Novel bioactive polyester scaffolds prepared from unsaturated resins based on isosorbide and succinic acid.

In this study new biodegradable materials obtained by crosslinking poly(3-allyloxy-1,2-propylene succinate) (PSAGE) with oligo(isosorbide maleate) (OMIS) and small amount of methyl methacrylate were investigated. The porous scaffolds were obtained in the presence of a foaming system consisted of calcium carbonate/carboxylic acid mixture, creating in situ porous structure during crosslinking of liquid formulations. The maximum crosslinking temperature and setting time, the cured porous materials morphology as well as the effect of their porosity on mechanical properties and hydrolytic degradation process were evaluated. It was found that the kind of carboxylic acid used in the foaming system influenced compressive strength and compressive modulus of porous scaffolds. The MTS cytotoxicity assay was carried out for OMIS using hFOB1.19 cell line. OMIS resin was found to be non-toxic in wide range of concentrations. On the ground of scanning electron microscopy (SEM) observations and energy X-ray dispersive analysis (EDX) it was found that hydroxyapatite (HA) formation at the scaffolds surfaces within short period of soaking in phosphate buffer solution occurs. After 3h immersion a compact layer of HA was observed at the surface of the samples. The obtained results suggest potential applicability of resulted new porous crosslinked polymeric materials as temporary bone void fillers.

Novel injectable biomaterials for bone augmentation based on isosorbide dimethacrylic monomers.

Drawbacks with the commonly used PMMA-based bone cements, such as an excessive elastic modulus and potentially toxic residual monomer content, motivate the development of alternative cements. In this work an attempt to prepare an injectable biomaterial based on isosorbide-alicyclic diol derived from renewable resources was presented. Two novel dimethacrylic monomers ISDGMA - 2,5-bis(2-hydroxy-3-methacryloyloxypropoxy)-1,4:3,6-dianhydro-sorbitol and ISETDMA - dimethacrylate of ethoxylated isosorbide were synthesized and used to prepare a series of low-viscosity compositions comprising bioactive nano-sized hydroxyapatite in the form of a two-paste system. Formulations exhibited a non-Newtonian shear-thinning behavior, setting times between 2.6 min and 5.3 min at 37°C and maximum curing temperatures of 65°C. Due to the hydrophilic nature of ISDGMA, cured compositions could absorb up to 13.6% water and as a result the Young's modulus decreased from 1,429 MPa down to 470 MPa. Both, poly(ISDGMA) and poly(ISETDMA) were subjected to a MTT study on mice fibroblasts (BALB/3T3) and gave relative cell viabilities above 70% of control. A selected model bone cement was additionally investigated using human osteosarcoma cells (SaOS-2) in an MTS test, which exhibited concentration-dependent cell viability. The preliminary results, presented in this work reveal the potential of two novel dimethacrylic monomers in the preparation of an injectable biomaterial for bone augmentation, which could overcome some of the drawbacks typical for conventional acrylic bone cement.

Developing the procedure of modifying the denture soft liner by silver nanoparticles.

Colonization of denture soft lining materials by fungi and denture plaque leads to infections of mucosa. Microorganisms such as Candida albicans colonize not only the surface of the soft liners, but they also penetrate inside those materials. Therefore the use of common disinfectants, e.g., surface active cleaners, is not a perfect solution for keeping a proper hygiene of soft linings. Modifying soft lining by silver nanoparticles (AgNP) seems to be a right way to overcome those problems. The procedure of modifying two-component silicone material by silver nanoparticles (AgNP) is presented in the article. The solubility tests for both material components have been carried out in the first stage of examinations. On the basis of test results, a solvent has been selected, being a dispersion medium for AgNPs and both soft liner components. The effective method for evaporating a solvent from the composition has been developed. Material components with various AgNP concentrations (10, 20, 40, 80, 120 and 200 ppm) have been obtained. Cured samples of the composites have been examined by SEM to confirm the effectiveness of the procedure.

Investigation on synthesis and properties of isosorbide based bis-GMA analogue.

The aim of this work was to synthesize and investigate properties of a novel dimethacrylic monomer based on bioderived alicyclic diol--isosorbide. Its potential as a possible substitute of 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (BISGMA), widely used in dental restorative materials and suspected for toxicity was assessed. The novel monomer was obtained in a three-step synthesis. First, isosorbide was etherified by a Williamson nucleophilic substitution and subsequently oxidized to isosorbide diglycidyl ether (ISDGE). A triphenyl phosphine catalyzed addition of methacrylic acid to ISDGE resulted in 2,5-bis(2-hydroxy-3-methacryloyloxypropoxy)- 1,4:3,6-dianhydro-sorbitol (ISDGMA). The monomer obtained was photopolymerized using camphorquinone/2-(dimethylamino)ethyl methacrylate initiating system. Next, compositions with triethylene glycol dimethacrylate (TEGDMA) were prepared and polymerized. Double bond conversion, polymerization shrinkage and water sorption of resulting polymers were determined. Selected mechanical (flexular strength and modulus, Brinell hardness) and thermomechanical (DMA analysis) properties were also investigated. BISGMA based materials were prepared as reference for comparison of particular properties.

Antifungal activity of denture soft lining material modified by silver nanoparticles-a pilot study.

Soft liner materials in oral cavity environments are easily colonized both by fungi and dental plaque. These factors are the cause of mucosal infections. The microorganism that most frequently colonizes soft liner materials is Candida albicans. Colonization occurs on the surface of materials and within materials. A solution to this problem might involve modification of soft liner materials with silver nanoparticles (AgNPs). In this article, we present results showing the antifungal efficacy of silicone soft lining materials modified with AgNPs. The modification process was conducted by dissolving both material components (base and catalyst) in a colloidal solution of AgNPs and evaporating the solvent. Composites with various AgNP concentrations (10, 20, 40, 80, 120 and 200 ppm) were examined. The in vitro antifungal efficacy (AFE) of composite samples was 16.3% to 52.5%.

Preliminary studies on the hydrolytic degradation and biocompatibility of poly(3-allyloxy-1,2-propylene succinate).

In the present paper the synthesis and selected properties of functional aliphatic poly(3-allyloxy-1,2-propylene succinate) (PSAGE) are described. This polyester was synthesized by melt co-polymerization of succinic anhydride and allyl glycidyl ether in the presence of benzyltrimethylammonium chloride as catalyst. The chain structure of PSAGE and its end-groups was characterized by MALDI-TOF mass spectrometry. It was found that PSAGE undergoes hydrolytic degradation in phosphate buffer solution (pH 7.41) at 37 degrees C and, unexpectedly, the dependence of mass loss on immersion time turned out to be linear in the first 12 weeks, similar to hydrophobic polyanhydrides. The polysuccinate of 3600 Da was tested on rat alveolar macrophage cell line using the MTT assay to determine its cytotoxicity, as well as the NO production level, which is an indicator of cell activation. The data obtained show that PSAGE is non-toxic, and that the viability of cells ranges from 86 to 100%. The obtained results reveal the potential applicability of PSAGE as a component of biomaterials or as polymeric drug carrier.

Characterization of new biodegradable bone cement compositions based on functional polysuccinates and methacrylic anhydride.

New biodegradable poly(3-allyloxy-1,2-propylene)succinate-based materials were obtained by cross-linking poly(3-allyloxy-1,2-propylene)succinate (PSAGE) with methyl methacrylate (MMA) and methacrylic anhydride (MAAH). The aim of this study was to examine the influence of MAAH/MMA ratio and incorporation of biphasic calcium phosphate (BCP) filler on the maximum curing temperature, setting time, compressive strength and modulus of the cured materials, as well as on their hydrolytic degradation. The latter was characterized by determination of the weight loss and observation of changes in samples morphology by SEM. The maximum temperature during cross-linking was found to decrease with increasing MAAH content. The setting time was affected strongly by the concentration of double bonds and was rapidly shortened with its increase. The compressive strength and compressive modulus values increased with increasing MAAH/MMA ratio. Moreover, addition of bioactive mineral filler (BCP) improves significantly mechanical properties of these materials. On the other hand, it slows down their hydrolytic degradation.

Evaluation of oligo(ethylene glycol) dimethacrylates effects on the properties of new biodegradable bone cement compositions.

New injectable, in situ curable liquid formulations consisting of biodegradable aliphatic polyester, i.e., poly(3-allyloxy-1,2-propylene)succinate (PSAGE), methyl methacrylate (MMA), and hydrophilic oligo(ethylene glycol) dimethacrylates (OEGDMA) were investigated. The effect of MMA/OEGDMA ratio, OEGDMA molecular weight, i.e., the length of oligooxyethylene fragments, on the maximum curing temperature, setting time, compressive strength and modulus of the cured materials as well as their hydrophilicity were examined. The latter was characterized by determination of equilibrium water content and static water contact angle. The maximum temperature during crosslinking was found to decrease with increasing OEGDMA molecular weight and decreasing MMA/OEGDMA ratio. The setting time was affected strongly by the concentration of double bonds and was rapidly shortened with its increase. The compressive strength and compressive modulus values decreased with increasing OEGDMA molecular weight and decreasing MMA/OEGDMA ratio. Poly(3-allyloxy-1,2-propylene succinate).