Elżbieta Pamuła

Bulk and surface chemical functionalities of type III PAN-based carbon fibres

PAN-based carbon fibres carbonised at relatively low temperature, i.e. type III carbon fibres, were submitted to heat treatment at 2300 °C (GR) or oxidation in nitric acid. The samples were characterised by XPS, FTIR, wetting measurements, gas adsorption, elemental analysis and acid/base titration. While oxidation only slightly affects the nitrogen concentration, it produces an appreciable change in the nature of the chemical functions, namely the conversion of pyridine-type nitrogen and quaternary nitrogen into aliphatic functions. Oxidation treatment modifies all the material constituting the fibre, the oxygen concentration being about 1.5 times higher at the fibre external surface compared with the whole material. Three components (531.2, 532.6 and 533.8 eV) are clearly identified in the oxygen XPS peak, allowing a comparison to be made between the whole material and the external surface regarding chemical species. The acidic groups are mainly carboxyl. Fibres submitted to extensive oxidation also show a high basicity, attributed mainly to calcium carboxylate. Although the acidic and basic groups present in the whole material can be titrated with aqueous solutions, the fibres develop only a very small surface area and no microporosity as determined by krypton adsorption. The material may be viewed as a sponge, collapsed when dry but able to swell in water and developing a high cation-exchange capacity.

FTIR study of degradation products of aliphatic polyesters–carbon fibres composites

Abstract Biodegradable polymer composites based on polylactides and polyglycolides constitute a group of materials characterised by good biocompatibility. They are considered in tissue engineering as scaffolds for cells proliferation and controlled tissue regeneration. Two types of biodegradable polymers possessing different chemical structure, molecular weights and crystallinity degrees and two composite materials made up of them and carbon fibres were analysed in this study. The samples were incubated in aqueous media for 8 weeks and analysed by means of Fourier transform infrared spectroscopy in the attenuated total reflection mode (FTIR-ATR). Infrared spectroscopy enabled identification of degradation products and estimation of the influence of carbon fibres on hydrolytic degradation of analysed polymers. Analysis of the infrared spectra showed that hydrolytic degradation process depends on chemical structure, molecular weight and crystallinity of polymers. Catalytic effect of carbon fibres at the initial stage of polymer degradation was observed. Further degradation is dependent on the properties of polymer.

Resorbable polymeric scaffolds for bone tissue engineering: The influence of their microstructure on the growth of human osteoblast-like MG 63 cells

Degradable three-dimensional porous scaffolds applicable as cell carriers for bone tissue engineering were developed by an innovative solvent casting/particulate leaching technique from poly(L-lactide-co-glycolide) (PLG). Three types of PLG scaffolds were prepared, and these had the same high porosity (83%) but increasing diameter of the pores (180-200 microm, 250-320 microm, and 400-600 microm) and increasing pore interconnectivity. The colonization of the scaffolds with human osteoblast-like MG 63 cells was then studied in vitro in a conventional static cell culture system. The number of cells growing on the scaffolds on days 1 and 7 after seeding was highest in the material with the largest pore diameter, but on day 15, the differences among the scaffolds disappeared. Confocal microscopy revealed that on day 1 after seeding, the cells penetrated to a depth of 490 +/- 100 microm, 720 +/- 170 microm, and 720 +/- 120 microm into the scaffolds of small, medium, and large pore size, respectively. Incorporation of bromodeoxyuridine into newly synthesized DNA and the concentration of vinculin, beta-actin, osteopontin, and osteocalcin in cells on the scaffolds of all pore sizes were similar to the values obtained on standard tissue culture polystyrene, which indicated good biocompatibility of the scaffolds. These results suggest that all scaffolds could serve as good carriers for bone cells, although the quickest colonization with cells was found in the scaffolds with the largest pore diameter from 400 to 600 microm.

Porous polymer/hydroxyapatite scaffolds: characterization and biocompatibility investigations

Poly-lactic-glycolic acid (PLGA) has been widely used as a scaffold material for bone tissue engineering applications. 3D sponge-like porous scaffolds have previously been generated through a solvent casting and salt leaching technique. In this study, polymer–ceramic composite scaffolds were created by immersing PLGA scaffolds in simulated body fluid, leading to the formation of a hydroxyapatite (HAP) coating. The presence of a HAP layer was confirmed using scanning electron microscopy, energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy in attenuated total reflection mode. HAP-coated PLGA scaffolds were tested for their biocompatibility in vitro using human osteoblast cell cultures. Biocompatibility was assessed by standard tests for cell proliferation (MTT, WST), as well as fluorescence microscopy after standard cell vitality staining procedures. It was shown that PLGA–HAP composites support osteoblast growth and vitality, paving the way for applications as bone tissue engineering scaffolds.

In vitro response of macrophages to a new carbon-polylactide composite for the treatment of periodontal diseases

The purpose of the study was to examine the response of macrophages and the concentration of selected released cytokines following contact with a new carbon-polylactide composite. The macrophages were grown on samples of the materials and on each of its components separately. Viability of the cells as well as concentrations of interleukins IL-6, IL-10, IL-12 and TNF-alpha were then determined. Some differences in the viability of the cells were demonstrated. They varied according to the kind of material used. After incubation with the serum, the composite and its components induced the release of IL-6, IL-12 and TNF-alpha which did not differ significantly from one another.

Ocena wybranych biomateriałów do rekonstrukcji perforacji przegrody nosa

INTRODUCTION The septal nasal perforation is an important problem for the laryngologists and plastic surgeons. The reasons of septal nasal perforations are injuries, neoplasm, self-mutilation, chronic rhinitis, allergy, Wegener granuloma, sarcoidosis, tuberculosis, toxic metals (arsenic, chrome), some drugs (steroids), narcotizing agents (cocaine) and complications after endoscopic and septal nasal operations. The surgical treatment, especially in the cases of large septal perforation, is often difficult because of the atrophy of nasal mucosa and lack of suitable material for reconstruction. In the surgical treatment many of methods and reconstructive materials have been used. The following autogenous tissues were used in the reconstruction of septal perforation: alloderm, temporal fascia, septal and auricle cartilage, cranial periosteum, perichondrium, ethmoidal and hip bone. The defect of such materials is progressive resorption. For many years the suitable synthetic material for septal nasal reconstruction has been searched for. Among the biomaterials the following have been used without success: Dacron, porous polyethylene, dolomite, bioglass. The rejection of synthetic material was the reason of failure. The aim of our study was to evaluate two different biomaterials with proper mechanical and biological features for nasal cartilage replacement. MATERIAL AND METHODS We studied two types of biomaterials: biostable terpolymer PTFE/PVDF/PP and resorbable copolymer of glycolide and L-lactide (PGLA). The pilot studies were performed on two experimental animals (rabbits). The animals were operated in the general anesthesia. The biomaterials were implanted in the rabbit auricular cartilage because of its similarity to the septum and easy surgical access. Subperichondrically 1 x 1 cm fragment of the cartilage was removed. This fragment was then replaced with the biomaterial. The rabbits were painlessly sacrificed after 4 months of observation. RESULTS A very good integration of PGLA implant with auricular cartilage was observed. In the histological examination the lack of excessive inflammatory reaction as well as no cartilage necrosis were observed. CONCLUSIONS 4 months after implantation of PGLA in the rabbit auricular cartilage very good macroscopic and histological results were achieved.Summary Introduction The septal nasal perforation is an important problem for the laryngologists and plastic surgeons. The reasons of septal nasal perforations are injuries, neoplasm, self-mutilation, chronic rhinitis, allergy, Wegener granuloma, sarcoidosis, tuberculosis, toxic metals (arsenic, chrome), some drugs (steroids), narcotizing agents (cocaine) and complications after endoscopic and septal nasal operations. The surgical treatment, especially in the cases of large septal perforation, is often difficult because of the atrophy of nasal mucosa and lack of suitable material for reconstruction. In the surgical treatment many of methods and reconstructive materials have been used. The following autogenous tissues were used in the reconstruction of septal perforation: alloderm, temporal fascia, septal and auricle cartilage, cranial periosteum, perichondrium, ethmoidal and hip bone. The defect of such materials is progressive resorption. For many years the suitable synthetic material for septal nasal reconstruction has been searched for. Among the biomaterials the following have been used without success: Dacron, porous polyethylene, dolomite, bioglass. The rejection of synthetic material was the reason of failure. The aim of our study was to evaluate two different biomaterials with proper mechanical and biological features for nasal cartilage replacement. Material and methods We studied two types of biomaterials: biostable terpolymer PTFE/PVDF/PP and resorbable copolymer of glycolide and L-lactide (PGLA). The pilot studies were performed on two experimental animals (rabbits). The animals were operated in the general anesthesia. The biomaterials were implanted in the rabbit auricular cartilage because of its similarity to the septum and easy surgical access. Subperichondrically 1 x 1 cm fragment of the cartilage was removed. This fragment was then replaced with the biomaterial. The rabbits were painlessly sacrificed after 4 months of observation. Results A very good integration of PGLA implant with auricular cartilage was observed. In the histological examination the lack of excessive inflammatory reaction as well as no cartilage necrosis were observed. Conclusions 4 months after implantation of PGLA in the rabbit auricular cartilage very good macroscopic and histological results were achieved.

Rekonstrukcja tkanki chrzęstnej biomateriałami polimerowymi – wczesne wyniki makroskopowe i histologiczneCartilage tissue reconstruction by the polymer biomaterials – early macroscopic and histological results☆

Summary Introduction The surgical treatment of large cartilage defects in the region of head and neck is often impossible because of the atrophy of surrounding tissues and lack of suitable material for reconstruction. In the surgical treatment many of methods and reconstructive materials have been used. For many years the suitable synthetic material for the cartilage defects reconstruction has been searched for. The aim of the study was to evaluate two different biomaterials with proper mechanical and biological features for the cartilage replacement. Material and methods Two type of biomaterials in this study were used: resorbable polymer – poly(L-lactide-co-glycolide) (PLG) acting as a supportive matrix. A thin layer of sodium hyaluronate (Hyal) was also deposited on the surface as well in the pore walls of PLG scaffolds in order to provide biologically active molecules promoting differentiation and regeneration of the tissue. The studies were performed on the 50 animals – rabbits divided into 2 groups. The animals were operated in the general anaesthesia. The incision was done along the edge of the rabbits auricle. Perichondrium and cartilage of the auricle on the surface 4 × 3 cm were prepared. Subperichondrically 1 × 1 cm fragment of the cartilage was removed by the scissors. This fragment was then replaced by the biomaterials: PLG in first group of 25 rabbits and PLG-Hyal in second group 25 rabbits. The tissues were sutured with polyglycolide Safil® 3–0. The animals obtained Enrofloxacin® for three days after the operation. Then 1, 4 and 12 weeks after the surgery the animals were painlessly euthanized by an overdose of Morbital®. Implants and surrounding tissues were excised and observed macroscopically and using an optical microscope. Results In all the observation periods we observed proper macroscopic healing process of biomaterials. We didn’t state strong inflammatory process and necrosis around the implanted biomaterials. Conclusions The histological and macroscopic examinations indicated that both materials developed in this study have properties similar to cartilaginous tissue and seem to be good for her restoration. Although the quickest tissue regeneration was found after implantation of PLG-Hyal.

Rekonstrukcja tkanki chrzęstnej biomateriałami polimerowymi – wczesne wyniki makroskopowe i histologiczne ☆

Summary Introduction The surgical treatment of large cartilage defects in the region of head and neck is often impossible because of the atrophy of surrounding tissues and lack of suitable material for reconstruction. In the surgical treatment many of methods and reconstructive materials have been used. For many years the suitable synthetic material for the cartilage defects reconstruction has been searched for. The aim of the study was to evaluate two different biomaterials with proper mechanical and biological features for the cartilage replacement. Material and methods Two type of biomaterials in this study were used: resorbable polymer – poly(L-lactide-co-glycolide) (PLG) acting as a supportive matrix. A thin layer of sodium hyaluronate (Hyal) was also deposited on the surface as well in the pore walls of PLG scaffolds in order to provide biologically active molecules promoting differentiation and regeneration of the tissue. The studies were performed on the 50 animals – rabbits divided into 2 groups. The animals were operated in the general anaesthesia. The incision was done along the edge of the rabbits auricle. Perichondrium and cartilage of the auricle on the surface 4 × 3 cm were prepared. Subperichondrically 1 × 1 cm fragment of the cartilage was removed by the scissors. This fragment was then replaced by the biomaterials: PLG in first group of 25 rabbits and PLG-Hyal in second group 25 rabbits. The tissues were sutured with polyglycolide Safil® 3–0. The animals obtained Enrofloxacin® for three days after the operation. Then 1, 4 and 12 weeks after the surgery the animals were painlessly euthanized by an overdose of Morbital®. Implants and surrounding tissues were excised and observed macroscopically and using an optical microscope. Results In all the observation periods we observed proper macroscopic healing process of biomaterials. We didn’t state strong inflammatory process and necrosis around the implanted biomaterials. Conclusions The histological and macroscopic examinations indicated that both materials developed in this study have properties similar to cartilaginous tissue and seem to be good for her restoration. Although the quickest tissue regeneration was found after implantation of PLG-Hyal.