Raman spectroscopy and the material study of nanocomposite membranes from poly(ε-caprolactone) with biocompatibility testing in osteoblast-like cells.

Modern medical treatment can be improved by nanotechnology methods for preparing nanocomposites with novel physical, chemical and biological properties. The materials studied and analysed as membranes were produced from poly(ε-caprolactone) (PCL), which contained identical amounts of nano-additives, either montmorillonite (MMT) or functionalized multi-walled carbon nanotubes (MWCNT-f), while the reference membranes were obtained from unmodified PCL. In addition to the conventional methods used in the study of materials for medical purposes such as DSC, contact angle measurements, surface topography, Raman spectroscopy was also applied. Raman microspectroscopy can decode the phenomenon that occurs in the polymer in contact with the nanoparticles. Besides identifying the vibrations of certain functional groups, the calculation of crystallinity parameters is also possible, by which the most intense interactions within the nanocomposites can be analysed. The Raman studies indicate that each of the nano-additives reacts differently with the polymer matrix, which results in material properties that influence its biological properties. MWCNT-f interacts preferentially with the oxygen-containing groups, and particularly with the backbone regions in the vicinity of the single CO bond. The human osteoblast-like MG-63 cells, cultured on the PCL/MWCNT-f membrane for three days, show almost 100% viability.

Micro-imaging of implanted scaffolds using combined MRI and micro-CT.

RATIONALE AND OBJECTIVES: Thanks to the advanced studies in biomaterial engineering a panoply of polymers can be used to manufacture porous scaffolds for bone tissue regeneration. Suitability of the scaffold for its purpose is determined by factors like size of the pores, its orientation and shape, as well as biocompatibility of the material. Even though a variety of analysis methods is available for in vitro studies, investigating the process of bone reconstruction on implanted scaffold meets with difficulties. METHODS AND MATERIALS: Polylactide porous sponges imbued in hydroxyapatite were implanted into long bones of white New Zealand rabbits for 3 months. The bones obtained from the animals were subjected to MRI and µCT imaging. The obtained images were subsequently fused together. RESULTS AND CONCLUSIONS: Combined MRI and µCT resulted in high resolution diagnostic images which allow for: implant positioning, inflammation divulgement, rating degree of implant resorption, observation of newly formed trabeculae, texture analysis and other quantitative measurements.

Spectroscopic studies of electrophoretically deposited hybrid HAp/CNT coatings on titanium.

Carbon nanotubes deposited on the surface of the metal can be used in a wide variety of applications for modern medicine including: sensors and sensor array devices, electrodes for neural system stimulation, scaffolds for improved healing process for bone defects. Additionally it is debated if deposited on the surface of e.g. endoprosthesis, CNT coating can significantly increase the strength of the tissue/bone joint and stimulate a fast integration of the implant and the tissue. The aim of this paper is the analysis of the electrophoretically deposited nanocomposite coating made of hydroxyapatite nanoparticles and carbon nanotubes on the surface of titanium. The paper concentrates on the analysis of the layer's structure and its bioactivity properties. The nanocomposite films were investigated using Raman Spectroscopy as well as AFM and SEM microscopy. The measurements were conducted at every stage of layer preparation and after bioactivity test. Bioactivity was evaluated by in vitro test in Simulated Body Fluid (SBF, 37°C, for 30days). It was shown that hybrid HAp/CNT layers are very attractive materials for modification of the surface of metallic orthopedic implants.

FT-IR study of montmorillonite-chitosan nanocomposite materials.

Bone defect is one of the most frequent problems in bone tissue reconstruction in which application of a biomaterial filling is necessary. It creates a still rising demand of biomaterials for bone surgery. Polymer-ceramic nanocomposites (e.g. based on chitosan matrix) is a group of novel materials whose properties such as strength, Young's modulus, bioactivity and controlled degradation time make them suitable materials for filling bone defects. Investigations of nanocomposite foils which consisted of biopolymer-chitosan (CS) matrix and montmorillonite (MMT) as a nano-filler was the subject of the work. The nanocomposite materials were produced by a two-step dispersion of the nanoparticles in the biopolymer matrix. The first stage involved mechanical stirring and the second one - ultrasonic agitation. Mechanical tests were performed on the nanocomposites and their Young's modulus was estimated. Significant improvement of mechanical properties of the nanocomposites in comparison with the pure polymer (CS) was observed. The nanocomposite foils (CS/MMT) were subjected to FT-IR spectroscopy investigations whose objective was to explain the reason of the change in mechanical characteristics of the nanocomposites. Transmission and ATR techniques operating in MIR range were used to study the nanocomposites. The FT-IR techniques were used to determine interactions at nanoparticle-biopolymer matrix interface. A pure unmodified CS foil was used as a reference material for FT-IR studies. It was proven that application of FT-IR techniques allows not only to identify phases, but also to explain structural changes in the systems studied.

[Carbon grafts produced from polyacrylonitrile for treatment of soft tissues]. / Implanty weglowe wytworzone z wlókien poliakrylonitrylowych w leczeniu tkanek miekkich.

The paper deals with the estimation of carbon fibres produced with the heat treatment method of polyacrylonitrile fibres for the needs of medicine. Carbon graft in the form of plaitwork were produced as active bases for the growth of soft tissues. The fibres were tested in in vivo conditions to state their influence on the living organism. The quality dependence between producing of carbon fibres, their structure, physical and chemical properties and the tissue response was presented. It was shown that the tissue response depends on the material form, structure ordering chemical state on the surface and parameters of microstructure. The influence of the structure of carbon graft surface on the way of affecting the living organism.

[Studies on development of composite biomaterials for reconstruction of the larynx]. / Badania nad opracowaniem biomaterialu kompozytowego do rekonstrukcji krtani.

The paper presents the results of studies on the development of composite material to be used in laryngology. The composite was manufactured from carbon fibres and polysulfone in the form of multiphase laminate having suitable surface properties. Mechanical properties of three different types of composite materials were analysed. Of the elaborated composites the material possessing the most advantageous mechanical properties was than analysed by means of FTIR and SEM methods. Results obtained permit determination of such composite material in laryngeal and tracheal reconstruction.

Carbon materials in the treatment of soft and hard tissue injuries.

Carbon-based implant materials are of interest because they are well accepted by the biological environment. Carbon fibrous materials developed in the Department of Special Ceramics of the University of Mining and Metallurgy in Cracow were tested in in vivo studies to determine their influence on the living body. For comparative purposes, different carbon fibers were prepared and subjected to different surface modifications. Carbon materials prepared in the form of braids were implanted in subcutaneous tissue of rabbits and into skeletal muscle of rats. Carbon fabrics were examined as scaffolds in reconstruction of bone defects. The present study examined the synthesis-structure-property relationships of fibrous carbon samples with respect to the tissue response. It was shown that the tissue response depends on the form of the material form, the degree of order of the crystallites, the surface state and microstructural parameters. Carbon fibers with higher crystallinity and a better-organized graphite structure were assimilated by the body with more difficulty and small particles coming from these materials were found in the regional lymph nodes. Low-carbonized carbon fibers (small crystallite size) underwent partial fragmentation and reacted with the biological environment by being gradually resorbed in the implantation site. The presence of acidic groups on the surface of the carbon fibers enhanced phagocytosis of the carbon material by macrophages. Depending on the surface state of carbon fibers different rates of bone wound healing were observed.

Phagocytosis of chemically modified carbon materials.

An oxidizing treatment of carbon fibres in boiling nitric acid leads to significant changes in the chemical state of their surface. As a result of the chemical treatment on a hydrophobic carbon surface, hydrophilic domains are formed and phenolic, carbonyl and carboxyl groups appear. In this work the intensity of phagocytosis of carbon fibres obtained by carbonization of polyacrylonitrile was studied both for HNO3 etched and non-etched fibres. Part of the powdered material studied was placed in plasma before it was contacted with cells. To study the material, which was first placed in plasma and then contacted with cells, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used. It was found that the powders made from the etched fibres are phagocytized more intensively. It was also found that the absorption of plasma proteins enhances the phagocytosis only for the fibres oxidized in HNO3 and has no influence in the case of powders obtained from non-etched fibres.