Oberflächenmodifizierung von Polyvinylidenfluorid zur Minimierung der Proteinadsorption

The goal of this work was the development of surface coatings, which reduce or completely prevent a nonspecific protein accumulation and the subsequent cell adhesion and thus improve the biocompatibility of the material. The polyvinylidene fluoride (PVDF) was used as the base polymer. To provide PVDF surfaces with protein-rejecting layers functional groups had to be created on the surface first. The first procedure was performed by the chemical vapour deposition (CVD) polymerisation of 4-amino-[2.2]-paracyclophanes to amino-poly-p-xylylene (amino-ppx) on the PVDF surfaces. The second procedure was carried out by the surfaces activation by means of an argon plasma following a graftcopolymerisation of acrylic acid. The successful coating of the PVDF surfaces was proved by means of attenuated total reflection infrared spectroscopy (IR-ATR) and X-ray photoelectron spectroscopy (XPS). In further reaction steps the functionalised PVDF surfaces were modified with different polymers on polyethylene glycol or polysaccharide basis. These polymers show a low non-specific interaction with proteins and cells. In addition to the variation of the chain lengths of the mPEGs, different coupling conditions were applied (temperature and potassium sulfate concentration) to achieve different coupling densities. Polyethylenimine (PEI) was coupled to the carboxyl groups of the PAAc-layer. By this procedure a higher amino group density was obtained compared to the CVD method. These primary aliphatic amino groups served for the following covalent coupling of mPEG-aldehydes. The produced PEI layer was proven by means of XPS. In addition, the carboxymethylied polysaccharides dextran (COOH-DEX) and hydroxyethylstarch (COOH-HES) were immobilised at PVDF-PAAc-PEI surfaces. A further possibility for the immobilisation of PEGs on PVDF-PAAc surfaces without a PEI intermediate layer exists in the coupling of aminoterminared mPEGs. Additionally, in comparison to these long PEG-chains, the influence of the substantial shorter ethyloxide units of the 2-(2-Aminoethoxy)-ethanol (AEE) was examined for the protein adsorption. In a further investigation, the adsorption behaviour of the proteins insulin, lysozym and fibronectin was examined. The adsorption behaviour of both lysozym and insulin respectively, was examined by means of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) in the surface mode on PVDF surfaces before and after modification. Neither adsorbed lysozym nor adsorbed insulin were detected in the Surface-MALDI-spectra of the PVDF-PAAc-PEI surfaces, which were modified under cloud point conditions. The adsorption behaviour of fibronectin and insulin was analysed by means of Enzymes Linked Immunosorbent Assay (ELISA). For the quantitative determination of the adsorbed amount of fibronectin, lysozym and insulin these proteins were marked with radioactive 125Iod and adsorbed on the surfaces. Finally, the cell rejecting behaviour of the modified PVDF surfaces was estimated by means of in-vitro cell tests. The PVDF surfaces, which were modified with both mPEGs under cloud point conditions, and with carboxymethylied polysaccharides respectively, showed an obvious cell rejecting behaviour. From these results is concluded that a successful rejection of complex protein mixtures and the cells can be obtained only by strongly hydrophilic and electrostatic neutral surfaces. In addition, the grafting density as well as the chain length of the polymer molecules are also of a great importance.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Ademovic, Zahida

Contributors dc:contributor

• Höcker, Hartwig

• info:eu-repo/classification/ddc/540
• Chemie
• PVDF
• Oberflächenmodifizierung Proteinadsorption

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-120655%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:58823