Polyetheretherketone bioactivity induced by farringtonite.

Polyetheretherketone (PEEK) is considered as an excellent biomaterial for bone grafting and connective tissue replacement. The clinical potential is, however, limited by its bioinertness, poor osteoconduction, and weak antibacterial activity. These disadvantages can be overcome by introducing suitable additives to produce mineral-polymer composites or coatings. In this work, a PEEK-based bioactive composite has been obtained by blending the polymer with magnesium phosphate (Mg3(PO4)2) particles in amounts ranging from 1 to 10 wt.% using the hot press technique. The obtained composite exhibited improved mechanical and physical properties, above the lower limits set for bone engineering applications. The tested grafts were found to not induce cytotoxicity. The presence of magnesium phosphate induced the mineralisation process with no adverse effects on the expression of the marker crucial for osteoblastic differentiation. The most promising results were observed in the grafts containing 1 wt.% of magnesium phosphate embedded within the PEEK matrix. The improved bioactivity of grafts, together with suitable physical-chemical and mechanical properties, indicate this composite as a promising orthopaedic implant material.

Method for in situ polypyrrole coating, and the example of its use for functionalization of polyurethane anisotropic electrospun mats.

The in situ coating of polymer substrate with polypyrrole, described herein with detailed know-how, represents a novel technique of surface functionalization. The choice of oxidizing agent and the polymerization time both affect the properties of the thin polypyrrole layer. The specific conductivity, free surface energy, thickness, topography, and FTIR spectra of polypyrrole layer were determined. The conductive coatings were further used to functionalize both isotropic and anisotropic electrospun polyurethane nanofibrous mats to show their applicability and study the bioactive effect of both the anisotropy and conductivity together. The morphology of composites was studied by means of atomic force microscopy and scanning electron microscopy. A complex cytocompatibility study was performed, including determining cytotoxicity by optical and fluorescence microscopy, the advanced qualification of cell morphology by cell-image analysis, and a study of stem cell behavior. The results clearly showed the significant impact of substrate modification on cells, especially on fibroblasts while the embryonic stem cells were less affected. This study shows not only the effective way to prepare a thin conducting layer based on polypyrrole but also demonstrates its importance for the fabrication of smart biomaterials.

Cross-Linked Gelatine by Modified Dextran as a Potential Bioink Prepared by a Simple and Non-Toxic Process.

Essential features of well-designed materials intended for 3D bioprinting via microextrusion are the appropriate rheological behavior and cell-friendly environment. Despite the rapid development, few materials are utilizable as bioinks. The aim of our work was to design a novel cytocompatible material facilitating extrusion-based 3D printing while maintaining a relatively simple and straightforward preparation process without the need for harsh chemicals or radiation. Specifically, hydrogels were prepared from gelatines coming from three sources-bovine, rabbit, and chicken-cross-linked by dextran polyaldehyde. The influence of dextran concentration on the properties of hydrogels was studied. Rheological measurements not only confirmed the strong shear-thinning behavior of prepared inks but were also used for capturing cross-linking reaction kinetics and demonstrated quick achievement of gelation point (in most cases < 3 min). Their viscoelastic properties allowed satisfactory extrusion, forming a self-supported multi-layered uniformly porous structure. All gelatin-based hydrogels were non-cytototoxic. Homogeneous cells distribution within the printed scaffold was confirmed by fluorescence confocal microscopy. In addition, no disruption of cells structure was observed. The results demonstrate the great potential of the presented hydrogels for applications related to 3D bioprinting.