Beijing Allgens Medical Science and Technology Co.

Beijing, China

Beijing Allgens Medical Science and Technology Co.

Beijing, China

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Guo W.-G.,Tsinghua University | Guo W.-G.,Beijing Allgens Medical Science and Technology Co. | Qiu Z.-Y.,Tsinghua University | Cui H.,Beijing Allgens Medical Science and Technology Co. | And 5 more authors.
Frontiers of Materials Science | Year: 2013

Dense hydroxyapatite (HA) ceramic is a promising material for hard tissue repair due to its unique physical properties and biologic properties. However, the brittleness and low compressive strength of traditional HA ceramics limited their applications, because previous sintering methods produced HA ceramics with crystal sizes greater than nanometer range. In this study, nano-sized HA powder was employed to fabricate dense nanocrystal HA ceramic by high pressure molding, and followed by a three-step sintering process. The phase composition, microstructure, crystal dimension and crystal shape of the sintered ceramic were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Mechanical properties of the HA ceramic were tested, and cytocompatibility was evaluated. The phase of the sintered ceramic was pure HA, and the crystal size was about 200 nm. The compressive strength and elastic modulus of the HA ceramic were comparable to human cortical bone, especially the good fatigue strength overcame brittleness of traditional sintered HA ceramics. Cell attachment experiment also demonstrated that the ceramics had a good cytocompatibility. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.


Lian X.-J.,Taiyuan University of Technology | Lian X.-J.,Tsinghua University | Qiu Z.-Y.,Tsinghua University | Wang C.-M.,Beijing Allgens Medical Science and Technology Co. | And 4 more authors.
Journal of Biomaterials and Tissue Engineering | Year: 2013

Hybrid bioceramics composed of nano-hydroxyapatite (HA) and various amount of nano-ZrO2 were prepared by two-step sintering method. In the hybrid bioceramics, crystallite sizes of HA is about 170 nanometers in the case of 10 wt% ZrO2. Elastic modulus, hardness and crystallite sizes of the hybrid bioceramics are decreased with the increase of proportion of nano-ZrO2. The cytocompatibility of the hybrid bioceramics was studied through SEM observation of osteoblast MC3T3-E1, showing similar cytocompatibility to pure nano-HA ceramics. Reasons for the modifications compared with pure nano-HA ceramics are discussed. © 2013 American Scientific Publishers, All rights reserved.


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.


Zhang X.,Shenyang University | Guo W.-G.,Beijing Allgens Medical Science and Technology Company | Cui H.,Beijing Allgens Medical Science and Technology Company | 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.


Jiang H.-J.,Wendeng Orthopaedic Hospital | Xu J.,Nanjing Medical University | Qiu Z.-Y.,Tsinghua University | Qiu Z.-Y.,Beijing Allgens Medical Science and Technology Co. | And 5 more authors.
Materials | Year: 2015

Polymethyl methacrylate (PMMA) bone cement is a commonly used bone adhesive and filling material in percutaneous vertebroplasty and percutaneous kyphoplasty surgeries. However, PMMA bone cements have been reported to cause some severe complications, such as secondary fracture of adjacent vertebral bodies, and loosening or even dislodgement of the set PMMA bone cement, due to the over-high elastic modulus and poor osteointegration ability of the PMMA. In this study, mineralized collagen (MC) with biomimetic microstructure and good osteogenic activity was added to commercially available PMMA bone cement products, in order to improve both the mechanical properties and the cytocompatibility. As the compressive strength of the modified bone cements remained well, the compressive elastic modulus could be significantly down-regulated by the MC, so as to reduce the pressure on the adjacent vertebral bodies. Meanwhile, the adhesion and proliferation of pre-osteoblasts on the modified bone cements were improved compared with cells on those unmodified, such result is beneficial for a good osteointegration formation between the bone cement and the host bone tissue in clinical applications. Moreover, the modification of the PMMA bone cements by adding MC did not significantly influence the injectability and processing times of the cement. © 2015 by the authors; licensee MDPI, Basel, Switzerland.


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.


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.


Patent
Beijing Allgens Medical Science and Technology Co. | Date: 2015-01-24

To cover shortages of existing PMMA bone cement products, including very high hardness and poor biocompatibility, the invention provides a mineralized collagen incorporated PMMA bone adhesive and filling material. Mineralized collagen (MC) is prepared via an in vitro biomimetic mineralization process and has a chemical composition and structure of self-assembled nano-sized calcium phosphate and collagen molecules, thus possessing biomimetic mineralized structure and mechanical properties similar to natural human bone, good biocompatibility, osteogenic activity and biodegradation ability. An MC incorporated bone adhesive and filling material with high compressive strength and low elastic modulus, and improved biocompatibility compared to pure PMMA bone cements may be obtained. Such bone adhesive and filling materials reduce the risk of abrading the host bone tissue and avoiding damage of the implant caused by extrusion, and form osteointegration with the host bone, improving the stability of the bone adhesive and filling materials at the implantation site.


PubMed | Beijing Allgens Medical Science and Technology Co., Tsinghua University, Beijing University of Chinese Medicine, China University of Science and Technology and 2 more.
Type: Journal Article | Journal: Regenerative biomaterials | Year: 2016

The purpose of this study was to explore the different effects between biomimetic mineralized collagen (MC) and ordinary physically blended hydroxyapatite/collagen (HA/Col) composite in evaluating new bone formation and regenerated bone height in human extraction sockets. Thirty-four patients who cannot retain teeth caused by trauma or decay were randomly selected from Department of Stomatology of Dongzhimen Hospital from December 2013 to December 2014. The patients were randomly divided into two groups. After the operation of tooth extraction, 17 patients were implanted with biomimetic MC (MC group), and other 17 patients were implanted with ordinary physically blended nHA/Col composite (nHA/Col group). X-ray positioning projection by auto-photographing was taken to test the distance between the lowest position and the neighboring CEJm-CEJd immediately, 1 month and 3 months after the operation. The height of new bone formation of the MC group was significantly higher than the nHA/Col group. Biomimetic MC showed better clinical outcomes in the bone formation for extraction site preservation and would have broad application prospect in the field of oral and maxillofacial surgeries.


PubMed | Tsinghua University, Beijing Allgens Medical Science and Technology Co. and Liaoning Medical University
Type: Journal Article | Journal: 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.

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