Papers by Author: Ewa Stodolak-Zych

Abstract: The aim of the work was the deposition of polymer fibres of submicrometric and nanometric diameter. A layer of the fibres was produced from biocompatible polymer, i.e. poli (ε) caprolactane (PCL). The polymer was dissolved in a mixture of DMF:DCM solvents. In order to enhance the hydrophobic effect, silica particles (5–10 nm) were introduced into the polymer solution. PCL fibres were produced using electric field of 25 kV. Wettability of the produced layer was determined using the method of sitting drop (DSA T500). Its microstructure was observed using scanning an electron microscope (Nova NanoSEM) and an atomic force microscope (MULTIMODE 8 AFM, Bruker). It was revealed that only coatings made of the pure polymer fibres showed superhydrophobicity (PCL fibres, wetting angle of 151^o), while the nanocomposite fibres made of PCL and 3 wt.% SiO₂ formed a layer with a wetting angle of 113^o, which was more hydrophobic than a conventional polymer layer made by casting (wetting angle of PCL foil is 90^o).

Abstract: Among the many applications of polylactide (PLA) in medicine, one of the most famous is porous scaffold for bone and cartilage regeneration. A new direction in the development of biodegradable polymer scaffolds is their modification using different types of nanoadditives. One type of these nanomaterials could be carbon nanotubes (CNT), which could influence the mechanical, electrical, physicochemical and biological properties of polymer matrices. Porous nanocomposite scaffolds were prepared using different techniques, such as salt leaching and a combination of salt leaching and gas foaming techniques. The bioactivity of MWCNTs was determined through their incubation in simulated body fluid (SBF) and verified using scanning electron microscopy (SEM). The best concentration of nanoadditives in the polymer matrices was evaluated on the basis of mechanical and in vitro tests of nanocomposite films using a universal testing machine (Zwick) and osteoblast-like human cells (MG63). The morphology, porosity and mechanical properties of the porous scaffold before and after modification with MWCNTs were evaluated using SEM, hydrostatic weighing and a universal test machine.

Abstract: Aim of the work was production of nanocomposite polymer fibres containing ceramic particles using the electrospinning method and characterisation of morphology and bioactivity of the produced materials. The first stage of investigations consisted in preparation of a series of poly-L-lactide (PLA) solutions in various solvents mixtures in order to reach viscosity which would allow formation of fibres by the electrospinning method. Ceramic nanoparticles such as tricalcium phosphate (TCP) and silica (SiO₂) were used as nanofillers of the polymer matrix. Their particle size distribution in the solvent solution as well as in the polymer suspension was determined by dynamic light scattering method (DLS). Morphology of the nanoparticles was observed using transmission electron microscopy (TEM). Distribution of the nanofillers in the nanocomposite fibres as well as diameter and morphology of the fibres was assessed using scanning electron microscopy with energy dispersive spectroscopy method (SEM/EDS). Effect of the nanofillers addition and the shaping method on the structure of the PLA matrix was investigated on the basis of the thermal analysis methods (TG/DSC) on the nanocomposite foils prepared by casting. It was revealed that the nanocomposite fibres showed apatite nucleation in in vitro conditions i.e. after incubation in SBF (37°C/ 3 days).

Abstract: In this work, experiments to produce a series of nanocomposites based on natural chitosan and nano-clay (MMT) were conducted. Commercially available montmorillonite (MMT) was used as a nanofiller. CS-MMT nanocomposites were prepared using the casting method. Thin nanocomposite foils were neutralized in NaOH solution, then the nanocomposite foils were soaked in simulated body fluid (SBF). Kinetics of crystallization of the apatite structure was observed using PIXE, FTIR-ATR and SEM/EDS techniques. It was shown that high concentrations of calcium and phosphate ions were located inside the nanocomposite structure. Bioactivity phenomena was initiated first in the nanocomposite foils (CS/MMT) and then in pure chitosan foils. These results suggest that the nano-clay particles (MMT) distributed in the biopolymer matrix acted as nucleaction centers of apatite. An apatite layer on pure chitosan crystallized much more slowly than in the case of nanocomposite materials. The CS-MMT nanocomposites therefore seem to be promising materials for bone repair implants because of their inherent bioactivity.