Engineering Highly Aligned and Densely Populated Cardiac Muscle Bundles via Fibrin Remodeling in 3D-Printed Anisotropic Microfibrous Lattices.

Replicating the structural and functional features of native myocardium, particularly its high-density cellular alignment and efficient electrical connectivity, is essential for engineering functional cardiac tissues. Here, novel electrohydrodynamically printed InterPore microfibrous lattices with anisotropic architectures are introduced to promote high-density cellular alignment and enhanced tissue interconnectivity. The interconnected pores in the microfibrous lattice enable dynamic, cell-mediated remodeling of fibrous hydrogels, resulting in continuous, mechanically stable tissue bundles.

Multi-material Electrohydrodynamic Printing of Bioelectronics with Sub-Microscale 3D Gold Pillars for In Vitro Extra- and Intra-Cellular Electrophysiological Recordings.

Micro/nanoscale 3D bioelectrodes gain increasing interest for electrophysiological recording of electroactive cells. Although 3D printing has shown promise to flexibly fabricate 3D bioelectronics compared with conventional microfabrication, relatively-low resolution limits the printed bioelectrode for high-quality signal monitoring. Here, a novel multi-material electrohydrodynamic printing (EHDP) strategy is proposed to fabricate bioelectronics with sub-microscale 3D gold pillars for in vitro electrophysiological recordings.

Mechanical behaviour of additive manufactured PEEK/HA porous structure for orthopaedic implants: Materials, structures and manufacturing processes.

Polyether-ether-ketone (PEEK) composites represent one of the most promising approaches to overcoming the weak osseointegration associated with the bioinertness of PEEK, making them highly suitable for clinical translation. Implants with porous structures fabricated by additive manufacturing offer the potential for long-term stability by promoting bone ingrowth. However, despite the importance of porous design, there is still no consensus on the optimal approach for PEEK-based composites.

3D printing of drug delivery systems enhanced with micro/nano-technology.

Drug delivery systems (DDSs) are increasingly important in ensuring drug safety and enhancing therapeutic efficacy. Micro/nano-technology has been utilized to develop DDSs for achieving high stability, bioavailability, and drug efficiency, as well as targeted delivery; meanwhile, 3D printing technology has made it possible to tailor DDSs with diverse components and intricate structures. This review presents the latest research progress integrating 3D printing technology and micro/nano-technology for developing novel DDSs.

Equal-Additive-Subtractive Remanufacturing Integrated Laser Directed Energy Deposition with Shot Peening and Machining Induced High Performance of Plunger Rod.

The number of easily destroyed parts with high value is increasing in industry, and green remanufacture engineering is now mainstream in this new and expanding industrial field. Equal-additive-subtractive manufacturing, as a new technology that combines strengthening technology, additive manufacturing, and machining technology has great potential for development in the area of remanufacturing. Aiming at the damage characteristics of a plunger rod, this paper carries out a study about the repair technology by equal-additive-subtractive manufacturing of laser-directed energy deposition and shot peening.

Biomimetic design and integrated biofabrication of an in-vitro three-dimensional multi-scale multilayer cortical model.

The lack of accurate and reliable brain models hinders the development of brain science and research on brain diseases. Owing to the complex structure of the brain tissue and its highly nonlinear characteristics, the construction of brain-like tissue models remains one of the most challenging research fields in the construction of living tissues. This study proposes a multi-scale design of a brain-like model with a biomimetic cortical structure, which includes the macroscopic structural features of six layers of different cellular components, as well as micrometer-scale continuous fiber structures running through all layers vertically.

Multimaterial Printing of Serpentine Microarchitectures with Synergistic Mechanical/Piezoelectric Stimulation for Enhanced Cardiac-Specific Functional Regeneration.

Recreating the natural heart's mechanical and electrical environment is crucial for engineering functional cardiac tissue and repairing infarcted myocardium in vivo. In this study, multimaterial-printed serpentine microarchitectures are presented with synergistic mechanical/piezoelectric stimulation, incorporating polycaprolactone (PCL) microfibers for mechanical support, polyvinylidene fluoride (PVDF) microfibers for piezoelectric stimulation, and magnetic PCL/FeO for controlled deformation via an external magnet. Rat cardiomyocytes in piezoelectric constructs, subjected to dynamic mechanical stimulation, exhibit advanced maturation, featuring superior sarcomeric structures, improved calcium transients, and upregulated maturation genes compared to non-piezoelectric constructs.

Consecutive multimaterial printing of biomimetic ionic hydrogel power sources with high flexibility and stretchability.

Electric eel is an excellent example to harness ion-concentration gradients for sustainable power generation. However, current strategies to create electric-eel-inspired power sources commonly involve manual stacking of multiple salinity-gradient power source units, resulting in low efficiency, unstable contact, and poor flexibility. Here we propose a consecutive multimaterial printing strategy to efficiently fabricate biomimetic ionic hydrogel power sources with a maximum stretchability of 137%.

[Development and Challenges of Additive Manufactured Customized Implant].

Additive manufacturing (3D printing) technology aligns with the direction of precision and customization in future medicine, presenting a significant opportunity for innovative development in high-end medical devices. Currently, research and industrialization of 3D printed medical devices mainly focus on nondegradable implants and degradable implants. Primary areas including metallic orthopaedic implants, polyether-ether-ketone (PEEK) bone implants, and biodegradable implants have been developed for clinical and industrial application.

Biotribological properties of 3D printed high-oriented short carbon fiber reinforced polymer composites for artificial joints.

Short carbon fiber (SCF) reinforced polymer composites are expected to possess outstanding biotribological and mechanical properties in certain direction, while the non-oriented SCF weakens its reinforcing effect in the matrix. In this work, high-oriented SCF was achieved during nozzle extrusion, and then SCF reinforced polyether-ether-ketone (PEEK) composites were fabricated by fused deposition modeling (FDM). The concrete orientation process of SCF was theoretically simulated, and significant shear stress difference was generated at both ends of SCF.

Microphysiological systems inspired by leaf venation.

Nature-inspired microfluidic networks are revolutionizing microphysiological systems, allowing for the precise emulation of human physiology. This article delves into the fabrication techniques of leaf-venation-inspired (LVI) microfluidic networks and explores their transformative applications in organ-on-a-chip and tissue engineering, showcasing their pivotal role in advancing biomedical research.

Outcomes following the excision of sarcoma and chest wall reconstruction using 3D printed implant.

The survival outcomes of patients with chest wall sarcomas (CWS) were evaluated after receiving wide excision and chest wall reconstruction by using three-dimensional printed (3DP) implants. The survival outcomes evaluating the effect of 3DP implants for chest wall reconstruction is lacking. Here, forty-nine patients with CWS underwent radical wide excision and chest wall reconstruction using 3DP implants.

Heart-on-a-chip systems with tissue-specific functionalities for physiological, pathological, and pharmacological studies.

Recent advances in heart-on-a-chip systems hold great promise to facilitate cardiac physiological, pathological, and pharmacological studies. This review focuses on the development of heart-on-a-chip systems with tissue-specific functionalities. For one thing, the strategies for developing cardiac microtissues on heart-on-a-chip systems that closely mimic the structures and behaviors of the native heart are analyzed, including the imitation of cardiac structural and functional characteristics.

Mechanical Metamaterials for Handwritten Digits Recognition.

The increasing needs for new types of computing lie in the requirements in harsh environments. In this study, the successful development of a non-electrical neural network is presented that functions based on mechanical computing. By overcoming the challenges of low mechanical signal transmission efficiency and intricate layout design methodologies, a mechanical neural network based on bistable kirigami-based mechanical metamaterials have designed.

Microstructure Optimization for Design of Porous Tantalum Scaffolds Based on Mechanical Properties and Permeability.

Porous tantalum (Ta) implants have important clinical application prospects due to their appropriate elastic modulus, and their excellent bone growth and bone conduction ability. However, porous Ta microstructure designs generally mimic titanium (Ti) implants commonly used in the clinic, and there is a lack of research on the influence of the microstructure on the mechanical properties and penetration characteristics, which will greatly affect bone integration performance. This study explored the effects of different microstructure parameters, including the fillet radius of the middle plane and top planes, on the mechanics and permeability properties of porous Ta diamond cells through simulation, and put forward an optimization design with a 0.

Coaxial Electrohydrodynamic Printing of Microscale Core-Shell Conductive Features for Integrated Fabrication of Flexible Transparent Electronics.

Reliable insulation of microscale conductive features is required to fabricate functional multilayer circuits or flexible electronics for providing specific physical/chemical/electrical protection. However, the existing strategies commonly rely on manual assembling processes or multiple microfabrication processes, which is time-consuming and a great challenge for the fabrication of flexible transparent electronics with microscale features and ultrathin thickness. Here, we present a novel coaxial electrohydrodynamic (CEHD) printing strategy for the one-step fabrication of microscale flexible electronics with conductive materials at the core and insulating material at the outer layer.

Spatial 3D Printing of Continuous Fiber-Reinforced Composite Multilayer Truss Structures with Controllable Structural Performance.

Continuous fiber-reinforced composite truss structures have broad application prospects in aerospace engineering owing to their high structural bearing efficiency and multifunctional applications. This paper presents the design and fabrication of multilayer truss structures with controlled mechanical properties based on continuous fiber-reinforced thermoplastic composite 3D printing. Continuous fiber composite pyramid trusses fabricated by 3D printing have high specific stiffness and strength, with maximum equivalent compression modulus and strength of 401.

Impact Resistance of 3D-Printed Continuous Hybrid Fiber-Reinforced Composites.

Improving the resilience of 3D-printed composites through material extrusion technology (MEX) is an ongoing challenge in order to meet the rigorous requirements of critical applications. The primary objective of this research was to enhance the impact resistance of 3D-printed composites by incorporating continuous hybrid fibers. Herein, continuous virgin carbon (1k) and Kevlar (130D and 200D) fibers were used with different weight and volume fractions as reinforcing fibers to produce hybrid and non-hybrid composites for impact resistance testing to obtain energy absorption with different impact energies: 20 J, 30 J, 40 J, and 50 J.

Advancing Intelligent Organ-on-a-Chip Systems with Comprehensive In Situ Bioanalysis.

In vitro models are essential to a broad range of biomedical research, such as pathological studies, drug development, and personalized medicine. As a potentially transformative paradigm for 3D in vitro models, organ-on-a-chip (OOC) technology has been extensively developed to recapitulate sophisticated architectures and dynamic microenvironments of human organs by applying the principles of life sciences and leveraging micro- and nanoscale engineering capabilities. A pivotal function of OOC devices is to support multifaceted and timely characterization of cultured cells and their microenvironments.

Pore size-mediated macrophage M1 to M2 transition affects osseointegration of 3D-printed PEEK scaffolds.

Increasing evidence indicates that macrophages play an important role in angiogenesis and bone regeneration. Because the phenotypic polarization of macrophage is extremely sensitive to the pore size of materials, poly(ether-ether-ketone) (PEEK) scaffolds with pore sizes of 0, 200, and 400 μm were prepared, and the influence of pore size-mediated macrophage polarization on subsequent angiogenesis and osteogenesis was examined. The interaction results of macrophages and scaffolds indicated that macrophages were responsive to the pore size of three-dimensional (3D)-printed PEEK scaffolds, and large pore size scaffolds showed greater potential in inducing M1 to M2 transition of macrophage and enhanced macrophage secretion of high concentrations of osteogenesis-related and angiogenesis-related cytokines.

Programmable spatial deformation by controllable off-center freestanding 4D printing of continuous fiber reinforced liquid crystal elastomer composites.

Owing to their high deformation ability, 4D printed structures have various applications in origami structures, soft robotics and deployable mechanisms. As a material with programmable molecular chain orientation, liquid crystal elastomer is expected to produce the freestanding, bearable and deformable three-dimensional structure. However, majority of the existing 4D printing methods for liquid crystal elastomers can only fabricate planar structures, which limits their deformation designability and bearing capacity.

Biomimetic three-dimensional glioma model printed for the studies of glioma cells and neurons interactions.

1The interactions between glioma cells and neurons are important for glioma progression but are rarely mimicked and recapitulated in three-dimensional (3D) models, which may affect the success rate of relevant drug research and development. In this study, an bioprinted 3D glioma model consisting of an outer hemispherical shell with neurons and an inner hemisphere with glioma cells is proposed to simulate the natural glioma. This model was produced by extrusion-based 3D bioprinting technology.

3D Bioprinting of Neurovascular Tissue Modeling with Collagen-Based Low-Viscosity Composites.

In vitro neurovascular unit (NVU) models are valuable for investigating brain functions and developing drugs. However, it remains challenging to recapitulate the native architectural features and ultra-soft extracellular matrix (ECM) properties of the natural NVU. Cell-laden bioprinting is promising to prepare complex living tissues, but hard to balance the fidelity and cell growth.

Development of Electro-Conductive Composite Bioinks for Electrohydrodynamic Bioprinting with Microscale Resolution.

Bioprinting has attracted extensive attention in the field of tissue engineering due to its unique capability in constructing biomimetic tissue constructs in a highly controlled manner. However, it is still challenging to reproduce the physical and structural properties of native electroactive tissues due to the poor electroconductivity of current bioink systems as well as the limited printing resolution of conventional bioprinting techniques. In this work, an electro-conductive hydrogel is prepared by introducing poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) into an RGD (GGGGRGDSP)-functionalized alginate and fibrin system (RAF), and then electrohydrodynamic (EHD)-bioprinted to form living tissue constructs with microscale resolution.