摘要：Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering *** present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue *** experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and *** resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)*** studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural *** scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue *** tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of *** enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue *** vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold *** addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its pote

摘要：It has been hypothesized that leaflet substrates with a trilayer structure and anisotropicmechanical properties could be useful for the production of functional and long-lasting tissue-engineered *** investigate the influence of the anisotropic structural and mechanical characteristics of a substrate on cells,in this study,we electrospun trilayer anisotropic fibrous substrates and randomly oriented isotropic fibrous substrates(used as controls)from polycaprolactone ***,the random substrates had higher radial and lower circumferential tensile properties than the trilayer substrates;however,they had similar flexural *** valvular interstitial cells cultured on both substrates produced random and trilayer cell-cultured constructs,*** trilayer cell-cultured constructs had more anisotropic mechanical properties,17%higher cellular proliferation,14%more extracellular matrix(i.e.,collagen and glycosaminoglycan)production,and superior gene and protein expression,suggesting that more cells were in a growth state in the trilayer constructs than in the random ***,the random and radial layers of the trilayer constructs had more vimentin,collagen,transforming growth factor-beta 1(TGF-ß1),transforming growth factor-beta 3(TGF-ß3)gene expression than in the circumferential layer of the *** study verifies that the differences in structural,tensile,and anisotropic properties of the trilayer and random substrates influence the characteristics of the cells and ECM in the constructs.

摘要：The fields of regenerative medicine and tissue engineering offer new therapeutic options to restore,maintain or improve tissue function following disease or *** maximize the biological function of a tissue-engineered clinical product,specific conditions must be maintained within a bioreactor to allow the maturation of the product in preparation for ***,the bioreactor should be designed to mimic the mechanical,electrochemical and biochemical environment that the product will be exposed to in ***-time monitoring of the functional capacity of tissue-engineered products during manufacturing is a critical component of the quality management *** present review provides a brief overview of bioreactor engineering *** addition,strategies for bioreactor automation,in-line product monitoring and quality assurance are discussed.

摘要：The organized alignment of cells in various tissues plays a significant role in the maintenance of specific *** induce such an alignment,ideal scaffolds should simulate the characteristics and morphologies of natural *** structures that guide cell orientation are used to facilitate tissue regeneration and *** here review how various aligned structures are fabricated,including aligned electrospun nanofibers,aligned porous or channeled structures,micropatterns and combinations thereof,and their application in nerve,skeletal muscle,tendon,and tubular dentin *** future use of aligned structures in tissue engineering is also discussed.

摘要：tissue engineering is an emerging means for resolving the problems of tissue repair and organ replacement in regenerative *** supply of nutrients and oxygen to cells in large-scale tissues has led to the demand to prepare blood ***-based tissue engineering approaches are effective methods to form new blood vessel *** demand for blood vessels prompts systematic research on fabrication strategies of vascular scaffolds for tissue *** advances in 3D printing have facilitated fabrication of vascular scaffolds,contributing to broad prospects for tissue *** review presents state of the art on modeling methods,print materials and preparation processes for fabrication of vascular scaffolds,and discusses the advantages and application fields of each ***,significance and importance of scaffold-based tissue engineering for vascular regeneration are *** materials and preparation processes are discussed in *** a focus is placed on preparation processes based on 3D printing technologies and traditional manufacturing technologies including casting,electrospinning,and Lego-like *** related studies are *** of vascular scaffolds to clinical application is ***,four trends of 3D printing of tissue engineering vascular scaffolds are presented,including machine learning,near-infrared photopolymerization,4D printing,and combination of self-assembly and 3D printing-based methods.

摘要：Three-dimensional(3D)bioprinting has been used widely for the construction of hard tissues such as bone and ***,constructing soft tissues with complex structures remains a *** this study,complex structures characterized by both tunable elastic modulus and porosity were printed using freeform reversible embedding of suspended hydrogels(FRESHs)printing methods.A mixture of alginate and gelatin was used as the main functional component of the *** analysis showed that this bioink possesses shear thinning and shear recovery properties,supporting both cryogenic and FRESH printing *** printing capabilities and limitations of cryogenic and FRESH printing were then analyzed by printability tests.A series of complex structures were printed by FRESH printing methods which could not be realized using conventional *** tests and scanning electron microscopy analysis showed that the printed structure is of excellent flexibility and could be applied in various conditions by adjusting its mechanical modulus and porosity.L929 fibroblast cells maintained cell viability in cell-laden-printed structures,and the addition of collagen further improved the hydrogels’***,all results provided useful insight into the building of human soft tissue organ blocks.

摘要：Bone cancer is a critical health problem on a global scale,and the associated huge clinical and economic burdens are still *** many clinical approaches are currently used for bone cancer treatment,these methods usually affect the normal body functions and thus present significant ***,advanced materials and additive manufacturing have opened up promising avenues for the development of new strategies targeting both bone cancer treatment and post-treatment bone *** paper presents a comprehensive review of bone cancer and its current treatment methods,particularly focusing on a number of advanced strategies such as scaffolds based on advanced functional materials,drug-loaded scaffolds,and scaffolds for photothermal/magnetothermal ***,the main research challenges and future perspectives are elaborated.

摘要：Large bone defect regeneration has always been recognized as a challenging clinical problem due to the difficulty of *** treatments exhibit certain inherent disadvantages(e.g.,secondary injury,immunization,and potential infections).However,three-dimensional(3D)printing technology as an emerging field can serve as an effective approach to achieve satisfactory revascularization while making up for the above limitations.A wide variety of methods can be used to facilitate blood supply during the design of a 3D-printed ***,the scaffold structure lays a foundation for the entire printing object;any method to promote angiogenesis can be effective only if it is based on well-designed *** this review,different designs related to angiogenesis are summarized by collecting the literature from recent *** 3D-printed scaffolds are classified into four major categories and discussed in detail,from elementary porous scaffolds to the most advanced bone-like ***,structural design suggestions to achieve rapid angiogenesis are proposed by analyzing the above *** review can provide a reference for organizations or individual academics to achieve improved bone defect repair and regeneration using 3D printing.

摘要：The multidisciplinary research field of bioprinting combines additive manufacturing,biology and material sciences to cre-ate bioconstructs with three-dimensional architectures mimicking natural living *** high interest in the possibility of reproducing biological tissues and organs is further boosted by the ever-increasing need for personalized medicine,thus allowing bioprinting to establish itself in the field of biomedical research,and attracting extensive research efforts from companies,universities,and research institutes *** this context,this paper proposes a scientometric analysis and critical review of the current literature and the industrial landscape of bioprinting to provide a clear overview of its fast-changing and complex *** scientific literature and patenting results for 2000-2020 are reviewed and critically analyzed by retrieving 9314 scientific papers and 309 international patents in order to draw a picture of the scientific and industrial landscape in terms of top research countries,institutions,journals,authors and topics,and identifying the technology hubs *** review paper thus offers a guide to researchers interested in this field or to those who simply want to under-stand the emerging trends in additive manufacturing and 3D bioprinting.

摘要：Three-dimensional(3D)tumor models prepared from patient-derived cells have been reported to imitate some of the biological development processes of in situ tumors in *** 3D tumor models share several important characteristics with their in vivo tumor ***,their applications in tumor modeling,drug screening,and precision-targeted treatment are ***,the establishment of tumormodels is subject to several challenges,including advancements in scale size,repeatability,structural precision in time and space,vascularization,and the tumor ***,bioprinting technologies enabling the editorial arrangement of cells,factors,and materials have improved the simulation of tumormodels in *** the 3D bioprinted tumor models,the organoidmodel has been widely appreciated for its advantages of maintaining high heterogeneity and capacity for simulating the developmental process of tumor *** this review,we outline approaches and potential prospects for tumor model bioprinting and discuss the existing bioprinting technologies and bioinks in tumor model *** multidisciplinary combination of tumor pathology,molecular biology,material science,and additive manufacturing will help overcome the barriers to tumor model construction by allowing consideration of the structural and functional characteristics of in vitro models and promoting the development of heterogeneous tumor precision therapies.