Immobilization of collagen - an effective method of improving cell adhesion on polymeric materials

Surface properties of poly(L-lactide-co-glycolide) (PLG), and two reference materials: hydrophobic polystyrene (PS) and hydrophilic tissue culture polystyrene (TCPS) were modified by collagen adsorption. The morphology of the obtained collagen film was observed by using atomic force microscopy. On PLG and TCPS collagen layer was uniform, while on PS collagen formed isolated patches. The differences in supramolecular organization of collagen were due to differences in surface wettability. The behaviour of L929 fibroblasts incubated on all raw and collagen-modified surfaces was then evaluated. The best adhesion and spreading of cells, as expected, were observed on TCPS. Collagen adsorbed on PLG and PS considerably improved adhesion and spreading of fibroblasts

Fibroblast biological activity on poly(l-lactide) and poly(l-lactide-co-trimethylene carbonate)

Poly-L-lactide (PLLA) is acknowledged biocompatible polyester. However, it possesses high crystallinity/brittleness/stiffness and requires long time for complete degradation. In the current study we present data on PLTMC, a copolymer of L-lactide and trimethylene carbonate (TMC). Poly(trimethylene carbonate) (PTMC) is characterised by good mechanical properties and rapid degradation rate and for this it might possess new desired features for medical applications. During the experiments, adhesion and activity of fibroblasts cultured on PLLA and PLTMC were studied and compared during two time points of 3 and 5 days. On day 3, the number of adherent fibroblasts was compromised when fibroblasts were cultured in the presence of PLTMC but the proper adherence was recovered by day 5. The same pat-tern was observed when we evaluated some activity parameters of fibroblasts. In particular, the release of proteins and nitric oxide was studied as the increased levels of the mediators might indicate unwanted inflammatory-like condition. Overall, the results suggest that the synthesized PLTMC initially shows unwanted effects on fibroblasts but with the time these effects are abolished. Therefore PLTMC seems to represent a new material that is non-cytotoxic and compatible with the living cells

Biocomatibility study of BOC polymer mesh enriched with HAp and TCP covered by PCL fibres

The study was conducted in order to determine the biocomatibility of polimer mesh based on BOC and enriched with HAp or TCP coverd by PCL sub-micrometric fibres. Human osteoblast cell line NHOst was cultured in standard conditions on disk-shaped polymer samples. Interactions between materials and cells were examined through microscopic observation of cells' adhesion and morphology, and tests of viability/proliferation and cytotoxicity. The study proved the biocompatibility of all examined materials, though the surface of TCP enriched polymer didn't promote the adhesion of cells

Chemical modification of poly ε-caprolactone with wollastonite and its influence on biological properties of osteoblast like-cells MG-63

PCL (poly-ε-caprolactone) is a biocompatible and biodegradable polymer of aliphatic polyester group. However, PCL does not effectively bind to the bone in contrast to bioactive inorganic compounds such as wollastonite. For this wollastonite (WS) is regarded as a potential bioactive material for bone tissue engeenering although its main drawback is brittlennes. Therefore we synthesized polymer nanocomposite materials composed of poly-ε-caprolactone and wollastonite (PCL/wollastonite) containing either 0.5% or 5% of the latter modifying filler. And we aimed to verify biological properties of the nanocomposite PCL/WS materials, in comparison to the pure PCL, on cultures of osteoblast-like cells MG-63. The study revealed that the adherence of the osteoblast-like cells to the tested materials was enhanced by the PCL modification (PCL/5WS > PCL/0.5WS > PCL) while cell viability/proliferation was not altered. Furthermore, the activity of alkaline phosphatase indicative of osteoblast differentiation (maturation) was enhanced when the cells were cultured with either PCL/5WS or PCL/0.5WS. Overall, our results indicate that PCL-modified wollastonite improves biological properties of the basic biomaterial suggesting its potential usefulness/application for the bone tissue regeneration

Porous titanium scaffolds with modified surface: in vitro cell biology assessment

Interaction of host cells with a biomaterial surface is important for biocompatibility and thus is essential for biomedical applications. Therefore investigations are undertaken to scrutinize for an appropriate surface coating with physical and chemical properties minimizing undesirable activation of immunological response. For this the current study was aimed at examining the effects of different surface modifications of titanium by its coating with ceramic materials - hydroxyapatite, bioglass and CaO-SiO2on osteoblast morphology and secretory activity. Titanium is known for its excellent mechanical properties but its surface has low bioactivity. We report that CaO-SiO2coating decreased a number of attached osteoblasts and altered their morphology. Moreover, the ceramic coatings temporarily upregulated release of pro-inflammatory cytokines IL-6 (all of them) and TNF-α (CaO-SiO2). However, overall the levels of the cytokines were low. In contrast, levels of neutrophil-attracting chemokine IL-8 were the highest. IL-8 was produced mostly by cells incubated with hydroxyapatite titanium coating in contrary to those incubated with either bioglass or CaO-SiO2titanium modifications. In conclusion, the titanium coated with ceramics such as hydroxyapatite or bioglass had the best effect on cell adhesion; however, hydroxyapatite might potentially stimulate destructive neutrophils while CaO-SiO2-coating has a negative effect on cell adhesion

The effect of titanium alloy modified with a-C:N:H and a-SiCxNY(H) coatings on adhesion and immune response of human osteoblast-like MG-63 cells

The study was conducted in order to determine the effects of modified titanium alloy (Ti-6Al-4V) surfaces on the biological response of a human osteoblast-like cell line. MG-63 cells were cultured on disk-shaped Ti-alloys: unmodified, and covered with a-C:N:H or a-SiCxNy(H) layers. Interactions between materials and cells were examined through determination of cells adhesion and secretion of cytokines involved in the development of immune response

Biocompatibility of hybrid fibrous materials basing on poly-L/DL-lactide

Hybrid biomaterials due to their unique structure may become an alternative for many popular composite and nanocomposite materials. Multilevel modification of their matrix manifesting itself in the presence of particles of different sizes i.e., micrometric, submicrometric and nanometric together with the variety of shapes of a modyfing phase (nanometric fibres, submicron particles, coated nanoparticles) and its different chemical character make the hybrid materials similar to natural tissue. Bone tissue structure is particulary close to this model in which collagen fibres and hydroxyapatite particles and nanoparticles have not only different form but first of all they play different role in the tissue which depends on their chemical nature. In the biomedical engineering syntetic hybride biomaterials are usually produced using resorbable and degradable polymer matrices and inorganic filers (ceramic bioactive particles; HAp, TCP, SiO2) or organic filers (collagen, polysaccharides e.g. alginate fibres). The main function of the modyfing phase is inprovement of the polymer matrix leading to bioactive, stronger material showing high biofunctionality. Production of hybrid materials is based mainly on experimental works, which is related to the presence in their matrix few phases with different properties which may interact. Hybrid materials do not follow the rule of mixtures thus it is difficult to predict behaviour of a material in which co-exis different chemical and phisical phases. In the work hybrid composite foils were produced in which modyfing phase consisted in; nanocomposite calcium alginate fibres modyfied with ceramic nanoparticles; HAp (CAH fibres), TCP (CAT fibres), SiO2 (CAS fibres) and MMT (CAM fibres). Short fibres were subjected to additional size reduction in vibration ball mill resultiong in submicron and nanometric phases. Size of the particels after grinding was determined by screening analysis and DLS method (for particels smaller than 500 nm). It was observed than the population of short fibres consist in three fractions i.e.; micrometric (~2μm, 50 wt.%), submicrometric (500–800 nm, 40 wt.%) and nanometric ( below 500 nm, 10 wt.%). The fibres and products of their grinding were homogenised in P(L/ DL)LA polymer solution (poly-L/DL-lactide, Purarorb 80, Purac Germany). A hybride material in the form of thin foils containing 2 wt.% of a modyfing phase were subjected to durability tests consisting in incubation in distilled water (30 days/37C). Monitoring of the medium pH and conductivity did not show changes related to harmful products of their decomposition. Osteoblast-like cells from MG-63 line contacted with the surface of the materials showed high viability (MMT test) comparable with the reference material (TCPS). High degree of adherence of the cells to the materal surface (CV test) testifies of potential abilities of the material stimulating proliferation of bone tissue cells. The highes rate of dynamic growth (increase of the cells number after 7 days of incubation) was observed for the material which was modified with CAS fibres and products of their grinding. The performed investigations have a preliminary character. Their results testify for potential osteoconductive or osteoinductive abilities of hybride materials basing on P(L/DL)LA and alginate nanocomposite fibres