In Vivo Investigation of 3D-Printed Calcium Magnesium Phosphate Wedges in Partial Load Defects.

Bone substitutes are ideally biocompatible, osteoconductive, degradable and defect-specific and provide mechanical stability. Magnesium phosphate cements (MPCs) offer high initial stability and faster degradation compared to the well-researched calcium phosphate cements (CPCs). Calcium magnesium phosphate cements (CMPCs) should combine the properties of both and have so far shown promising results.

Physicochemical degradation of calcium magnesium phosphate (stanfieldite) based bone replacement materials and the effect on their cytocompatibility.

Regenerative bone implants should be completely replaced by new bone within a period of time corresponding to the growth rate of native bone. To meet this requirement, suitable biomaterials must be biodegradable and promote osteogenesis. The combination of slowly degrading but osteoconductive calcium phosphates (CPs) with rapidly degrading and mechanically more resilient magnesium phosphates represents a promising material class for this purpose.

Comparison of degradation behavior and osseointegration of 3D powder-printed calcium magnesium phosphate cement scaffolds with alkaline or acid post-treatment.

Due to the positive effects of magnesium substitution on the mechanical properties and the degradation rate of the clinically well-established calcium phosphate cements (CPCs), calcium magnesium phosphate cements (CMPCs) are increasingly being researched as bone substitutes. A post-treatment alters the materials' physical properties and chemical composition, reinforcing the structure and modifying the degradation rate. By alkaline post-treatment with diammonium hydrogen phosphate (DAHP, (NH)HPO), the precipitation product struvite is formed, while post-treatment with an acidic phosphate solution [e.

Corrigendum to "Degradation of 3D-printed magnesium phosphate ceramics in vitro and a prognosis on their bone regeneration potential" [Bioact. Mater. 19 (2023) 376-391/22].

[This corrects the article DOI: 10.1016/j.bioactmat.

Degradation of 3D-printed magnesium phosphate ceramics and a prognosis on their bone regeneration potential.

Regenerative bone implants promote new bone formation and ideally degrade simultaneously to osteogenesis. Although clinically established calcium phosphate bone grafts provide excellent osseointegration and osteoconductive efficacy, they are limited in terms of bioresorption. Magnesium phosphate (MP) based ceramics are a promising alternative, because they are biocompatible, mechanically extremely stable, and degrade much faster than calcium phosphates under physiological conditions.

3D-Printed Regenerative Magnesium Phosphate Implant Ensures Stability and Restoration of Hip Dysplasia.

Osteoarthritis of the hip is a painful and debilitating condition commonly occurring in humans and dogs. One of the main causes that leads to hip osteoarthritis is hip dysplasia. Although the current surgical methods to correct dysplasia work satisfactorily in many circumstances, these are associated with serious complications, tissue resorption, and degeneration.

In-Vivo Degradation Behavior and Osseointegration of 3D Powder-Printed Calcium Magnesium Phosphate Cement Scaffolds.

Calcium magnesium phosphate cements (CMPCs) are promising bone substitutes and experience great interest in research. Therefore, in-vivo degradation behavior, osseointegration and biocompatibility of three-dimensional (3D) powder-printed CMPC scaffolds were investigated in the present study. The materials Mg225 (CaMg(PO)) and Mg225d (Mg225 treated with diammonium hydrogen phosphate (DAHP)) were implanted as cylindrical scaffolds (h = 5 mm, Ø = 3.

Tough magnesium phosphate-based 3D-printed implants induce bone regeneration in an equine defect model.

One of the important challenges in bone tissue engineering is the development of biodegradable bone substitutes with appropriate mechanical and biological properties for the treatment of larger defects and those with complex shapes. Recently, magnesium phosphate (MgP) doped with biologically active ions like strontium (Sr) have shown to significantly enhance bone formation when compared with the standard calcium phosphate-based ceramics. However, such materials can hardly be shaped into large and complex geometries and more importantly lack the adequate mechanical properties for the treatment of load-bearing bone defects.

Effect of strontium substitution on the material properties and osteogenic potential of 3D powder printed magnesium phosphate scaffolds.

3D powder printing is a versatile method for the fabrication of individual bone implants and was used for the processing of in vivo degradable ceramic scaffolds based on ammonium magnesium phosphate hexahydrate (struvite). In this study, synergetic effects could be achieved by the substitution of magnesium phosphate cements with strontium carbonate. This substitution resulted in 8.

Artificial inorganic biohybrids: The functional combination of microorganisms and cells with inorganic materials.

Unlabelled: Biohybrids can be defined as the functional combination of proteins, viable cells or microorganisms with non-biological materials. This article reviews recent findings on the encapsulation of microorganisms and eukaryotic cells in inorganic matrices such as silica gels or cements. The entrapment of biological entities into a support material is of great benefit for processing since the encapsulation matrix protects sensitive cells from shear forces, unfavourable pH changes, or cytotoxic solvents, avoids culture-washout, and simplifies the separation of formed products.

Computational design and fabrication of a novel bioresorbable cage for tibial tuberosity advancement application.

Tibial tuberosity advancement (TTA) is a promising method for the treatment of cruciate ligament rupture in dogs that usually implies the implantation of a titanium cage as bone implant. This cage is non-biodegradable and fails in providing adequate implant-bone tissue integration. The objective of this work is to propose a new process chain for designing and manufacturing an alternative biodegradable cage that can fulfill specific patient requirements.

In situ-immobilization of two model cyanobacterial strains in ceramic structures: A new biohybrid material for photobioreactor applications.

Two cyanobacterial strains, Synechocystis sp. PCC 6803 and Nostoc punctiforme ATCC 29133 were immobilized within magnesium phosphate based cements, showing a viability and activity for at least 4 weeks. These biohybrids are considered as an alternative photobioreactor material for bioremediation or an improved yield of biotechnologically relevant molecules.

Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing.

The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer-ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked.

Application of a 3D printed customized implant for canine cruciate ligament treatment by tibial tuberosity advancement.

Fabrication of customized implants based on patient bone defect characteristics is required for successful clinical application of bone tissue engineering. Recently a new surgical procedure, tibial tuberosity advancement (TTA), has been used to treat cranial cruciate ligament (CrCL) deficient stifle joints in dogs, which involves an osteotomy and the use of substitutes to restore the bone. However, limitations in the use of non-biodegradable implants have been reported.

Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects.

The 3D printing technique based on cement powders is an excellent method for the fabrication of individual and complex bone substitutes even in the case of large defects. The outstanding bone remodeling capacity of biphasic calcium phosphates (BCPs) containing hydroxyapatite (HA) as well as tricalcium phosphate (TCP) in varying ratios makes the adaption of powder systems resulting in BCP materials to this fabrication technique a desirable aim. This study presents the synthesis and characterization of a novel powder system for the 3D printing process, intended for the production of complexly shaped BCP scaffolds by a hydraulic setting reaction of calcium carbonate and TCP with phosphoric acid.

Fabrication of computationally designed scaffolds by low temperature 3D printing.

The development of artificial bone substitutes that mimic the properties of bone and simultaneously promote the desired tissue regeneration is a current issue in bone tissue engineering research. An approach to create scaffolds with such characteristics is based on the combination of novel design and additive manufacturing processes. The objective of this work is to characterize the microstructural and the mechanical properties of scaffolds developed by coupling both topology optimization and a low temperature 3D printing process.

Structural changes to resorbable calcium phosphate bioceramic aged in vitro.

This work investigates the effect of mammalian cell culture conditions on 3D printed calcium phosphate scaffolds. The purpose of the studies presented was to characterise the changes in scaffold properties in physiologically relevant conditions. Differences in crystal morphologies were observed between foetal bovine serum-supplemented media and their unsupplemented analogues, but not for supplemented media containing tenocytes.

Low temperature fabrication of spherical brushite granules by cement paste emulsion.

Secondary protonated calcium phosphates such as brushite (CaHPO(4)·2H(2)O) or monetite (CaHPO(4)) have a higher resorption potential in bone defects than sintered ceramics, e.g. tricalcium phosphate or hydroxyapatite.

The effect of Cu(II)-loaded brushite scaffolds on growth and activity of osteoblastic cells.

Bone substitute materials such as calcium phosphate cements (CPC) are frequently used as growth factor carriers for the stimulation of osteoblast-formation around an implant. However, biological modification based on delicate protein factors like extracellular matrix proteins or growth factors is subject to a number of shortcomings like the need for storage below room temperature and cost of production. The aim of this study was to investigate ionic modification as an alternative bioinorganic route for implant modification.

The effect of porosity on drug release kinetics from vancomycin microsphere/calcium phosphate cement composites.

The influence of porosity on release profiles of antibiotics from calcium phosphate composites was investigated to optimize the duration of treatment. We hypothesized, that by the encapsulation of vancomycin-HCl into biodegradable microspheres prior admixing to calcium phosphate bone cement, the influence of porosity of the cement matrix on vancomycin release could be reduced. Encapsulation of vancomycin into a biodegradable poly(lactic co-glycolic acid) copolymer (PLGA) was performed by spray drying; drug-loaded microparticles were added to calcium phosphate cement (CPC) at different powder to liquid ratios (P/L), resulting in different porosities of the cement composites.

Formation and properties of magnesium-ammonium-phosphate hexahydrate biocements in the Ca-Mg-PO4 system.

Calcium substituted trimagnesium phosphate with the general formula Ca(x)Mg((3-x))(PO(4))(2) (0 < x < 1.5) was synthesized by calcination of powder mixtures with the appropriate stoichiometry and reacted with 3.5 M diammonium hydrogenphosphate solution to form a cementitious matrix of magnesium ammonium phosphate hexahydrate (struvite).

Mechanical properties and drug release behavior of bioactivated PMMA cements.

Septic loosening of cemented implants represents an unresolved long-term problem of total hip endoprostheses. Common treatments of infected prostheses involve the use of temporary antibiotic-loaded PMMA spacer-implants or antibiotic-loaded cements. The latter are either provided by a manufacturer or are obtained by simply mixing specific antibiotic powders according to a microbial sensitivity test with PMMA cement.

Low temperature fabrication of magnesium phosphate cement scaffolds by 3D powder printing.

Synthetic bone replacement materials are of great interest because they offer certain advantages compared with organic bone grafts. Biodegradability and preoperative manufacturing of patient specific implants are further desirable features in various clinical situations. Both can be realised by 3D powder printing.

3D powder printed calcium phosphate implants for reconstruction of cranial and maxillofacial defects.

Background: The aim of this study was to investigate the processing and the possible use of 3D powder printed calcium phosphate implants for the reconstruction of cranial and maxillofacial defects.

Materials: The fabrication of the implants was carried out with a commercial 3D powder printing system. Diluted phosphoric acid was printed onto tricalcium phosphate powder, leading to the formation of dicalcium phosphate dihydrate (Brushite).

Angiogenesis in calcium phosphate scaffolds by inorganic copper ion release.

Angiogenesis in a tissue-engineered device may be induced by incorporating growth factors (e.g., vascular endothelial growth factor [VEGF]), genetically modified cells, and=or vascular cells.