Fabrication of porous beta-tricalcium phosphate with microchannel and customized geometry based on gel-casting and rapid prototyping.

State Key Lab for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an, ShaanXi, People's Republic of China.
Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine (Impact Factor: 1.14). 03/2011; 225(3):315-23. DOI: 10.1243/09544119JEIM769
Source: PubMed

ABSTRACT The tissue engineering scaffolds with three-dimensional porous structure are regarded to be beneficial to facilitate a sufficient supply of nutrients and enable cell ingrowth in bone reconstruction. However, the pores in scaffolds tend to be blocked by the cell ingrowth and result in a restraint of nutrient supply in the further side of the scaffold. An indirect approach of combining the rapid prototyping and gel-casting technique is introduced in this study to fabricate beta-tricalcium phosphate (beta-TCP) scaffolds which not only have interconnected porous structure, but also have a microchannel network inside. The scaffold was designed with customized geometry that matches the defect area, and a double-scale (micropores-microchannel) porous structure inside that is beneficial for cell ingrowth. The scaffolds fabricated have an open, uniform, and interconnected porous architecture with a pore size of 200-400 microm, and posses an internal channel network with a diameter of 600 microm. The porosity was controllable. The compressive yield strength was 4.5 MPa with a porosity of 70 per cent. X-ray diffraction analysis shows that these fabrication processes do not change the crystal structure and chemical composition of beta-TCP. With this technique, it was also possible to fabricate porous scaffolds with desired pore size, porosity, and microchannel, as well as customized geometries by other bioceramics.

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    ABSTRACT: Loss of ligament graft tension in early postoperative stages following ACL reconstruction can come from a variety of factors, with slow graft integration to bone being widely viewed as a chief culprit. Toward an off-the-shelf ACL graft that can rapidly integrate to host tissue, we have developed a silk-based ACL graft combined with a TCP/PEEK anchor. In the present study we tested safety and efficacy of this concept in a porcine model, with postoperative assessments at 3 months (n = 10) and 6 months (n = 4). Biomechanical tests were performed after euthanization, with ultimate tensile strengths at 3 months of ∼370 N and ∼566 N at 6 months – comparable with autograft and allograft performance in this animal model. Comprehensive histological observations revealed that TCP substantially enhanced silk graft to bone attachment. Interdigitation of soft and hard tissues was observed, with regenerated fibrocartilage characterizing a transitional zone from silk graft to bone that was similar to native ligament bone attachments. We conclude that both initial stability and robust long-term biological attachment were consistently achieved using the tested construct, supporting a large potential for silk–TCP combinations in the repair of the torn ACL.
    Acta Biomaterialia 08/2014; 10(8):3696–3704. · 5.68 Impact Factor


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May 20, 2014