The soft-tissue response to implants of chitosan foils

The objective of our in vivo study was to investigate the biocompatibility of polymer foils enriched with chitosan. Methods: three types of chitosan: non-modified(jp), and modified with montmorillonite K5 and montmorillonite K10 (p2-p3) were prepared. The in vivo studies were carried out using the rat soft tissues as a model. Small pieces of foils (2mm x 4mm)used in the experiment were sterilized by UV radiation. Next they were implanted under sterile conditions into the gluteus muscle of adult male outbred Wistar rats. Each animal received two implants: the modified foil into the right muscle, and the unmodifiedfoil used as a control into the left one. All procedures were conducted in sterile conditions and under anaesthesia. Animals were anesthetized with intraperitoneal injection of xylazine and ketamine (Biowet Puławy, Poland). Skin in the site of surgery was shaved and disinfected, and a small incision was made in the gluteus muscle. Equal pieces of foils were inserted into the such created pouch. The muscle and skin wounds were closed with 5/0 PDSII (polydioxanone) monofilament absorbable sutures (Ethicon Ltd., UK). All animals survived the surgery. No wound healing complications were observed after the surgery. The animals were maintained under standard conditions with free access to food and water. After 7, and 30 days from the surgery, at each time point 12animals were sacrificed. Tissue specimens containing the implanted materials were excised and immediately frozen in liquid nitrogen. Next they were cut into 8μm thick slides in a Shandon cryostat (Thermo-Scientific, UK) at -22°C. Obtained slides were investigated through histological and histochemical methods to estimate the intensity of inflammation, production of collagen, and metabolic activity of connective and muscle tissues surrounding implant. In order to estimate the effect of the implants on the metabolic state of surrounding tissues, activities of the marker metabolic enzymes: cytochrome c oxidase, and NADH dehydrogenase were examined. The activity of acid phosphatase was used to assess the extent of inflammation around the implants. The presence and thickness of fibrous capsule around the implants were estimated on slides stained by van Gieson’s method. Results: Differences between non-modified and modified with chitosan materials were not manifested in short, 7- and 30 days series. The activities of mitochondrial oxidative enzymes, cytochrome c oxidase and NADH dehydrogenase, in muscle fibres in close proximity to the implants were slightly lower than in those further away. Probably one month was too short period to obtain the whole recovery after the surgery. At the same time the process of regeneration seemed to be intense: numerous regenerating muscle fibres infiltrated the granulation tissue around the implanted foils were observed The inflammation respone was visibly lower in 30days series compared to7days ones what indicate that the inflammation was evoked in higher degree by surgery than by the presence of the implanted materials. The fibrous capsule around foils was thin or not present at all – there were places where pieces of foils were in direct contact with the muscle tissue. After one month experiment there were no signs of degradation of materials. The experiment has been continued to compare abilities of biomaterials in long term series. Conclusion: The regeneration and enzymic activity of muscle tissue together with the lack of continuous fibrous capsule suggest that the materials used in our study are biocompatibile and are suitable for the treatment of tissue injury

The effect of titanium alloy modified with a-C:N:H and a-SICX_{X}NY_{Y}(H) coatings on adhesion and immune response of human osteoblast-like MG-63 cells

The study was conducted in order to determine the effects of modified titanium alloy (Ti-6Al-4V) surfaces on the biological response of a human osteoblast-like cell line. MG-63 cells were cultured on disk-shaped Ti-alloys: unmodified, and covered with a-C:N:H or a-SiCxNy(H) layers. Interactions between materials and cells were examined through determination of cells adhesion and secretion of cytokines involved in the development of immune response

Composite electrospun membranes stimulate mineralization in bone cell culture

Biodegradowalne nanowłókniste membrany poddano badaniom in vitro, pozwalającym na ocenę stopnia różnicowania się i mineralizacji komórek kostnych w obecności potencjalnych podłoży tkankowych. Przedstawione badania oceniają wpływ mikrostruktury i składu chemicznego wytworzonych podłoży na przyczepność, proliferację i morfologię osteoblastów (NHOst). Badania procesu mineralizacji i aktywności ALP pozwoliły na ocenę procesu różnicowania się komórek.A biodegradable nanofibrous nonwoven membranes were analyzed in vitro as potential scaffolds for differentiation and mineralization of bone cells. In this study we investigate the effects of electrospun membranes microstructure and chemical composition on attachment, proliferation, and morphology of human NHOst osteoblasts. Mineralization process and ALP activity were studied to estimate the cells differentiation

Bioactive nanocomposite PLDL/nano-hydroxyapatite electrospun membranes for bone tissue engineering

New nanocomposite membranes with high bioactivity were fabricated using the electrospinning. These nanocomposites combine a degradable polymer poly(L/DL)-lactide and bone cell signaling carbonate nanohydroxyapatite (n-HAp). Chemical and physical characterization of the membranes using scanning electron microscopy, Fourier transform infrared spectroscopy and the wide angle X-ray diffraction evidenced that nanoparticles were successfully incorporated into the fibers and membrane structure. The incorporation of the n-HAp into the structure increased significantly the mineralization of the membrane in vitro. It has been demonstrated that after a 3-day incubation of composite membrane in the Simulated Body Fluid a continuous compact apatite layer was formed. In vitro experiments demonstrated that the incorporation of n-HAp significantly improved cell attachment, upregulated cells proliferation and stimulated cell differentiation quantified using Alkaline Phosphatase and OsteoImage tests. In conclusion, the results demonstrated that the addition of n-HAp provided chemical cues that were a key factor that regulated osteoblastic differentiation

Middle ear prosthesis with bactericidal efficacy : in vitro investigation

Materials used in ossicular replacement prostheses must possess appropriate biological properties, such as biocompatibility, stability, no cytotoxicity. Due to the risk of infection (otitis media and chronic otitis media), it is desirable to use an antibacterial agent for illness prevention during the ossicular reconstruction. The goal of this work was to observe biological properties of a new composite prosthesis made of ABS containing silver nanoparticles (AgNPs 45T). Samples for biological tests and then a prototype of middle ear prosthesis were prepared using injection moulding and extrusion techniques. In vitro experiments were carried out to assess bactericidal efficacy against Staphylococcus aureus and Pseudomona aeruginosa standard strains, cell proliferation, viability and cytotoxicity, using Hs680.Tr. fibroblast cells. Surface parameters of the samples were evaluated, including roughness and wettability. The silver ions were continually released from the polymer in aqueous solution. The silver ions release was measured as increasing with time and concentration of the silver nanoparticles in the polymer matrix. No cytotoxicity effect was observed, while bactericidal efficacy was noticed for silver nanoparticles. The roughness studies showed an increase in roughness for the samples with silver nanoparticles. All polymer and composite materials containing silver nanoparticles showed hydrophilic properties. The composites were found to release silver ions at a concentration level capable of rendering the antimicrobial efficacy even with the lowest concentration of silver nanoparticles in the material. Our results demonstrate that middle ear prosthesis made of polymer and silver nanoparticles may eliminate bacteria during inflammation in the middle ear