Author: Ge, Qiongying
Title: Air plasma treatment of PDMS : surface physical properties and substrate for cell adhesion
Degree: M.Sc.
Year: 2009
Subject: Hong Kong Polytechnic University -- Dissertations.
Cell culture -- Technique.
Cell adhesion.
Plasma engineering.
Surfaces (Physics)
Department: Department of Health Technology and Informatics
Pages: xiii, 87 leaves : ill. (some col.) ; 30 cm.
Language: English
Abstract: Polydimethylsibxane (PDMS) are widely used as supporting material for cell culturing in medical implants. However, current applications require PDMS to be biocompatibte for cell culturing and easy for processing. The aim of this project is to study the surface properties of PDMS after air plasma treatment and the effects of air plasma modified PDMS on cell adhesion. In this paper, the five groups are PDMS substrates modified by air plasma with different treated time (10s, 30s, 60s, 2min and 5min). Statistic contact angles are measured to evaluate the surface wettability properties change. Then, the treated surfaces are characterized using Scanning Electronic Microscopy (SEM) to observe the changes of surface morphology. Human esophageal squamous epithelial KYSE-30 cancer cells and rat bone marrow derived mesenchymal stem cells (MSC) were seeded onto untreated, treated and negative controlled samples. Cell density, cell morphology and viability were assessed at set time-points. As an effect of the air plasma treatment, the contact angles measured on PDMS surfaces decreased significantly. The treatment time had non-ignorable effect on the results. With increasing air plasma treated time, it has been observed that the PDMS surface has a much lower water contact angle as compared to the hydrophobic, native PDMS surface. Although air plasma treatment caused PDMS become hydrophilic, PDMS substrates could not retain this property over time. SEM analysis showed significant surface morphological changes between the 5min air plasma treated and untreated PDMS. The former surface has considerable cracks rather than untreated PDMS with relatively smooth surface. The data from in vitro assays showed that cell attachment onto negative control surface (TCPS) was significantly higher than those cultured on untreated and air plasma treated PDMS surfaces. However, the data also demonstrated that PDMS surfaces with longer time for air plasma treatment will support better adhesion and spreading for KYSE-30 cell lines than untreated PDMS surfaces. However, this phenomenon was not obvious between the 60s and 2min air plasma treated group which consistent with the result that the contact angles measured immediately after the air plasma treatment between 60s and 2min groups did not have significant difference. The fluorescein diacetate-propidium iodide staining method showed high cell viability on air plasma treated and untreated surfaces. The fluorescence microscopy results indicate that the cell morphology among the different air plasma treated groups and untreated PDMS surfaces were no distinct difference, however, the discrepancy observed from images in a high extent caused by the low observatbn resolution and the low cell density. For five groups with different air plasma treated time, both in the contact angle measurements and the cell adhesion evaluation, the treated effect was increased with the increased air plasma treated time.
Rights: All rights reserved
Access: restricted access

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