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Poly(phenylacetylene) with rationally designed urea groups was demonstrated to be a superior anion receptor possessing both a colorimetric response ability and a positive homotropic allosteric binding mode. The target polymer, poly(phenylacetylene) with [bis(trifluoromethyl)phenyl]urea pendants (poly-1), was synthesized by the stereoselective polymerization with Rh(nbd)BPh 4 (nbd = norbornadiene) in high yield. The anion sensing ability of poly-1 was evaluated using the tetra-n-butylammonium (TBA) salts of a series of anions in THF. Upon the addition of anions such as-, and HSO 4 -, the yellow color of the THF solution of poly-1 immediately turned to a different color depending on the types of anions, indicating the anion recognition capability of poly-1. The 1 H NMR titrations of poly-1 by using increasing amounts of CH 3 CO 2 revealed that the colorimetric response of poly-1 was considered to be the direct consequence of the hydrogen-bonding complex formation between the urea functionality and the anions. Interestingly, during the course of the determination of the anion-binding affinity, we encountered highly cooperative binding ability of poly-1. The Hill plot analysis provided an exceptional positive cooperativity, e.g., 8.4 of Hill coefficient in the complexation between poly-1 and C 6 H 5 CO 2 -. This result clearly indicated that this binding mode was based on a positive homotropic allosterism, in which the partially formed urea/anion complex units in the polymer chain should produce a change in the whole main chain conformation, facilitating further anion binding. Additionally, by comparing the anion binding of poly-1 with that of previously prepared urea-functionalized poly(phenylacetylene) (poly-2), an enhanced anion binding ability based on two electron-withdrawing -CF 3 groups was found to be essential to realize such cooperativity.

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In this work, composite membranes were investigated as future components of a layered implant for the reconstruction of nasal septum. Incorporation of zinc ions into nasal implants could potentially provide antibacterial properties to decrease or eliminate bacterial infections and subsequent surgical complications. Two types of membranes were prepared using an electrospinning method: PCL with bioglass and PCL with bioglass doped with Zn. The aim of this work was to investigate the influence of bioglass addition on the morphology, fiber diameter and composition of the membranes. The apatite-forming ability was examined in Simulated Body Fluid (SBF). The cytotoxicity of the membranes, ALP activity and in vitro mineralization were evaluated in cell culture. The mineralization and ALP activity was higher for polycaprolactone membranes modified with Zn doped bioglass than compared to pure PCL membranes or control material. The results proved that the presence of Zn 2+ in the electrospun membranes = influence the osteogenic differentiation of cells.

The aim of this work was to investigate of biocompatibility of polymeric implants modified with silver nanoparticles (AgNPs). Middle ear prostheses (otoimplants) made of the (poly)acrylonitrile butadiene styrene (ABS) and ABS modified with silver nanoparticles were prepared through extrusion and injection moulding process. The obtained prostheses were characterized by SEM-EDX, micro-CT and mechanical tests, confirming their proper shape, good AgNPs homogenization and mechanical parameters stability. The biocompatibility of the implants was evaluated in vivo on rats, after 4, 12, 24 and 48 weeks of implantation. The tissue-healing process and cytotoxicity of the implants were evaluated on the basis of microscopic observations of the materials morphology after histochemical staining with cytochrome c oxidase (OCC) and acid phosphatase (AP), as well as via micro-tomography (ex vivo). The in vivo studies confirmed biocompatibility of the implants in the surrounding tissue environment. Both the pure ABS and nanosilver-modified ABS implants exhibited a distinct decrease in the area of granulation tissue which was replaced with the regenerating muscle tissue. Moreover, a slightly smaller area of granulation tissue was observed in the surroundings of the silver-doped prosthesis than in the case of pure ABS prosthesis. The kinetics of silver ions releasing from implants was investigated by ICP-MS spectrometry. The measurement confirmed that concentration of the silver ions increased within the implant’s immersion period. Our results showed that middle ear implant with the nanoscale modification is biocompatible and might be used in ossicular reconstruction.

There is currently a growing demand for more effective thermal insulation materials with the best performance properties. This research paper presents the investigation results on the influence of two types of filler on the structure and properties of rigid polyurethane foam composites. Fly ash as a product of coal combustion in power plants and microspheres of 5, 10, 15, and 20 wt.%, were used as rigid polyurethane foams modifiers. The results of thermal analysis, mechanical properties testing, and cellular structure investigation performed for polyurethane composites show that the addition of fly ash, up to 10 wt.%, significantly improved the majority of the tested parameters. The use of up to 20 wt.% of microspheres improves the mechanical and thermal properties and thermal stability of rigid polyurethane foams.