end, both the material preparation in terms of material drying and the injection molding process were examined by means of statistical experimental design. For this purpose, the material was dried, injection molded in disc format, and the discs were subsequently measured using a confocal laser fluorescence scanner. It was shown that the type of processing was related to the fluorescence of the material and the product. In addition to the method of drying, the cylinder temperature was found to have the greatest influence on the fluorescence of the final product within the injection molding parameters. Gentle drying under a nitrogen atmosphere as well as gentle melting in the cylinder of the injection molding machine can reduce oxidation and degradation, which accordingly leads to a lower increase in fluorescence. It was also shown that variations within different material batches are of great importance.

Details

Translated title of the contributionInfluence of material preparation and process parameters on the intrinsic fluorescence of injection molded cyclo olefin polymer parts
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
Supervisors/Advisors
Award date31 Mar 2023
DOIs
Publication statusPublished - 2023