Skin substitutes are heterogeneous group of scaffolds (natural or synthetic) and cells. We hypothesize that nanofibers with layer composition made of polylactide (PLA) and sodium hyaluronate (HA) obtained using electrospinning method are a good matrix for cell adhesion and proliferation. Methods: Optimal conditions of electrospinning of PLA and HA nanofibers to create layered compositions (PLA membrane covered with HA nonwovens) were determined by modifying parameters such as the appropriate amount of solvents, polymer concentration, mixing temperature and electrospinning process conditions. By changing the parameters, it was possible to control the diameter and properties of both polymer fibers. The spinning solution were characterized by surface tension and rheology. A scanning electron microscope (SEM) was used to determine the morphology and fiber diameters: PLA and HA. Structure of the PLA/HA nonwoven was analyzed using spectroscopy (FTIR/ATR). Biocompatibility of the nonwoven with fibroblasts (ECM producers) was assessed in the in vitro conditions. Results: The results showed that stable conditions for the formation of submicron PLA fibers were obtained using a 13% wt. solution of the polymer, dissolved in a 3:1 mixture of DCM:DMF at 45 °C. The hyaluronic fibers were prepared from a 12% wt. solution of the polymer dissolved in a 2:1 mixture of ammonia water and ethyl alcohol. All materials were biocompatible but to a different degree. Conclusions: The proposed laminate scaffold was characterized by a hydrophobic-hydrophilic domain surface with a maintained fiber size of both layers. The material positively underwent biocompatibility testing in contact with fibroblasts.
The aim of this work was to examine composite membranes obtained by means of phase inversion from a synthetic stable polymer – polyvinylidene difluoride (PVDF). The piezoelectric polymer was modified with 0.5-1wt% addition of commercial carbon fillers: graphite oxide (GO, 1wt%), multiwalled carbon nanotubes (CNT, 1wt%) and functionalized nanotubes (CNT-COOH, 0.5wt%). The membranes were obtained by solidification of nanocomposite solutions in coagulation bath (CH3OH). The obtained series of materials differed in surface porosity (P), electric conductivity (σ) and surface free energy (SFE). It was proved that presence of carbon nanoadditive influenced microstructure of the membranes: the mean size of pores in the membrane rose in the following order: GO→CNT→CNT-COOH. The very same system depicted the influence of the filler on the membrane structure: the increase in membrane crystallinity (λ) and the β phase share (FT Raman). From all the examined nanocomposite systems, the PVDF modified with 0.5wt% CNT-COOH displayed the most advantageous electric properties. These nanocomposite membrane (PVDF/CNT-COOH) could be used as a low-voltage electrodes in biomedical application. Yet, taking into account the other physicochemical, mechanical and structural properties, the membranes modified with 1wt% CNT and 1wt% GO were also interesting.
Celem pracy była ocena możliwości wykorzystania montmorylonitu (MMT), jako potencjalnego nośnika leków o ujemnym potencjale elektrokinetycznym, tj. indomatacyny i naproksenu, mających działanie przeciwzapalne i przeciwbólowe. Nośniki leków na bazie montmorylonitu otrzymano poprzez interkalację leków w materiałach w formie proszków w procesie 24-godzinnego mieszania zawiesiny surowca w roztworze wodnym wraz z rozpuszczonym lekiem w temperaturach 20 °C, 50 °C i 80 °C. Uzyskane materiały badano pod kątem ilości i sposobu wprowadzenia leku w strukturę montmorylonitu. Zmiany potencjału elektrokinetycznego otrzymanych koniugatów (materiał hybrydowy MMT-lek) w stosunku do wyjściowego montmorylonitu określono, wykonując pomiar potencjału zeta. Ocenę możliwości wprowadzenia leków w przestrzenie międzypakietowe MMT przeprowadzono z wykorzystaniem dyfraktometrii rentgenowskiej (XRD) i spektroskopii w podczerwieni (FTIR). Obserwacji zmian morfologii proszków po interkalacji lekiem dokonano przy wykorzystaniu skaningowej mikroskopii elektronowej (SEM). Wyniki badań potwierdziły możliwość wbudowania leków w strukturę minerału, jednakże ujemny potencjał elektrokinetyczny leków uniemożliwiał całkowitą ich interkalację pomiędzy warstwy montmorylonitu. Na proces interkalacji miała wpływ temperatura procesu. Najkorzystniejsza z punktu widzenia procesu interkalacji okazała się temperatura 50 °C.
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The aim of the study was to investigate the use of montmorillonite (MMT) as a potential drug carrier. Two medicines with a negative electrokinetic potential were selected for intercalation of montmorillonite, namely indomethacin and naproxen, having anti-inflammatory and analgesic properties. Montmorillonite-based drug carriers were prepared by a 24 hours stirring of suspension with an aqueous solution of both dissolved drugs at 20 °C, 50 °C and 80 °C. The obtained materials were tested for the amount and ways of incorporation of the drug in the montmorillonite structure. Changes in electrokinetic potential of the obtained carriers (MMT-drug hybrids) as compared to the starting montmorillonite were determined by measuring the zeta potential. The presence of the drug introduced into the interlayer spaces of MMT was examined using the following measurement methods: X-ray diffraction (XRD), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results confirmed the possibility of drug incorporation into the structure of the mineral. The efficiency of intercalation was found to be depended on the temperature of process, and the most preferred one from that viewpoint was the processing at a temperature of 50 °C. However, the negative zeta potential of the drug prevented the complete intercalation of the drug between the layers of montmorillonite.
Purpose: The aim of the study was to evaluate the influence of an implant made of a terpolymer (PTFE-PVDF-PP) on the condition of rabbit eyes during a one year observation period. Methods: The implant in the shape of an equilateral triangle (3 mm side length) was manufactured from a thin hydrophobic porous membrane. There were evaluated 40 eyes of 20 rabbits. The animals had non-penetrating very deep sclerectomy (NPVDS) performed, with insertion of an implant in the form of a triangular thin membrane. The control group consisted of 20 eyes where the animals had NPVDS performed without implant insertion. The evaluations included the study of the anterior part of the eye together with photographic documentation. Histopathological examination of the eyes 52 weeks after NPVDS procedure has been made. The process of wound healing was comparable in both groups. Results: The evaluation of the rabbits did not reveal any acute process of intraocular inflammation. After 12 month period of observation, no statistically significant differences in the process of wound healing or status of eyes were found between the groups. An analysis of fibrous connective tissue attachment to the implant showed that its layer was not thick and did not differ significantly from the control. The procedure of very deep sclerectomy and insertion of a polymer implant were well tolerated by the rabbit eyes. Conclusions: The in vivo results indicate that the hydrophobic implant in the form of a membrane can serve as a sclera implant after further study.
The work focuses on polymeric cartilage/bone pins (pegs) that were manufactured and tested to assess their application in meniscus injuries. The bone pins measuring 1,2 and 4 mm in diameter were produced from certified resorbable PLDLA by means of hot pressing (at 126oC). In order to establish the material characteristics, tests of mechanical properties, structural testing and stability tests were performed in vitro (an immersion medium: water/PBS buffer). It was established that after three months of incubation the initial implant’s bending strength (120 MPa) decreased by 35%, whereas its tensile strength (52 Pa) weakened by 60%. The degree of degradation did not affect the pH of the immersion fluid. The observed physical changes of the implant, such as: the mass decrease, the change of shape, the increase of crystallinity (DSC/TG), the number of polymer terminal groups (-OH, -COOH), proved the advanced degradation process of PLDLA pins. Implants of particular behaviour were inoculated into the tibia of a New Zealand rabbit. In vivo tests were conducted to confirm the changes observed in vitro. Monitoring of the degradation process was performed after three months following the implantation by means of control X-ray and computed microtomography (μCT).
The nanocomposite material based on chitosan was obtained and characterized. Commercially produced biopolymer at 85% deacetylization degree was used. The biopolymer matrix was modified with carbon nanofillers such as graphite oxide (GO), carbon nanotubes (CNTs) and nanontubes with the surface affected by carboxyl groups (CNT-COOH). The obtained nanocomposites were formed by means of two methods: casting (to manufacture nanocomposite foils) and liofilization (to manufacture porous nanocomposite materials). Their electrical properties and microstructure were examined. The tests proved that adding the carbon nano-filler results in high resistivity (graphite foils, carbon nanotubes) and also the average size of pores in liofilized materials. Additionally, the electric potential of the materials may be improved by surface processing (EPD- electrophoretic deposition). The described materials are an alternative to polymer nerve implants e.g. tubes or hydrogels which are already present on the market and applied to regenerate nerves.
Nanoclay-filled polylactide (PLA 3051D) composite materials were tested in this study and their capacity for degradation was investigated. Activated and lyophilized smectite clay was used. The filler, its morphology, and grain size distribution were characterized by the use of transmission electron microscopy, scanning electron microscopy, and the dynamic light scattering technique. Samples of pure polylactide and polylactide filled with 3% wt., 5% wt., and 10% wt. of nanoclay in subsequent series were obtained by injection molding. The optimum amount of the filler in the nanocomposites was evalu-ated based on an assessment of mechanical properties as well as capacity to degrade. The 3% wt. mass fraction of nanofiller in the polylactide matrix was found to be the most effective in enhancement of both tensile strength (RM) and Young’s Modulus (E). It was also reported that polylactide nanocomposites filled with 3% wt. of smectite clay were characterized by the highest decrease in molecular mass of the matrix polymer after degradation tests (6 weeks incubation in water at 80°C). The observed decrease in degradation time and the overall changes distinguished in the nanocomposite structure suggest the poten-tial for application of the material in the packaging industry.
The aim of the study was evaluation of possibility of poly-ε-caprolacton (PCL) application as potential material for production of medical devices, as catheters for obtaining and transporting of embryos as well as dishes for embryos culture in vitro and covers for cryoconservation. The possible application of this biomaterial needs verification of its biological properties on embryos culture. The foil discs made of policaprolacton, thickness 0.5 mm, diameter 3.5 mm, were prepared in two forms: the baseline one (nPCL) and thermally modified by freezing with liquid nitrogen (mPCL). The verification of PCL bioconcordance was performed by evaluation of 102 pig embryos. To evaluate poly-ε-caprolacton bioconcordance we performed 5-day long culture of embryos on the evaluated material, not frozen (nPCL) and frozen in liquid nitrogen (mPCL) and additionally culture after short contact with poly-ε-caprolacton, lasting 15 minutes (nPCL-15). In all evaluated study groups the development of embryos was suppressed shortly after transfer to the culture with PCL. In the control group. 74%-78% of embryos reached blastocyst stage. Polycaprolacton cannot be used as the material for catheter production used in biotechnology of animal reproduction and other materials used for in vitro culture and cryoconservation.
The paper presents research on degree of bioactivity of nanometric ceramic particles used as a nanofiller in nanocomposite materials based on polymers. The nanoperticles used in our examination were: different bioceramics powders such as: hydroxyapatite (HAp), β-phosphate (V) calcium (βTCP), silica (SiO2) and bioglass (BG). Based on ζ-potential measurements dynamics of processes occurring on the surface of nanoparticles in stimulated body fluid (SBF) was determined and it confirmed possibility of apatite formation. This study showed predominance of bioglass over other bioceramic materials, Bioglass nanoparticles were the most bioactive ones. In the end of the experiment the bioacermic particles were used as a nanofiller of poli-L/DL-lactide (PLDLA) matrix composites. The composite materials were prepared by casting from solution. Bioactivity tests were performed in simulated body fluid (artificial plasma of various ions concentration, and SBF 2SBF). Based on surface microstructure observed in the SEM (EDS) analysis were confirmed the degree of bioactivity of various materials depending on the type nanofiller.
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