Yaxiong Liu

Xi'an Jiaotong University | XJTU · State Key Laboratory for Manufacturing Systems Engineering

A Ti/β-TCP composite porous scaffold with a hierarchical pore structure composed of 3D printed interconnected macroscopic pores and sintered microscopic pores was prepared by direct ink writing (DIW) 3D printing technology. This method can control the extrusion of composite ink at room temperature and produce a 3D scaffold using layer-by-layer depo...

Strong and tough β-TCP/PCL composite scaffolds with interconnected porosity were developed by combining digital light processing and vacuum infiltration. The composite scaffolds were comprised of pure β-TCP, β-TCP matrix composite and PCL matrix composite. The porous β-TCP/PCL composite scaffolds showed remarkable mechanical advantages compared wit...

Comprehensive mechanical properties (high strength, good fatigue resistance and tunable stiffness) are significant for large and load-bearing implants, but still remain a challenge in practical applications. Polyetheretherketone (PEEK)-Ti6Al4V interpenetrating phase composites (IPCs) with comprehensive mechanical properties were developed using a t...

Mask Projection Stereolithography (MPSL), due to its high printing resolution, is suitable for fabricating porous polymer architectures that are used as carbon scaffold precursors. In the present work, a carbon scaffold with a controllable small porous structure was fabricated by MPSL. A polymer lattice structure used as the carbon scaffold precurs...

Endothelial cells (ECs) dysfunction is an important predictor of and contributor to the pathobiology of cardiovascular diseases. However, most in vitro studies are performed using monolayer cultures of ECs on 2D tissue polystyrene plates (TCPs), which cannot reflect the physiological characteristics of cells in vivo. Here, we used 2D TCPs and a 3D...

Mask Projection Stereolithography (MPSL) is an additive manufacturing technology that allows direct fabrication of complex parts from liquid resin. However, the present MPSL systems cannot meet the requirements of high accuracy and large building envelope at the same time. In order to solve this problem, a Double Mask Projection Stereolithography (...

Reducing the viscosity of high solid-loading ceramic suspensions and controlling the resolution of ceramic green parts produced by digital light processing (DLP) 3D printing are two important concerns in the ceramic additive manufacturing industry. The presence of ceramic particles within a photopolymerizable system leads to light scattering that r...

This paper aims to study the endoprosthesis of a patient from the perspective of clearance between the hip bone and the implant. The implant was made with biocompatible titanium Ti-6Al-4V ELI through the additive manufacturing technique known as SLM. FEA was done in ABAQUS to study the stress distribution in the prosthesis with and without the clea...

Bioactive glass ceramics have excellent biocompatibility and osteoconductivity; and can form direct chemical bonds with human bones; thus, these ceramic are considered as "Smart" materials. In this study, we develop a new type of bioactive glass ceramic (AP40mod) as a scaffold containing Endothelial progenitor cells (EPCs) and Mesenchymal stem cell...

In this study, photosensitive resin mould was made by stereolithography technology to inject individualized polyether ether ketone (PEEK) parts. In simulation experiment, the temperature field of the PEEK injection mould was analysed by finite element analysis; it was preliminarily determined that the resin mould will not be deformed during the inj...

Background: Carotid artery geometry is important for recapitulating a pathophysiological microenvironment to study wall shear stress (WSS)-induced endothelial dysfunction in atherosclerosis. Endothelial cells (ECs) cultured with hydrogel have been shown to exhibit in vivo-like behaviours. However, to date, studies using hydrogel culture have not f...

Background: After magnetic compressive anastomosis, anastomat passage through the narrow channels of the digestive tract is difficult owing to the device's large volume. Such passage can lead to mechanical damage to the digestive tract or anastomat's unstable excretion time. This article presents a new magnetic compressive anastomotic approach. M...

Background: Magnetic compression anastomosis (MCA) is a commonly used anastomosis method. MCA was widely used in tissues repair, gastroenterostomy, choledochoenterostomy, and so on. It is safer and more effective than stapler and manual surgical suturing. However, there are few detailed studies on the biomechanical characteristics and tissue trans...

Tantalum has excellent biocompatibility and mechanical properties that can be used as an ideal bone scaffold material. However, its applications have been limited because of its high melting point, affinity to oxygen and cost. In this study, we used an inexpensive tantalum oxide powder as a starting material and developed a method combining gel cas...

To address issues such as transportation and the time-consuming nature of tissue-engineered liver for use as an effective drug metabolism and toxicity testing model, "ready-to-use" cryogenic tissue-engineered liver needs to be studied. The research developed a cryogenic tissue-engineered liver slice (TELS), which comprised of HepG2 cells and calciu...

Custom-made pelvic prostheses are normally employed to reconstruct the biomechanics of the pelvis for improving patient’s life quality. However, due to the large demand of biomechanical performance around the pelvic system, the customized prosthesis needs to be studied for its strength and stability. A hemi-pelvic finite element model, including a...

Most of the existing tissue-engineered scaffolds for the regeneration of anterior cruciate ligament (ACL) are unable to recapitulate the structural/compositional/mechanical gradients at native ACL-bone interface. Here we present a unique electrospinning strategy to fabricate microfiber-reinforced nanofibrous scaffolds with structure and composition...

The aim of this study was to design a hemi-pelvic prosthesis for a patient affected by pelvic sarcoma. To investigate the biomechanical functionality of the pelvis reconstructed with designed custom-made prosthesis, a patient-specific finite element model of whole pelvis with primary ligaments inclusive was constructed based on the computed tomogra...

Over the past few decades, there has been an increasing interest in the fabrication of complex high-resolution three-dimensional (3D) architectures at micro/nanoscale. These architectures can be obtained through conventional microfabrication methods including photolithography, electron-beam lithography, femtosecond laser lithography, nanoimprint li...

Particle size gradation is regarded as an effective method for overcoming the contradicting requirements in three-dimensional printing (3DP). In present work, particle size gradation was optimized to obtain both acceptable flowability of powder material and high-strength 3D-printed glass-ceramic products. The effect of gradation on the printing pro...

Asphericity and out-of-roundness are generally used to evaluate the manufacturing quality of ultra-high molecular weight polyethylene (UHMWPE) cup inner surfaces, which can potentially affect initial clinical wear and contribute to osteolysis of total hip arthroplasty. This study measured the location and magnitude of asphericity and the out-of-rou...

Electrohydrodynamic printing has gained increasing attentions to fabricate micro/nanoscale patterns in a controlled and cost-effective manner. However, most of the existing studies focus on printing tiny dried fibres, which limits its applications in high-resolution cell printing. Here we investigated the feasibility of using electrohydrodynamic pr...

It is challenging for the existing three-dimensional (3D) printing techniques to fabricate high-resolution 3D microstructures with low costs and high efficiency. In this work we present a solvent-based electrohydrodynamic 3D printing technique that allows fabrication of microscale structures like single walls, crossed walls, lattice and concentric...

Bioprinting is one of several newly emerged tissue engineering strategies that hold great promise in alleviating of organ shortage crisis. To date, a range of living biological constructs have already been fabricated in vitro using this technology. However, an in vitro approach may have several intrinsic limitations regarding its clinical applicabi...

Conventional ligament grafts with single material composition cannot effectively integrate with the host bones due to mismatched properties and eventually affect their long-term function in vivo. Here we presented a multi-material strategy to design and fabricate composite scaffolds including ligament, interface and bone multiphased regions. The in...

Mal-rotation of the components in total knee arthorplasty (TKA) is a major cause of postoperative complications, with an increased propensity for implant loosening or wear leading to revision. A musculoskeletal multi-body dynamics model was used to perform a parametric study of the effects of the rotational mal-alignments in TKA on the knee loading...

A maskless electrohydrodynamic direct-writing lithographic strategy was presented to flexibly fabricate user-specific micropatterns on silicon substrates. By optimizing the operating parameters, parallel lines as well as lattices with line width of about 2 μm could be stably deposited. The printed micropatterns were found to function as sacrificial...

To summarize the recent development of the magnetic compression anastomosis in surgery. The abroad and domestic relevant literature about magnetic compression anastomosis was extensively reviewed, and comprehensive analyzed. Magnetic compression anastomosis in the reconstruction of the body lumen is a simple and effective way; laparoscopy combined...

To review the current research status of in situ three-dimensional (3-D) printing technique and future trends. Recent related literature about in situ 3-D printing technique was summarized, reviewed, and analyzed. Based on the clinical need for surgical repair, in situ 3-D printing technique is in the preliminary study, mainly focuses on in situ de...

Lower extremity musculoskeletal (MSK) computational models play an important role in predicting joint forces and muscle activation simultaneously and are valuable for investigating functional outcomes of the implants. However, current computational MSK models of total knee replacement (TKR) rarely consider the bearing surface geometry of the implan...

There is a growing interest in non-surgical gait rehabilitation treatments to reduce the loading in the knee joint. In particular, synergetic kinematic changes required for joint offloading should be determined individually for each subject. Previous studies for gait rehabilitation designs are typically relied on a “trial-and-error” approach, using...

Bottom-up tissue engineering provides a promising way to recreate complex structural organizations of native organs in artificial constructs by assembling functional repeating modules. However, it is challenging for current bottom-up strategies to simultaneously produce a controllable and immediately perfusable microfluidic network in modularly ass...

Lower extremity musculoskeletal computational models play an important role in predicting joint forces and muscle activation simultaneously and are valuable for investigating functional outcomes of the implants. However, current computational musculoskeletal models of total knee replacement rarely consider the bearing surface geometry of the implan...

Objective: To construct large block of engineered liver tissue by co-culture of fibroblasts and hepatocytes on collagen hydrogels in vitro and do in vivo implantation research. Methods: Silastic mould was prepared using three-dimensional printing technology. The collagen hydrogel scaffold was prepared by collagen hydrogel gel in the silicone mou...

Objective: To summarize the latest research development of the application of digital design and three-dimensional (3-D) printing technique on individualized medical treatment. Methods: Recent research data and clinical literature about the application of digital design and 3-D printing technique on individualized medical treatment in Xi'an Jiao...

Objective: To solve the fixation problem between ligament grafts and host bones in ligament reconstruction surgery by using ligament-bone composite scaffolds to repair the ligaments, to explore the fabrication method for ligament-bone composite scaffolds based on three-dimensional (3-D) printing technique, and to investigate their mechanical and b...

Objective: To investigate whether subchondral bone microstructural parameters are related to cartilage repair during large osteochondral defect repairing based on three-dimensional (3-D) printing technique. Methods: Biomimetic biphasic osteochondral composite scaffolds were fabricated by using 3-D printing technique. The right trochlea critical...

A new system of blood flow block for control of bleeding in abdominal operation is composed of an abdominal magnetic blocking unit, an abdominal external electromagnet unit and other non-magnetic operation instrument. The abdominal external electromagnetic unit is placed in advance in the operation bed. The abdominal magnetic blocking unit can be p...

The fabrication of vascularized parenchymal organs to alleviate donor shortage in organ transplantation is the holy grail of tissue engineering. However, conventional tissue-engineering strategies have encountered huge challenges in recapitulating complex structural organization of native organs (e.g., orderly arrangement of multiple cell types and...

Microfluidic networks are extensively used in miniaturized lab-on-a-chip systems. However, most of the existing microchannels are simply designed and the corresponding microfluidic systems commonly require external pumps to achieve effective fluid transport. Here we employed microfabrication techniques to replicate naturally-optimized leaf venation...

A microreplication method is presented to transfer nature optimized vascular network of leaf venation into various synthetic matrixes. The biomaterial hydrogel with these microfluidic networks is proven to facilitate the growth of endothelial cells and simultaneously function as convection pathways to transport nutrients and oxygen in a pump-free b...

A three-dimensional (3D) microfluidic network plays an important role in engineering thick organs. However, most of the existing methods are limited to mechanically robust synthetic biomaterials and only planar or simple microfluidic networks have been incorporated into soft natural biopolymers. Here we presented an automatic layer-by-layer micromo...

Biomaterial scaffolds play an important role in maintaining the viability and biological functions of highly metabolic hepatocytes in liver tissue engineering. One of the major challenges involves building a complex microchannel network inside three-dimensional (3D) scaffolds for efficient mass transportation. Here we presented a biomimetic strateg...

Microfluidic scaffold or hydrogel has attracted extensive interests in generating thick tissues or organs. It is still challenging to produce complex three-dimensional (3D) microfluidic network from natural biomaterials like silk fibroin and chitosan. Here we present a bottom-up approach to fabricate 3D microfluidic constructs by rolling monolayer...

Silk fibroin has shown great potential for tissue engineering applications. However, it is still challenging to generate three-dimensional (3D) silk fibroin microfluidic scaffolds with desirable properties. Here we proposed to improve the structural and biological properties of silk fibroin scaffolds by the addition of gelatin. The blending ratio o...

Cell cultures for tissue engineering are traditionally prepared on two-dimensional or three-dimensional scaffolds with simple pores; however, this limits mass transportation, which is necessary for cell viability and function. In this paper, an innovative method is proposed for fabricating porous scaffolds with designed complex micro-architectures....

Scaffold-based tissue engineering has made great progress in fabricating relatively simple tissues. One of the major challenges in creating thick complex organs is to achieve sufficient nutrient supply as well as uniform cell distribution in a three-dimensional (3D) scaffold. Here we employed microstructured ice templates to fabricate silk fibroin-...

For improving the theory of gradient microstructure of cartilage/bone interface, human distal femurs were studied. Scanning Electron Microscope (SEM), histological sections and MicroCT were used to observe, measure and model the microstructure of cartilage/bone interface. The results showed that the cartilage/bone interface is in a hierarchical str...

This paper presents a novel bio-microelectrode structure for deep-brain stimulation in neural disorder treatment and a method for connecting PtIr10 microwires onto this microelectrode. The microelectrode is consisted of four stimulation sites fabricated by microfabrication process and two recording sites formed by encapsulation technique. After Si-...

Purpose This paper aims to describe computer‐aided design and rapid prototyping (RP) systems for the preoperative planning and fabrication of custom‐made implant. Design/methodology/approach A patient with mandible defect underwent reconstruction using custom‐made implant. 3D models of the patient's skull are generated based on computed tomography...

Hydrodynamic cellular environment plays an important role in translating engineered tissue constructs into clinically useful grafts. However, the cellular fluid dynamic environment inside bioreactor systems is highly complex and it is normally impractical to experimentally characterize the local flow patterns at the cellular scale. Computational fl...

A porous chitosan-gelatin scaffold with specific geometry and complex internal microarchitectures was fabricated via a novel indirect rapid prototyping technique. A stereolithography (SL) technique was employed to build the resin mold, based on which a high-resolution poly-dimethylsilicone (PDMS) mold was microreplicated. The chitosan-gelatin hybri...

Three dimensional (3D) channel networks are the key to promise the uniform distribution of nutrients inside 3D hepatic tissue engineering scaffolds and prompt elimination of metabolic products out of the scaffolds. 3D chitosan/gelatin porous scaffolds with predefined internal channels were fabricated and a combination of light microscope, laser con...

The reconstruction of maxillofacial bone defects by the intraoperative modeling of implants may reduce the predictability of the esthetic result, leading to more invasive surgery and increased surgical time. To improve the maxillofacial surgery outcome, modern manufacturing methods such as rapid prototyping (RP) technology and methods based on reve...

The purpose of this study was to investigate the effect of latency on the development of bone lengthening force and bone mineralization during mandible distraction osteogenesis. Distraction tensions were investigated at different latency period in 36 rabbits using internal unilateral distractor. Strain gauges were prepared and attached to the distr...