Papers by Author: Ke Ya Mao

Abstract: An ideal injectable bone cement should be able to fill fully the fractures gap and provide good mechanical support. In the present work, the mineralized collagen and calcium sulphate dehydrate (CSD) was incorporated into α-calcium sulphate hemihydrates (α-CSH) to explore an injectable composite cement. The injectability, the setting time and the biomechanics properties were investigated. A porcine thoracolumbar burst fracture model was used to evaluate the biomechanical performance of composite cements. The porcine thoracolumbar burst fracture models in vitro were prepared. A half of models was made by the vertebroplasty of the composite cements, the other half of models was used as control. Imaging analysis showed the composite cements distributed uniformly and solidified well. Biomechanical test showed the ability of the composite cements to repair spinal burst fractures was significant.

Abstract: The need for bone repair has increased as the population ages. However, currently, the bone grafts still have some disadvantages, such as low compressive strength and porosity, which limit their use. In order to solve these disadvantages, in this study, the porous beta-tricalcium phosphate (β-TCP) anorganic bone graft were prepared from healthy bovine cancellous bone by cell-free, defat and twice calcinations. X-ray diffraction (XRD) was used to investigate the chemical composition of the bone graft. And the morphology, porosity and mechanical strength of the bone graft were also evaluated. The results showed that most constituent of the bone graft was β-TCP. In addition, the bone graft scaffold exhibited the macro and micro porous structure and the porosity was 57.63%, just as the nature cancellous bone. The compressive strength was 4.47±0.63MPa. Above all, the porous β-TCP anorganic bone graft not only has similar chemical composites as the nature cancellous bone, but also it can effectively retain the porous structure of natural cancellous bone and provides optimal channels for the ingrowth of new bone and blood vessels.Therefore, the porous β-TCP anorganic bone graft is a potential biomaterial in bone tissue engineering.

Abstract: To explore a new type of injectable composite cements similar to the natural bone in both composition and hierarchical structure, the mineralized collagen and calcium sulphate dihydrate（CSD）were incorporated into α-calcium sulphate hemihydrate (α-CSH).The mineralized collagen was synthesized biomimetically by nanohydroxyapatite/collagen. We investigated the injectability, the setting time and the biomechanics properties to find an ideal combination of them to prepare the composite cements. SEM analysis showed biphasic cements consisting of an entanglement of calcium sulfate dihydrate and calcium-deficient hydroxyapatite crystals. We prepared porcine thoracolumbar burst fracture models and made the vertebroplasty for them by the composite cements. Imaging analysis showed the composite cements distributed uniformly and solidified well. Biomechanical test showed the ability of composite cements to repair spinal burst fractures was significant.

Abstract: Every year, roughly two million patients worldwide sustain a bone grafting procedure to repair bone defects stemming from tumor, the wound, the infection, as well as other reasons [1, 2]. The bone transplantation is one of main methods to treat bone damages [3]. The gold standard is to use autologous bone or autograft [4]. However, both the need of the second surgery and morbidity at the extraction site [5-7] has been an incentive to search for alternative treatment. One of them is to form bone graft bone. Many materials have been widely chosen to form bone graft substitutes: metals, polymers, ceramics, dehydrate, and calcium phosphates [8-13]. Although these synthetic materials provide an immediate solution for many patients, their long-term performance is generally not satisfactory. This is often due to a mechanical property mismatch between the implant failure and tissue damage [14, 15]. The development of combined artificial bone with improved mechanical properties and enhanced biocompatibility calls for a biomimetic approach using natural bone as a guide.

Abstract: In this paper, the combined artificial bone made from α- calcium sulphate hemihydrate（α-CSH） and β- tricalcium phosphate (β-TCP) was investigated and at the same time the study explored: the method of preparing the combined artificial bone. Scanning electron microscopy (SEM), Powder X-ray diffraction (XRD), Thermogravimetric (TG), Differential scanning calorimetry (DSC), and Mercury porosimeter were employed to characterize the samples. Results indicate that the combined artificial bone can be prepared by α-CSH and β-TCP using dehydrated alcohol as a solvent; β-TCP was made from cancellous bone in the femur of cattle under special conditions, which contained the spatial structure of normal cancellous bone; α-CSH was made from CSD under special temperature and pressure, which is more pure and regulation in crystal form.