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Haifa Al-Dubai1, Gisela Pittner1, Fritz Pittner1, Franz Gabor21Max F Perutz Laboratories, Department of Biochemistry, University of Vienna, Vienna, Austria; 2Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Life Sciences, University of Vienna, Vienna, AustriaAbstract: Feasibility studies have been carried out for development of a biocompatible coating of medical implant materials allowing the binding of biodegradable drug-delivery systems in a way that their reloading might be possible. These novel coatings, able to bind biodegradable nanoparticles, may serve in the long run as drug carriers to mediate local pharmacological activity. After biodegradation of the nanoparticles, the binding sites could be reloaded with fresh drug-delivering particles. As a suitable receptor system for the nanoparticles, antibodies are anchored. The design of the receptor is of great importance as any bio- or chemorecognitive interaction with other components circulating in the blood has to be avoided. Furthermore, the binding between receptor and the particles has to be strong enough to keep them tightly bound during their lifetime, but on the other hand allow reloading after final degradation of the particles. The nanoparticles suggested as a drug-delivery system for medical implants can be loaded with different pharmaceuticals such as antibiotics, growth factors, or immunosuppressives. This concept may enable the changing of medication, even after implantation of the medical device, if afforded by patients’ needs.Keywords: antibody immobilization, biocompatible coating, chitosan nanoparticles, drug targeting, medical device

Haifa Al-Dubai1, Irene Lichtscheidl2, Martina Strobl1, Gisela Pittner1, Fritz Pittner11Department of Biochemistry, Max F Perutz Laboratories, University of Vienna, Vienna, Austria; 2Institute of Cell Imaging and Ultrastructure Research, Vienna, AustriaAbstract: This study focuses on the development of a sensitive and simple cluster-linked immunosorbent assay (CLISA) using gold colloidal cluster labeling for determination of proteins such as antigens (Ags) or antibodies (Abs). Abs for detection can be labeled with gold colloid clusters (GCCs). The Fc domain of the Abs binds to the clusters, and the Fab domain to the Ag on a nitrocellulose membrane or a microtiter plate as a support for dot-blotting. The signal of positive interaction between GCC-labeled Abs and its dotted Ag is detectable by the naked eye and can be quantified by comparison to a color scale prepared from a dilution series of known sample concentrations. The colored reaction product is stable for prolonged periods and does not fade, making this method a simple, fast, and convenient means for detection of Ag or Ab biorecognitions and an alternative to enzyme-linked immunosorbent assay. Several interactions between different Ags or Abs (eg, ß-lactoglobulin) and solutions avoiding gold colloidal cluster flocculation (eg, using protein G) were studied. CLISA was tested for other analytical purposes such as detection of IgEs in patients’ sera.Keywords: ELISA, allergen, patient sera, CLISA, immunoassay, ß-lactoglobulin