Biological Properties of Solid Free Form Designed Ceramic Scaffolds with BMP-2: In Vitro and In Vivo Evaluation

Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. Solid free form (SFF) fabrication methods allow fabrication of ceramic scaffolds with fully controlled pore architecture, which opens new perspectives in bone tissue regeneration materials. However, little experimentation has been performed about real biological properties and possible applications of SFF designed 3D ceramic scaffolds. Thus, here the biological properties of a specific SFF scaffold are evaluated first, both in vitro and in vivo, and later scaffolds are also implanted in pig maxillary defect, which is a model for a possible application in maxillofacial surgery. In vitro results show good biocompatibility of the scaffolds, promoting cell ingrowth. In vivo results indicate that material on its own conducts surrounding tissue and allow cell ingrowth, thanks to the designed pore size. Additional osteoinductive properties were obtained with BMP-2, which was loaded on scaffolds, and optimal bone formation was observed in pig implantation model. Collectively, data show that SFF scaffolds have real application possibilities for bone tissue engineering purposes, with the main advantage of being fully customizable 3D structures

Strength of aluminium titanate/mullite composites containing thermal stabilizers

[EN]This work contains a study on the room temperature-fracture strength of three aluminium titanate-based materials containing mullite and different thermal stabilizers (namely Fe2O3 and MgO). The highest inert strength was reached by the material sintered without any stabilizer. The MgO-doped material had a comparable inert strength, but a significantly higher Weibull modulus. Finally, the Fe2O3-doped material showed the worst mechanical properties. In all cases, a critical load above which strength degraded was apparent. These behaviours have been analyzed in terms of the type of additives and the particular microstructures. Conclusions about the potential use of these materials are briefly stated

Improving the compressive strength of bioceramic robocast scaffolds by polymer infiltration

[EN]The effect of polymer infiltration on the compressive strength of β-tricalcium phosphate (TCP) scaffolds fabricated by robocasting (direct write assembly) is analyzed in this work. Porous structures consisting of a tetragonal three-dimensional mesh of interpenetrating rods were fabricated from concentrated TCP inks with suitable viscoelastic properties. Biodegradable polymers (polylactic acid (PLA) and poly(ε-caprolactone) (PCL)) were infiltrated into selected scaffolds by immersion of the structure in a polymer melt. Infiltration increased the uniaxial compressive strength of these model scaffolds by a factor of three (PCL) or six (PLA). It also considerably improved the mechanical integrity of the structures after initial cracking, with the infiltrated structure retaining a significant load-bearing capacity after fracture of the ceramic rods. The strength improvement in the infiltrated scaffolds was attributed to two different contributions: the sealing of precursor flaws in the ceramic rod surfaces and the partial transfer of stress to the polymer, as confirmed by finite element analysis. The implications of these results for the mechanical optimization of scaffolds for bone tissue engineering applications are discussed

Battlebots: un proyecto piloto de ingeniería interdisciplinar basado en robótica electrónica

Memoria ID2022-026. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2022-2023

Innovación en la generación de materiales audiovisuales utilizando la "lightboard" para mejorar los procesos de enseñanza-aprendizaje en el grado de Ingeniería Mecánica

Memoria ID-023. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2021-2022

Prefabricated 3D-printed tissue-engineered bone for mandibular reconstruction: A preclinical translational study in primate

The advent of three dimensionally (3D) printed customized bone grafts using different biomaterials has enabled repairs of complex bone defects in various in vivo models. However, studies related to their clinical translations are truly limited. Herein, 3D printed poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PLGA/TCP) and TCP scaffolds with or without recombinant bone morphogenetic protein −2 (rhBMP-2) coating were utilized to repair primate’s large-volume mandibular defects and compared efficacy of prefabricated tissue-engineered bone (PTEB) over direct implantation (without prefabrication). 18F-FDG PET/CT was explored for real-time monitoring of bone regeneration and vascularization. After 3-month’s prefabrication, the original 3D-architecture of the PLGA/TCP-BMP scaffold was found to be completely lost, while it was properly maintained in TCP-BMP scaffolds. Besides, there was a remarkable decrease in the PLGA/TCP-BMP scaffold density and increase in TCP-BMP scaffolds density during ectopic (within latissimus dorsi muscle) and orthotopic (within mandibular defect) implantation, indicating regular bone formation with TCP-BMP scaffolds. Notably, PTEB based on TCP-BMP scaffold was successfully fabricated with pronounced effects on bone regeneration and vascularization based on radiographic, 18F-FDG PET/CT, and histological evaluation, suggesting a promising approach toward clinical translation.This work was supported by the National Natural Science Foundation of China [Grant No. 81671029], the National Major Science and Technology Project of China [Grant No. 2016YFC1102900], the Guangzhou Science, Technology and Innovation Commission [Grant Nos. 201803040008 and 201704030024], the International Team for Implantology [Grant No. 881_2012], the Bureau of Education of Guangzhou Municipality [Grant No. 1201610458], China Scholarship Council (No. 201908440308), Spanish Ministry of Science, Innovation and Universities [Grant No. RTI2018-095566–B-I00], and Junta de Extremadura [Grant No. IB16094]; the last two cofinanced with European Regional Development Funds.peerReviewe

Implantation in pig maxillary defects: Data.

<p>Table summarized data obtained from μCT studies (SFF, Robocast scaffolds; BIO, Bio-Oss). Graphic represent “Bone Volume” and “Bone Mineral Content” (BMC). Data in graphics are provided in mean and standard deviation. Significative differences stand for: * (p≤0.05), ** (p≤0.01), *** (p≤0.001).</p

SFF designed Scaffold.

<p>A) SEM micrographs of scaffold samples. A1) Entire scaffolds; A2) top plane view; A3) cross-section view. B) μCT images of scaffold samples. B1) Entire scaffolds; B2) top plane view; B3) cross-section view. Table shows measured structural data.</p

ALP activity measurements.

<p>Time course plot of ALP activity in control scaffolds (Control), BMP-2 adsorbed scaffolds (BMP-2) and Chitosan/BMP-2 coated scaffolds (CH/BMP-2).</p

Implantation in pig maxillary defects: materials and surgery.

<p>A) Robocast ceramic design, macroscopical appearance of scaffold and microscopical detail. B) Images of surgery procedure, implantation of a Robocast sample and fixation of it with screws. C) Microscopical image of a Bio-Oss® sample, detail of Bio-Oss® sample preparation procedure and Bio-Oss® implanted and fixated with surgical glue (see blue glue between sample and surrounding bone).</p