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Song T.,Shandong Provincial Hospital | Qiu Z.-Y.,Tsinghua University | Qiu Z.-Y.,Beijing Allgens Medical Science and Technology Co. | Cui F.-Z.,Tsinghua University
Frontiers of Materials Science | Year: 2015

Reconstruction of cranial defect is commonly performed in neurosurgical operations. Many materials have been employed for repairing cranial defects. In this paper, materials used for cranioplasty, including autografts, allografts, and synthetic biomaterials are comprehensively reviewed. This paper also gives future perspective of the materials and development trend of manufacturing process for cranioplasty implants. © 2015, Higher Education Press and Springer-Verlag Berlin Heidelberg.

Zhang C.,Shanghai JiaoTong University | Qiu Z.-Y.,Tsinghua University | Zhang W.-Q.,Sishui Peoples Hospital | Cui H.,Beijing Allgens Medical Science and Technology Co. | And 4 more authors.
Journal of Biomaterials and Tissue Engineering | Year: 2014

As the main inorganic component of natural bone, hydroxyapatite has good biocompatibility and osteoconductivity. Conventional sintered hydroxyapatite ceramics are too brittle and have low fatigue strength, thereby limiting their clinical applications. Nano-crystal hydroxyapatite (NHA) ceramic could be prepared by a two-step sintering process and overcomes the disadvantages of brittleness and low fatigue strength. The NHA ceramic provides good mechanical properties that meet the loadbearing requirement of human spine. In this study, animal experiments were performed to evaluate osteointegration and repair effect of the NHA ceramic spinal fusion cage. NHA ceramics intervertebral fusion cages were prepared and implanted into L6-L7 and L7-S1 intervertebral spaces of beagle dogs. The spinal fusion efficacy was evaluated by X-ray imaging and histological observations 2 months and 6 months post-operation. The results showed that the cages and the endplates of the vertebral bodies fused very well 6 months post-operation. Disc space heights were enlarged by the implantation and were not lost post-operation. Histological observations indicated obvious osteointegrations between the implants and the host bone. With good biocompatibility, bioactivity and mechanical strength, NHA is a promising bone substitution material and has a broad application prospect in the field of spinal intervertebral fusion cage. © 2014 American Scientific Publishers All rights reserved.

Zhang X.,Shenyang University | Guo W.-G.,Beijing Allgens Medical Science and Technology Co. | Cui H.,Beijing Allgens Medical Science and Technology Co. | Liu H.-Y.,Shenyang University | And 3 more authors.
Journal of Tissue Engineering and Regenerative Medicine | Year: 2016

Enhancement of osteogenic capacity was achieved in a mineralized collagen composite, nano-hydroxyapatite/collagen (nHAC), by loading with synthetic peptides derived from BMP-2 residues 32-48 (P17-BMP-2). Rabbit marrow stromal cells (MSCs) were used in vitro to study cell biocompatibility, attachment and differentiation on the mineralized collagen composite by a cell counting kit, scanning electron microscopy (SEM) and real-time reversed transcriptase-polymerase chain reaction analysis (RT-PCR). Optimal peptide dosage (1.0μg/mL) was obtained by RT-PCR analysis in vitro. In addition, the relative expression level of OPN and OCN was significantly upregulated on P17-BMP-2/nHAC compared with nHAC. In vitro results of P17-BMP-2 release kinetics demonstrated that nHAC released P17-BMP-2 in a controlled and sustained manner. In the rabbit mandibular box-shaped bone defect model, osteogenic capacity of three groups (nHAC, P17-BMP-2/nHAC, rhBMP-2/nHAC) was evaluated. Compared to the nHAC group, bone repair responses in both P17-BMP-2/nHAC and rhBMP-2/nHAC group implants were significantly improved based on histological analysis. The osteogenic response of the P17-BMP-2/nHAC group was similar to that of the rhBMP-2/nHAC group. © 2016 John Wiley & Sons, Ltd.

Sun Y.,Liaoning Medical University | Wang C.-Y.,Liaoning Medical University | Wang Z.-Y.,Liaoning Medical University | Cui Y.,Beijing Allgens Medical Science and Technology Co. | And 4 more authors.
Journal of Biomaterials Applications | Year: 2016

The aim of this study was to discuss the feasibility of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration membrane in site preservation in extraction sockets. The third mandibular premolars on both sides were extracted from four dogs, thus there were 16 alveolar sockets in all dogs and were randomly assigned into three groups. Group A had six alveolar sockets, and groups B and C had five alveolar sockets, respectively. Each alveolar socket of group A was immediately implanted with a porous mineralized collagen plug and covered with a bilayer mineralized collagen-guided bone regeneration membrane after tooth extraction. Alveolar sockets of group B were implanted with porous mineralized collagen plug only, and group C was set as blank control without any implantation. The healing effects of the extraction sockets were evaluated by gross observation, morphological measurements, and X-ray micro-computed tomography after twelve weeks. Twelve weeks after operation, both groups A and B had more amount of new bone formation compared with group C; in terms of the degree of alveolar bone height, group A was lower than groups B and C with significant differences; the bone mineral density in the region of interest and bone remodeling degree in group A were higher than those of groups B and C. As a result, porous mineralized collagen plug could induce the regeneration of new bone in extraction socket, and combined use of porous mineralized collagen plug and bilayer mineralized collagen guided bone regeneration membrane could further reduce the absorption of alveolar ridge and preserve the socket site. © SAGE Publications 2015.

Qiu Z.-Y.,Tsinghua University | Tao C.-S.,Tsinghua University | Cui H.,Beijing Allgens Medical Science and Technology Co. | Wang C.-M.,Beijing Allgens Medical Science and Technology Co. | Cui F.-Z.,Tsinghua University
Frontiers of Materials Science | Year: 2014

Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites. © 2014 Higher Education Press and Springer-Verlag Berlin Heidelberg.

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