Research progress and clinical translation of three-dimensional printed porous tantalum in orthopaedics

With continuous developments in additive manufacturing technology, tantalum (Ta) metal has been manufactured into orthopaedic implants with a variety of forms, properties and uses by three-dimensional printing. Based on extensive research in recent years, the design, processing and performance aspects of this new orthopaedic implant material have been greatly improved. Besides the bionic porous structure and mechanical characteristics that are similar to human bone tissue, porous tantalum is considered to be a viable bone repair material due to its outstanding corrosion resistance, biocompatibility, bone integration and bone conductivity. Numerous in vitro, in vivo, and clinical studies have been carried out in order to analyse the safety and efficacy of these implants in orthopaedic applications. This study reviews the most recent advances in manufacturing, characteristics and clinical application of porous tantalum materials.

Porous tantalum-composited gelatin nanoparticles hydrogel integrated with mesenchymal stem cell-derived endothelial cells to construct vascularized tissue in vivo

The ideal scaffold material of angiogenesis should have mechanical strength and provide appropriate physiological microporous structures to mimic the extracellular matrix environment.In this study,we constructed an integrated three-dimensional scaffold material using porous tantalum(pTa),gelatin nanoparticles(GNPs)hydrogel,and seeded with bone marrow mesenchymal stem cells(BMSCs)-derived endothelial cells(ECs)for vascular tissue engineering.The characteristics and biocompatibility of pTa and GNPs hydrogel were evaluated by mechanical testing,scanning electron microscopy,cell counting kit,and live-cell assay.The BMSCs-derived ECs were identified by flow cytometry and angiogenesis assay.BMSCs-derived ECs were seeded on the pTa-GNPs hydrogel scaffold and implanted subcutaneously in nude mice.Four weeks after the operation,the scaffold material was evaluated by histomorphology.The superior biocompatible ability of pTa-GNPs hydrogel scaffold was observed.Our in vivo results suggested that 28 days after implantation,the formation of the stable capillary-like network in scaffold material could be promoted significantly.The novel,integrated pTa-GNPs hydrogel scaffold is biocompatible with the host,and exhibits biomechanical and angiogenic properties.Moreover,combined with BMSCs-derived ECs,it could construct vascular engineered tissue in vivo.This study may provide a basis for applying pTa in bone regeneration and autologous BMSCs in tissue-engineered vascular grafts.

CYP3A4基因多态性对心脑血管疾病患者氯吡格雷响应影响的Meta分析

氯吡格雷是目前使用最广泛的P2Y12受体抑制剂之一。CYP3A4在氯吡格雷肝脏代谢中起重要作用。因此,CYP3A4基因多态性或许对服用氯吡格雷治疗的心脑血管疾病患者预测氯吡格雷疗效起重要作用。本研究对CYP3A4基因多态性对心脑血管疾病患者氯吡格雷响应的影响进行meta分析。对2019年10月7日之前发表在Pubmed、Embase、CochraneLibrary、clinicaltrail.gov、中国知网(CNKI)、万方数据库上的文献进行系统性检索,纳入评价CYP3A4不同突变型患者的血小板反应性与临床结局的队列研究或病例对照研究。使用ReviewManager软件进行数据分析,使用NOS量表评价纳入文献的质量。总共纳入18篇文献进行Meta分析。Meta分析结果显示,CYP3A4基因多态性对心脑血管疾病患者服用氯吡格雷后的血小板反应性无显著影响。同时,CYP3A4基因多态性对心脑血管疾病患者长期服用氯吡格雷后的结局无显著影响。

儿童福利机构中的类家庭养育

创设类家庭养育模式 类家庭养育与传统机构养育的不同 类家庭养育模式在很多方面的优势对幼童的健康成长是至关重要的。从结构角度来看，家庭由相对较小的团体构成，尤其是相对少的儿童。如果孩子不止一个，那么不同年龄、性别、或者有特殊需要的儿童都住在一起。

Materials evolution of bone plates for internal fixation of bone fractures:A review

Bone plates play a vital role in bone fracture healing by providing the necessary mechanical fixation for fracture fragments through modulating biomechanical microenvironment adjacent to the fracture site.Good treatment effect has been achieved for fixation of bone fracture with conventional bone plates,which are made of stainless steel or titanium alloy.However,several limitations still exist with traditional bone plates including loosening and stress shielding due to significant difference in modulus between metal material and bone tissue that impairs optimal fracture healing.Additionally,due to demographic changes and non-physiological loading,the population suffering from refractory fractures,such as osteoporosis fractures and comminuted fractures,is increasing,which imposes a big challenge to traditional bone plates developed for normal bone fracture repair.Therefore,optimal fracture treatment with adequate fixation implants in terms of materials and design relevant to special conditions is desirable.In this review,the complex physiological process of bone healing is introduced,followed by reviewing the development of implant design and biomaterials for bone plates.Finally,we discuss recent development of hybrid bone plates that contains bioactive elements or factors for fracture healing enhancement as a promising direction.This includes biodegradable Mg-based alloy used for designing bone screw-plates that has been proven to be beneficial for fracture healing,an innovative development that attracts more and more attention.This paper also indicates that the tantalum bone plates with porous structure are also emerging as a new fracture internal fixation implants.The reduction of the stress shielding is verified to be useful to accelerate bone fracture healing.Potential application of biodegradable metals may also avoid a second operation for implant removal.Further developments in biometals and their design for orthopedic bone plates are expected to improve the treatment of bone fracture,especially the refractory fractures.

Experimental study of a 3D printed permanent implantable porous Ta-coated bone plate for fracture fixation

Metal plates have always been the gold standard in the clinic for internal fracture fixation due to their high strength advantages.However,high elastic modulus can cause stress shielding and lead to bone embrittlement.This study used an electron beam melting method to prepare personalized porous Ti6Al4V(pTi)bone plates.Then,chemical vapor deposition(CVD)technology coats tantalum(Ta)metal on the pTi bone plates.The prepared porous Ta-coated bone plate has an elastic modulus similar to cortical bone,and no stress shielding occurred.In vitro experiments showed that compared with pTi plates,Ta coating significantly enhances the attachment and proliferation of cells on the surface of the scaffold.To better evaluate the function of the Ta-coated bone plate,animal experiments were conducted using a coat tibia fracture model.Our results showed that the Ta-coated bone plate could effectively fix the fracture.Both imaging and histological analysis showed that the Ta-coated bone plate had prominent indirect binding of callus formation.Histological results showed that new bone grew at the interface and formed good osseointegration with the host bone.Therefore,this study provides an alternative to bio-functional Ta-coated bone plates with improved osseointegration and osteogenic functions for orthopaedic applications.

Evaluation of the performance of Ca-deficient hydroxyapatite(CDHA)/MgF_(2)bilayer coating on biodegradable high-purity magnesium in a femoral condyle defect model in rabbits

The two most critical factors in promoting the clinical translation of magnesium(Mg)are reducing its degradation rate and improving its osteogenesis.In this study,a Ca-deficient hydroxyapatite(CDHA)/MgF_(2)bilayer coating was prepared on high-purity magnesium(HP Mg)rods by fluorination and hydrothermal treatment.Scanning electron microscope showed that the thickness of the bilayer coating was 3.78 lm and that the surface morphology was nanoscale.In an in vivo experiment on femoral condyle defects in rabbits,the serum magnesium ion levels of rabbits were always in the normal range after surgery,and the liver and kidney functions were not abnormal,which indicated that the CDHA/MgF_(2)bilayer coating has good biosafety.Micro-CT showed that the CDHA/MgF_(2)bilayer coating significantly reduced the degradation rate of the HP Mg rods and enhanced the promotion of bone formation.Hard tissue sections showed that the CDHA/MgF_(2)bilayer coating gave the bone tissue a tight contact interface with the HP Mg rod and improved the bone mass.Immunohistochemistry showed that the expression of vascular endothelial growth factor and BMP-2 was more obvious.These results confirm that the CDHA/MgF_(2)bilayer coating can improve the properties of HP Mg and provide a basis for the further transformation of HP Mg in the future.It also provides a new reference for the surface modification of magnesiummetal.