Surface-modified poly(l-lactide-co-glycolide) scaffolds for the treatment of osteochondral critical size defects : in vivo studies on rabbits

Poly(l-lactide-co-glycolide) (PLGA) porous scaffolds were modified with collagen type I (PLGA/coll) or hydroxyapatite (PLGA/HAp) and implanted in rabbits osteochondral defects to check their biocompatibility and bone tissue regeneration potential. The scaffolds were fabricated using solvent casting/particulate leaching method. Their total porosity was 85% and the pore size was in the range of 250–320 µm. The physico-chemical properties of the scaffolds were evaluated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), sessile drop, and compression tests. Three types of the scaffolds (unmodified PLGA, PLGA/coll, and PLGA/HAp) were implanted into the defects created in New Zealand rabbit femoral trochlears; empty defect acted as control. Samples were extracted after 1, 4, 12, and 26 weeks from the implantation, evaluated using micro-computed tomography (µCT), and stained by Masson–Goldner and hematoxylin-eosin. The results showed that the proposed method is suitable for fabrication of highly porous PLGA scaffolds. Effective deposition of both coll and HAp was confirmed on all surfaces of the pores through the entire scaffold volume. In the in vivo model, PLGA and PLGA/HAp scaffolds enhanced tissue ingrowth as shown by histological and morphometric analyses. Bone formation was the highest for PLGA/HAp scaffolds as evidenced by µCT. Neo-tissue formation in the defect site was well correlated with degradation kinetics of the scaffold material. Interestingly, around PLGA/coll extensive inflammation and inhibited tissue healing were detected, presumably due to immunological response of the host towards collagen of bovine origin. To summarize, PLGA scaffolds modified with HAp are the most promising materials for bone tissue regeneration

Physico-chemical and biological evaluation of doxycycline loaded into hybrid oxide-polymer layer on TiMo alloy

Oxide-polymer coatings were formed on the surface of the vanadium-free Ti-15Mo titanium alloy. The Ti alloy surface was modified by the plasma electrolytic oxidation process, and then, the polymer layer of a poly (D, Llactide- co-glycolide) with doxycycline was formed. The polymer evenly covered the porous oxide layer and filled some of the pores. However, the microstructure of the polymer surface was completely different from that of the PEO layer. The surface morphology, roughness and microstructure of the polymer layer were examined by scanning electron microscopy (SEM) and a confocal microscope. The results confirmed the effectiveness of polymer and doxycycline deposition in their stable chemical forms. The drug analysis was performed by highperformance liquid chromatography. The $^{1}$H NMR technique was used to monitor the course of hydrolytic degradation of PLGA. It was shown that the PLGA layer is hydrolysed within a few weeks, and the polyglycolidyl part of the copolymer is hydrolysed to glycolic acid as first and much faster than the polylactide one to lactic acid. This paper presents influence of different microstructures on the biological properties of modified titanium alloys. Cytocompatibility and bacterial adhesion tests were evaluated using osteoblast-like MG-63 cells and using the reference S. aureus and S. epidermidis strains. The results showed that the optimum concentration of doxycycline was found to inhibit the growth of the bacteria and that the layer is still cytocompatible

Antibacterial and cytocompatible coatings based on poly(adipic anhydride) for a Ti alloy surface

This paper describes a formation of hybrid coatings on a Ti–2Ta–3Zr–36Nb surface. This is accomplished by plasma electrolytic oxidation and a dip-coating technique with poly(adipic anhydride) ((C$_{6}$H$_{8}$O$_{3}$)n) that is loaded with drugs: amoxicillin (C$_{16}$H$_{19}$N$_{3}$O$_{5}$S), cefazolin (C$_{14}$H$_{14}$N$_{8}$O$_{4}$S$_{3}$) or vancomycin (C$_{6}6$H$_{75}$Cl$_{2}$N$_{9}$O$_{24}$ · xHCl). The characteristic microstructure of the polymer was evaluated using scanning electron microscopy and confocal microscopy. Depending on the surface treatment, the surface roughness varied (between 1.53 μm and 2.06 μm), and the wettability was change with the over of time. X-ray photoelectron spectroscopy analysis showed that the oxide layer did not affect the polymer layer or loaded drugs. However, the drugs lose their stability in a phosphate-buffered saline solution after 6.5 h of exposure, and its decrease was greater than 7% (HPLC analysis). The stability, drug release and concentration of the drug loaded into the material were precisely analyzed by high-performance liquid chromatography. The results correlated with the degradation of the polymer in which the addition of drugs caused the percent of degraded polymer to be between 35.5% and 49.4% after 1 h of material immersion, depending on the mass of the loaded drug and various biological responses that were obtained. However, all of the coatings were cytocompatible with MG-63 osteoblast-like cells. The drug concentrations released from the coatings were sufficient to inhibit adhesion of reference and clinical bacterial strains (S. aureus). The coatings with amoxicillin showed the best results in the bacterial inhibition zone, whereas coatings with cefazolin inhibited adhesion of the above bacteria on the surface

Resorbowalne membrany do sterowanej regeneracji tkanek rozprawa doktorska /

Tyt. z ekranu tytułowego.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2013.Zawiera bibliogr.Dostępna także w wersji drukowanej.Tryb dostępu: Internet.Choroby przyzębia, niechirurgiczne, chirurgiczne metody leczenia, metody leczenia tkanek przyzębia opierające się na reperacji, na regeneracji, membrany wykorzystywane do leczenia chorób przyzębia metodą sterowanej regeneracji tkanek, GTR, wymagania stawiane materiałom membranowym do sterowanej regeneracji tkanek, rodzaje membran stosowanych w technice GTR, membrany nieresorbowane, resorbowalne, materiały membranowe pochodzenia naturalnego, syntetycznego, membrany gradientowe, charakterystyka materiału matrycowego poli(L-laktydu-co-glikolidu), PLGA, charakterystyka porogenu poli(glikolidu etylenowego), PEG, otrzymywanie, charakterystyka membran, grubość, udział objętościowy porów, mikrostruktura, topografia, zwilżalność, właściwości chemiczne powierzchni, wytrzymałość mechaniczna, szybkość odparowania rozpuszczalnika, badania degradacji, właściwości biologiczne, badania na komórkach osteoblastopodobnych MG-63, żywotność komórek, poziom tlenku azotu, morfologia komórek, badania z wykorzystaniem ludzkich mezenchymalnych komórek macierzystych, ludzkich fibroblastów, ocena proliferacji, różnicowania, mineralizacji komórek, morfologia komórek, badania w kokulturach komórkowych, hodowla komórek po obu stronach membrany, mechanizm separacji faz, tworzenia membran PLGA w zależności od stężenia PEG, morfologia membran, mikrostruktura, właściwości mechaniczne, mechanizm separacji faz, tworzenia membran PLGA w zależności od masy cząsteczkowej PEG, mikrostruktura, grubość membran, procent wypłukania PEG, wpływ odparowania rozpuszczalnika na mikrostrukturę membran, badania FTIR-ATR, degradacji membran, ocena makroskopowa, zmiany masy, pH, kąt zwilżania, wytrzymałość, SEM, AFM, charakterystyka biologiczna membran, badania membran PLGA w kontakcie z komórkami osteoblastopodobnymi MG-63, żywotności komórek, poziom tlenku azotu, morfologia komórek, badania membran w kontakcie z ludzkimi fibroblastami, ludzkimi mezenchymalnymi komórkami macierzystymi, proliferacja komórek, różnicowanie, mineralizacja komórek, morfologia komórek, badania w kokulturach komórkowych, ludzkie fibroblasty, mezenchymalne komórki macierzyste, model symulujący warunki panujące w organizmie żywy

Resorbowalne membrany do sterowanej regeneracji tkanek

Tyt. z ekranu tytułowego.Promotor: Elżbieta Pamuła.Niepublikowana praca doktorska.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2013.Zawiera bibliogr.Dostępna także w wersji drukowanej.Tryb dostępu: Internet.Choroby przyzębia, niechirurgiczne, chirurgiczne metody leczenia, metody leczenia tkanek przyzębia opierające się na reperacji, na regeneracji, membrany wykorzystywane do leczenia chorób przyzębia metodą sterowanej regeneracji tkanek, GTR, wymagania stawiane materiałom membranowym do sterowanej regeneracji tkanek, rodzaje membran stosowanych w technice GTR, membrany nieresorbowane, resorbowalne, materiały membranowe pochodzenia naturalnego, syntetycznego, membrany gradientowe, charakterystyka materiału matrycowego poli(L-laktydu-co-glikolidu), PLGA, charakterystyka porogenu poli(glikolidu etylenowego), PEG, otrzymywanie, charakterystyka membran, grubość, udział objętościowy porów, mikrostruktura, topografia, zwilżalność, właściwości chemiczne powierzchni, wytrzymałość mechaniczna, szybkość odparowania rozpuszczalnika, badania degradacji, właściwości biologiczne, badania na komórkach osteoblastopodobnych MG-63, żywotność komórek, poziom tlenku azotu, morfologia komórek, badania z wykorzystaniem ludzkich mezenchymalnych komórek macierzystych, ludzkich fibroblastów, ocena proliferacji, różnicowania, mineralizacji komórek, morfologia komórek, badania w kokulturach komórkowych, hodowla komórek po obu stronach membrany, mechanizm separacji faz, tworzenia membran PLGA w zależności od stężenia PEG, morfologia membran, mikrostruktura, właściwości mechaniczne, mechanizm separacji faz, tworzenia membran PLGA w zależności od masy cząsteczkowej PEG, mikrostruktura, grubość membran, procent wypłukania PEG, wpływ odparowania rozpuszczalnika na mikrostrukturę membran, badania FTIR-ATR, degradacji membran, ocena makroskopowa, zmiany masy, pH, kąt zwilżania, wytrzymałość, SEM, AFM, charakterystyka biologiczna membran, badania membran PLGA w kontakcie z komórkami osteoblastopodobnymi MG-63, żywotności komórek, poziom tlenku azotu, morfologia komórek, badania membran w kontakcie z ludzkimi fibroblastami, ludzkimi mezenchymalnymi komórkami macierzystymi, proliferacja komórek, różnicowanie, mineralizacja komórek, morfologia komórek, badania w kokulturach komórkowych, ludzkie fibroblasty, mezenchymalne komórki macierzyste, model symulujący warunki panujące w organizmie żywy

Polylactide/Hydroxyapatite Nonwovens Incorporated into Chitosan/Graphene Materials Hydrogels to Form Novel Hierarchical Scaffolds

In this study, hierarchical, cylindrical scaffolds based on polylactide (PLA) microfibers incorporated into chitosan (CS) hydrogel were prepared for potential use in bone tissue engineering. PLA nonwovens modified with hydroxyapatite particles (HAp) were obtained using the electrospinning method. Then, three-dimensional scaffolds were created by rolling up the nonwovens and immersing them in CS-based solutions with graphene oxide (GO) or reduced graphene oxide (rGO) dispersed in the polymer matrix. Hydrogels were cross-linked using a novel freezing-thawing-gelling method. A broad spectrum of research methods was applied in order to thoroughly characterize both the nanofillers and the composite systems: scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffractometry, attenuated total reflection Fourier transform infrared spectroscopy, rheological and mechanical testing, as well as the assessment of chemical stability, bioactivity and cytocompatibility

Synthesis and Characterization of Chitosan/Reduced Graphene Oxide Hybrid Composites

Graphene family materials (GFM) are currently considered to be one of the most interesting nanomaterials with a wide range of application. They can also be used as modifiers of polymer matrices to develop composite materials with favorable properties. In this study, hybrid nanocomposites based on chitosan (CS) and reduced graphene oxide (rGO) were fabricated for potential use in bone tissue engineering. CS/rGO hydrogels were prepared by simultaneous reduction and composite formation in acetic acid or lactic acid and crosslinked with a natural agent—tannic acid (TAc). A broad spectrum of research methods was applied in order to thoroughly characterize both the components and the composite systems, i.e., X-ray Photoelectron Spectroscopy, X-ray Diffractometry, Attenuated Total Reflection Fourier-Transform Infrared Spectroscopy, Scanning Electron Microscopy, ninhydrin assay, mechanical testing, in vitro degradation and bioactivity study, wettability, and, finally, cytocompatibility. The composites formed through the self-assembly of CS chains and exfoliated rGO sheets. Obtained results allowed also to conclude that the type of solvent used impacts the polymer structure and its ability to interact with rGO sheets and the mechanical properties of the composites. Both rGO and TAc acted as crosslinkers of the polymer chains. This study shows that the developed materials demonstrate the potential for use in bone tissue engineering. The next step should be their detailed biological examinations

Chitosan and Sodium Hyaluronate Hydrogels Supplemented with Bioglass for Bone Tissue Engineering

The aim of the study was to produce biocomposites based on chitosan and sodium hyaluronate hydrogels supplemented with bioglasses obtained under different conditions (temperature, time) and to perform an in vitro evaluation of their cytocompatibility using both indirect and direct methods. Furthermore, the release of ions from the composites and the microstructure of the biocomposites before and after incubation in simulated body fluid were assessed. Tests on extracts from bioglasses and hydrogel biocomposites were performed on A549 epithelial cells, while MG63 osteoblast-like cells were tested in direct contact with the developed biomaterials. The immune response induced by the biomaterials was also evaluated. The experiments were carried out on both unstimulated and lipopolysaccharide (LPS) endotoxin-stimulated human peripheral blood cells in the presence of extracts of the biocomposites and their components. Extracts of the materials produced do not exhibit toxic effects on A549 cells, and do not increase the production of proinflammatory cytokines tumour necrosis factor alpha (TNF-α) and interleukin (IL-6) by blood cells in vitro. In direct contact with MG63 osteoblast-like cells, biocomposites containing the reference bioglass and those containing SrO are more cytocompatible than biocomposites with ZnO-doped bioglass. Using two testing approaches, the effects both of the potentially toxic agents released and of the surface of the tested materials on the cell condition were assessed. The results pave the way for the development of highly porous hydrogel–bioglass composite scaffolds for bone tissue engineering