Nanostructured polymeric surfaces for biological interfaces

Emil Rosqvist*

*Tämän työn vastaava kirjoittaja

Tutkimustuotos: VäitöskirjatyypitTohtorinväitöskirjaArtikkelikokoelma


In order to manufacture novel synthetic materials for use in biological applications, the continuous interactions over the materials interface must be thoroughly understood. It is difficult to develop all-encompassing descriptions of the multifaceted and dynamic character of these interactions and such conclusions elude scientists to date. Mammalian and bacterial cells react to physico-chemical properties of their surroundings. Such properties include a.o. surface energy, wetting, topography, and stiffness. Using materials with a controlled physico-chemical character, cells can be influenced through controlled interactions. Disparate responses driven by different materials have been observed — such as changes in adhesion, spreading, viability, morphology, division, and phenotype.

In this work different latex polymers were used to produce nanostructured surfaces with a controllable physico-chemical character, which was profoundly parameterised. The intent was to investigate how the character of the surfaces would influence Staphylococcus aureus bacterial biofilms as well as mammalian cells, specifically human dermal fibroblasts (HDF) and cervical cancer cells (HeLa). Cellular viability as well as the content and structure of the extracellular matrix or the biomatrix were used as measures of biological responsivity. In the bacterial studies, the responses of S. aureus to the surfaces were also compared in two different assays.

Surface properties, such as the peak and valley structures, influenced the viability of S. aureus and the polysaccharide contents of the bacterial biomatrix. Furthermore, these biofilms were influenced differently by the surface properties in the different assays. Another novel finding was that surface properties (and assay) can influence the S. aureus surface proteome. The amount of several virulence-associated proteins on the bacterial surface could for the first time be correlated with surface roughness parameters.

Mammalian HDF and HeLa cells responded differently to the surface nanotopography and surface chemistry. The viability of HeLa cells was influenced by e.g. the surface chemical character of the surfaces, but the viability of HDF cells was not influenced. An increasing amplitude of topographical peaks and valleys both increased the HDF viability, but the viability of HeLa cells was primarily benefited by a valley-dominated surface topography.

These surfaces were applied in an affordable, tailorable, paper-based planar diagnostics platform. The processability of the platform was demonstrated by using it both in a materials study and a drug screening study. In the studies, both the material and the drug were applied onto the platform with up-scalable methods. The analysis was done colorimetrically with an office scanner and a custom software. The results proved to be of comparable reliability with studies done in commercial well-plates and analysed with advanced plate readers.

This work shows that by using an extensive selection of surface parameters their individual influence on cells can be decoupled. Further, it shows that significant variations in different bioresponses can be observed when cells are grown on surfaces with nanoscale topographical differences. Such surfaces can be used to develop accessible, reliable and low-cost diagnostics platforms. The knowledge obtained can be used to develop novel materials for bio-applications, e.g. biomedical surfaces, where bacterial and cellular interactions with or via the material, e.g. fomite transmission, must be controlled.
  • Peltonen, Jouko, Valvoja
Painoksen ISBN978-952-12-4122-2
Sähköinen ISBN978-952-12-4123-9
TilaJulkaistu - 2021
OKM-julkaisutyyppiG5 Tohtorinväitöskirja (artikkeli)


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