Incorporation of metal-doped silicate microparticles into collagen scaffolds combines chemical and architectural cues for endochondral bone healing.

Regeneration of large bone defects remains a clinical challenge until today. While existing biomaterials are predominantly addressing bone healing via direct, intramembranous ossification (IO), bone tissue formation via a cartilage phase, so-called endochondral ossification (EO) has been shown to be a promising alternative strategy. However, pure biomaterial approaches for EO induction are sparse and the knowledge how material components can have bioactive contribution to the required cartilage formation is limited.

Poly(dl-lactide) Polymer Blended with Mineral Phases for Extrusion 3D Printing-Studies on Degradation and Biocompatibility.

A promising therapeutic option for the treatment of critical-size mandibular defects is the implantation of biodegradable, porous structures that are produced patient-specifically by using additive manufacturing techniques. In this work, degradable poly(DL-lactide) polymer (PDLLA) was blended with different mineral phases with the aim of buffering its acidic degradation products, which can cause inflammation and stimulate bone regeneration. Microparticles of CaCO, SrCO, tricalcium phosphates (α-TCP, β-TCP), or strontium-modified hydroxyapatite (SrHAp) were mixed with the polymer powder following processing the blends into scaffolds with the Arburg Plastic Freeforming 3D-printing method.

A comparative analysis of 3D printed scaffolds consisting of poly(lactic--glycolic) acid and different bioactive mineral fillers: aspects of degradation and cytocompatibility.

Their excellent mechanical properties, degradability and suitability for processing by 3D printing technologies make the thermoplastic polylactic acid and its derivatives favourable candidates for biomaterial-based bone regeneration therapies. In this study, we investigated whether bioactive mineral fillers, which are known to promote bone healing based on their dissolution products, can be integrated into a poly(L-lactic--glycolic) acid (PLLA-PGA) matrix and how key characteristics of degradation and cytocompatibility are influenced. The polymer powder was mixed with particles of CaCO, SrCO, strontium-modified hydroxyapatite (SrHAp) or tricalcium phosphates (α-TCP, β-TCP) in a mass ratio of 90 : 10; the resulting composite materials have been successfully processed into scaffolds by the additive manufacturing method Arburg Plastic Freeforming (APF).

Bone regeneration capacity of newly developed spherical magnesium phosphate cement granules.

Objectives: Magnesium phosphate-based cements begin to catch more attention as bone substitute materials and especially as alternatives for the more commonly used calcium phosphates. In bone substitutes for augmentation purposes, atraumatic materials with good biocompatibility and resorbability are favorable. In the current study, we describe the in vivo testing of novel bone augmentation materials in form of spherical granules based on a calcium-doped magnesium phosphate (CaMgP) cement.

Development and Bone Regeneration Capacity of Premixed Magnesium Phosphate Cement Pastes.

Magnesium phosphate cements (MPC) have been demonstrated to have a superior bone regeneration capacity due to their good solubility under in vivo conditions. While in the past only aqueous MPC pastes have been applied, the current study describes the fabrication and in vitro/in vivo testing of an oil-based calcium doped magnesium phosphate (CaMgP) cement paste. Premixed oil-based pastes with CaMgP chemistry combine the advantages of conventional MPC such as high mechanical strength and good resorbability with a prolonged shelf-life and an easier clinical handling.

Prefabricated and Self-Setting Cement Laminates.

Polycaprolactone (PCL) fiber mats with defined pore architecture were shown to provide sufficient support for a premixed calcium phosphate cement (CPC) paste to serve as a flat and flexible composite material for the potential application in 2-dimensional, curved cranial defects. Fiber mats were fabricated by either melt electrospinning writing (MEW) or solution electrospinning (SES) with a patterned collector. While MEW processed fiber mats led to a deterioration of the cement bending strength by approximately 50%, due to a low fiber volume content in conjunction with a weak fiber-matrix interface, fiber mats obtained by solution electrospinning resulted in a mechanical reinforcement of the cement matrix in terms of both bending strength and absorbed fracture energy.

Strontium(II) and mechanical loading additively augment bone formation in calcium phosphate scaffolds.

Calcium phosphate cements (CPCs) are widely used for bone-defect treatment. Current developments comprise the fabrication of porous scaffolds by three-dimensional plotting and doting using biologically active substances, such as strontium. Strontium is known to increase osteoblast activity and simultaneously to decrease osteoclast resorption.

The effect of oligo(trimethylene carbonate) addition on the stiffness of acrylic bone cement.

With the increasing elderly population an increase in the number of bony fractures associated to age-related diseases such as osteoporosis also follows. The relatively high stiffness of the acrylic bone cements used in these patients has been suggested to give raise to a suboptimal load distribution surrounding the cement in vivo, and hence contribute to clinical complications, such as additional fractures. The aim of this study was to develop a low-modulus bone cement, based on currently used, commercially available poly(methyl methacrylate) (PMMA) cements for vertebroplasty.

The influence of Sr content in calcium phosphate coatings.

In this study calcium phosphate coatings with different amounts of strontium (Sr) were prepared using a biomineralization method. The incorporation of Sr changed the composition and morphology of coatings from plate-like to sphere-like morphology. Dissolution testing indicated that the solubility of the coatings increased with increased Sr concentration.

Effects of nanoporous alumina on inflammatory cell response.

The present study focuses on the effects of nanoscale porosity on inflammatory response in vitro and in vivo. Nanoporous alumina membranes with different pore sizes, 20 and 200 nm in diameter, were used. We first evaluated cell/alumina interactions in vitro by observing adhesion, proliferation, and activation of a murine fibroblast and a macrophage cell line.

Self-supporting nanoporous alumina membranes as substrates for hepatic cell cultures.

Membranes made from nanoporous alumina exhibit interesting properties for their use in biomedical research. They show high porosity and the pore diameters can be easily adjusted in a reproducible manner. Nanoporous alumina membranes are thus ideal substrates for the cultivation of polar cells (e.

Role of alumina nanoporosity in acute cell response.

This work studied the effect of nanoporous alumina in acute cellular response in an in vivo model. Nanoporous alumina membranes, with pore size diameters of 20 and 200 nm, were fabricated by anodic oxidation of aluminium. The membranes were thereafter characterized in terms of pore size distribution and chemical composition.

Mesoporous titanium dioxide coating for metallic implants.

A bioactive mesoporous titanium dioxide (MT) coating for surface drug delivery has been investigated to develop a multifunctional implant coating, offering quick bone bonding and biological stability. An evaporation induced self-assembly (EISA) method was used to prepare a mesoporous titanium dioxide coating of the anatase phase with BET surface area of 172 m(2)/g and average pore diameter of 4.3 nm.

Investigation of cell-substrate interactions by focused ion beam preparation and scanning electron microscopy.

Cell-substrate interactions, which are an important issue in tissue engineering, have been studied using focused ion beam (FIB) milling and scanning electron microscopy (SEM). Sample cross-sections were generated at predefined positions (target preparation) to investigate the interdependency of growing cells and the substrate material. The experiments focus on two cell culturing systems, hepatocytes (HepG2) on nanoporous aluminum oxide (alumina) membranes and mouse fibroblasts (L929) and primary nerve cells on silicon chips comprised of microneedles.

Low-modulus PMMA bone cement modified with castor oil.

Some of the current clinical and biomechanical data suggest that vertebroplasty causes the development of adjacent vertebral fractures shortly after augmentation. These findings have been attributed to high injection volumes as well as high Young's moduli of PMMA bone cements compared to that of the osteoporotic cancellous bone. The aim of this study was to evaluate the use of castor oil as a plasticizer for PMMA bone cements.