The current doctoral thesis focused on the development of mussel-inspired antifouling polyglycerol coatings for the prevention of biomaterial-related fouling.
In the first publication of this thesis, a coating based on the combination of mussel-inspired dendritic polyglycerol (MI-dPG) and linear polyglycerol (lPG) was successfully developed. Titanium dioxide (TiO2) was selected as a medically relevant substrate material. The formation and stability of the novel coating were confirmed by means of water contact angle measurements (CA), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Measurements with a quartz crystal microbalance with dissipation monitoring confirmed the protein repelling properties of MI-dPG–lPG. Furthermore, cell culturing experiments showed that the MI-dPG–lPG system successfully reduced the adhesion of human umbilical vein endothelial cells. All results were compared to a similar MI-dPG coating that was post-functionalized with polyethylene glycol (PEG). The lPG-functionalized coating outperformed the PEG-functionalized coating in terms of stability and antifouling performance.
In the second publication of this thesis, the MI-dPG–lPG coating was applied as a blood contacting biomaterial for the reduction of biomaterial-induced thrombosis in ventricular assist devices (VADs). Again, TiO2 was selected as the substrate material, as it is commonly used for the production of VADs. The biocompatibility of the MI-dPG–lPG coating was shown via cell culturing experiments with human adenocarcinomic alveolar basal epithelial cells and chicken fibroblast cells. Additionally, the biocompatibility of the coating was confirmed via complement activation tests. Furthermore, the cell culturing experiments clearly indicated that the MI-dPG–lPG coating prevented cellular adhesion. Most importantly, tests with platelet rich plasma and whole blood showed that the MI-dPG–lPG coating prevented the adhesion and activation of blood platelets under static and medically relevant flow conditions. Again, the results were compared to a MI-dPG coating which was functionalized with PEG. The MI-dPG–lPG system outperformed the MI-dPG–PEG system in terms of antifouling performance and hemocompatibility. Finally, a prototype VAD (kindly provided by Berlin Heart GmbH) was coated with MI-dPG under industrially relevant flow conditions. The successful functionalization of the VAD system with MI-dPG was shown via fluorescence experiments.
In the last publication of this thesis, the MI-dPG coating was utilized as a platform for the direct grafting of dPG from the surface, for the introduction of antifouling surface properties to medically relevant TiO2 and polydimethylsiloxane (PDMS). The successful grafting of dPG from MI-dPG was confirmed by means of CA, XPS, and SEM measurements. The results showed that in the absence of the MI-dPG coating, the dPG grafting process only occurred insufficiently from the TiO2 substrate (i.e., through the hydroxyl moieties present on the surface of TiO2). In case of the PDMS substrate, dPG grafting did not occur in the absence of MI-dPG. Cell culturing experiments showed that upon the grafting of dPG from MI-dPG highly biocompatible but cytophobic surfaces were obtained (> 95% reduction in cell adhesion for both cell types).