Antimicrobial materials with improved efficacy dedicated to large craniofacial bone defects after tumor resection.

The research was focused on alternative treatment techniques, separating immediate and long-term reconstruction stages. The work involved development of ceramic materials dedicated to reconstruction of the temporomandibular joint area. They were based on alumina (aluminum oxide) and characterized by varying porosities. A broad spectrum of studies was conducted to test the proposed material and determine its suitability for mandibular reconstruction. They compared the effects of substrate properties of ceramic materials in terms of biocompatibility, microbiology and systemic toxicity in in vivo studies. Finally it was concluded that Alumina LithaLox 350D is best suited for jawbone implants.

Antibacterial Optimization of Highly Deformed Titanium Alloys for Spinal Implants.

The goal of the work was to develop materials dedicated to spine surgery that minimized the potential for infection originating from the transfer of bacteria during long surgeries. The bacteria form biofilms, causing implant loosening, pain and finally, a risk of paralysis for patients. Our strategy focused both on improvement of antibacterial properties against bacteria adhesion and on wear and corrosion resistance of tools for spine surgery. Further, a ~35% decrease in implant and tool dimensions was expected by introducing ultrahigh-strength titanium alloys for less-invasive surgeries. The tested materials, in the form of thin, multi-layered coatings, showed nanocrystalline microstructures. Performed direct-cytotoxicity studies (including lactate dehydrogenase activity measurement) showed that there was a low probability of adverse effects on surrounding SAOS-2 (Homo sapiens bone osteosarcoma) cells. The microbiological studies (e.g., ISO 22196 contact tests) showed that implanting Ag nanoparticles into Ti/TixN coatings inhibited the growth of E. coli and S. aureus cells and reduced their adhesion to the material surface. These findings suggest that Ag-nanoparticles present in implant coatings may potentially minimize infection risk and lower inherent stress.

Patient specific implants for jawbone reconstruction after tumor resection.

In case of benign and malignant tumours affecting the maxillofacial region, the resection of jawbone reflects the standard therapy in more than 5.000 cases per year within the European Union. The resulting large bone defects lead to scarred, mangled facial appearance, loss of mastication and probably speech, requiring aesthetic and functional surgery as a basis for physical and physiological rehabilitation. Although autologous vascularized bone autografts reflect the current golden standard, the portion of bone available for the procedure is limited and subsequent high-dose anti-cancer chemo-/radiotherapy can lead to local tissue necrosis. Autologous vascularized bone from fibular or iliac-crest autografts is current golden standard in jawbone resection post-treatment, however, the portion of transplantable bone is limited and subsequent high-dose anti-cancer chemo-/radiotherapy often results in tissue necrosis Our research focuses on alternative treatment techniques: tissue reconstruction via novel patient-specifically manufactured maxillofacial implant that stimulates bone tissue growth. The planned neoformation of vascularized bone in such implants within the patient's own body as "bioreactor" is the safest approach in tissue engineering. The works described herein included the design of the metallic substrate of the implant with the use of computed tomography basing on real patients scans and then 3D-printing the substrates from the Ti6Al7Nb powder. The metal core was then evaluated in terms of structural characteristic, cytotoxicity and gene expression through the in vitro tests. Further experiments were focused on fabrication of the biocompatible coating for outer surface of the bone implant that would enhance the healing process and accelerate the tissue growth. Functional polymeric granulate dedicated for osteoconductive, osteoinductive and osteogenesis properties were elaborated. Another approach including the coating for the implant surface with two-phase biocompatible layer including polymeric microspheres and hydrogel carrier, which would provide long-time release of bone and cartilage growth factors around the implant were also done. The polymeric granulate containing ßTCP improved bone cells growth, but it some modification has to be done in order to improve structural pores to ensure for better osteoconductivity. The biocompatible coating including PVP hydrogel and polymeric microspheres is still in the development process.

The interaction of laser radiation with tissue in the aspect of generating the process of decellularization in the preparation of animal origin autologous tissue.

PURPOSE: The aim of the work was to create an appropriate substrate for organ transplantation using bioactive tissue-based scaffold populated by cells of the graft recipient. The purpose of the modeling was to investigate the mechanical effects of wave loading of aortic and pulmonary tissue material. METHODS: The biological properties of tissues of aortic and pulmonary valves were modified by the process of decellularization. The host cells were removed by various physical methods with focus on minimal degradation of the extracellular matrix. Thus, the decellularization process was controlled by histological methods. The tissue decellularization process was simulated by finite element modelling. RESULTS: The mechanical results represented by a displacement at the center of the sample were coherent and the heterogeneity of the distribution of the caves on the surface of the samples was confirmed, both by experiment and in the simulation by the alternate occurrence of local minima and maxima. The latter results from the uneven removal of cells from the effect of the wave causing decellularization were also predicted by the numerical model. Laser radiation had a destructive effect on the components of the extracellular matrix (e.g., collagen and elastic fibers), mainly depending on the fluence and number of pulses in a single exposure. CONCLUSIONS: The differences between the valve tissue materials were shown, and the impact of the process of decellularization on the properties of the tissues was analyzed. It should be emphasized that due to low absorption and high scattering, laser radiation can deeply penetrate the tissue, which allows for effective decellularization process in the entire volume of irradiated tissue.

Lecithin suspensions for electrophoretic deposition on stainless steel coatings.

Lecithin is a mixture of phospholipids (PLs) that are found in living organisms. It gained the interest as a bio- and hemocompatible modifying agent for biomaterials. In this paper, we focused on the elaboration of a simple and well-described technology of metals coating with low-cost substance that could be useful in biomaterials industry. We studied the utility of lecithin suspension for stainless steel coating by electrophoretic deposition method. Our goal was to find a relationship between the conditions of lecithin suspension preparation, obtained suspension properties (vesicles size and structure, zeta potential, electrophoretic mobility) and lecithin coating features (topography, roughness). We found that final pH value, zeta potential and electrophoretic mobility of lecithin suspensions were not altered by initial solution pH value. However, the presence of hydrated Na+ ions forced forming of large multi-layered vesicles. We obtained uniform lecithin coatings with the use of electrophoretic deposition, which has a great potential to be used in a large scale.