Constructing composite tissues or organs with structural integrity remains a formidable challenge, nonetheless. Stem cells and the periosteum are essential for bone regeneration, and co-culture engineering has demonstrated its capacity to repair bone defects successfully. Co-culture bioprinting was strategically proposed, complemented by the design of a tissue-engineered biphasic bone-periosteum complex. The bone phase's supporting scaffold was composed of poly-L-lactic acid/hydroxyapatite (PLLA/HA). Gelatin methacryl (GelMA) was used to encapsulate rabbit bone mesenchymal stem cells (BMSCs) and periosteum-derived stem cells (PDSCs) to model the extracellular matrix of bone and periosteum, respectively, establishing a co-culture layer connecting the two tissue phases. Through the strategic modulation of PLLA/HA material ratios and GelMA crosslinking time, a complex with substantial mechanical resilience and cellular activity was developed and then implanted into the rabbit skull's deficient region. In the quantitative assessment of imaging and histology, the bone-periosteum biphasic complex group displayed a significantly greater improvement in bone repair compared to other control groups, illustrating this complex's benefit to both bone regeneration and repair. The co-culture bioprinting method for engineered tissue fabrication is exceptionally promising, and its application to more complex tissues and solid organs for tissue regeneration and transplantation is anticipated.Damage to neural tissue is a prominent feature of spinal cord injury (SCI), which causes severe motor and sensory deficits. Considering the restricted capacity for self-repair in damaged spinal cord tissue, diverse therapeutic methods, such as cell-based therapies, pharmaceutical interventions, and the implantation of tissue-engineering scaffold materials, have been used to address spinal cord injuries. Yet, each of these approaches proves inadequate in achieving the hoped-for results, due to their respective constraints. Advanced tissue engineering scaffolds, with their tailored topographical features, suitable composition, and sustained drug release properties, can be used to recruit endogenous neural stem cells (NSCs), induce neuronal differentiation pathways, and promote neuron maturation compared to other techniques. The process of spinal cord tissue regeneration can lead to the regaining of motor function capabilities. This study reports the fabrication of oxymatrine (OMT)-containing spinal cord extracellular matrix hydrogel scaffolds, which were reinforced with fiber bundles, through near-field direct write electrospinning. OMT was subsequently applied as a coating to the spinal cord extracellular matrix-based hydrogel. The in vitro degradation behavior and the physical/chemical properties of the composite scaffolds were investigated. The in vitro differentiation of neural stem cells (NSCs) into neurons was promoted and into astrocytes inhibited by composite scaffolds loaded with OMT, as shown in cell culture experiments. In vivo studies revealed that OMT-loaded composite scaffolds recruited neural stem cells (NSCs) from the host tissue, fostering neuronal differentiation and axonal outgrowth at the injury site, while simultaneously hindering glial scar formation at and around the lesion site. This resulted in enhanced motor function recovery in rats suffering from spinal cord injury (SCI). In conclusion, the application of 3D-printed microfiber-reinforced spinal cord extracellular matrix hydrogel scaffolds, loaded with OMT, presents a potential therapeutic strategy for spinal cord injury.In this investigation, a posterior lumbar interbody fusion cage for osteoporosis patients was both designed and produced using the 3D printing process. The cage's structure, shaped to conform to the anatomical endplate's curved surface, enables stress transmission, while its internal lattice design is essential for bone growth. The curved surface (CS-type) cage design incorporated statistical results from osteoporosis patient endplate morphology, leveraging finite element (FE) analysis and weight topology optimization under different lumbar spine activity levels. Different daily activities were simulated to assess the distinct biomechanical behaviors of CS-type and P-type cages through non-linear finite element analysis. The internal cavity of the CS-type cage subsequently housed a gyroid lattice, specified with a spiral wall thickness of 0.25. The CS-cage's fabrication using metal 3D printing allowed for the execution of in vitro biomechanical testing procedures. Analysis of the finite element model showed that, for the P-type cage implantation, stress levels at the inferior L3 and superior L4 endplates were greater under all daily activities than those of the CS-type cage. Fractures in the P-type cage could arise from excessive stresses in the endplates, surpassing the material's ultimate strength (around 10 MPa) under combined loads of flexion, torsion, and bending. Under all load scenarios, the yield load, stiffness, and performance of our engineered CS-type cage satisfy the optional acceptance criteria defined in the ISO 23089 standard. A posterior lumbar interbody fusion cage, specifically designed with an osteoporosis-anatomical curved surface and internal lattice structure, was approved in this study. The design aims to achieve adequate structural integrity, improved stress transfer between the endplate and cage, and biomechanical strength that meets the standards required for commercially available cages.Collagen's inherent abundance in human tissues, coupled with its exceptional biocompatibility and low immunogenicity, makes it a cornerstone protein in both tissue engineering and the innovative technology of 3D bioprinting. However, it presents critical obstacles, encompassing complex and constrained extraction methods, commonly demonstrating batch-to-batch variations and the influence of variables, like temperature, pH, and ionic strength. We evaluated the applicability and effectiveness of a novel, fibrillar type I collagen as a standardized and reproducible material for the purposes of 3D printing and bioprinting. Exceptional performance was observed during the 3D printing of 5% w/w acidic, native fibrous collagen, allowing for the production of constructs up to 27 layers without collapse. Conversely, the fibrous collagen matrix has undergone modification to facilitate a swift, dependable, and readily neutralized procedure. TRIS-HCl neutralization enabled cellular inclusion without jeopardizing the printability. The cell-laden constructs were fabricated via pneumatic 3D printing under mild pressure (50-80 kPa), ensuring exceptional cellular viability (over 90%) and a stable substrate for in vitro cell growth and proliferation. Therefore, the investigated native type I collagen masses in this research are a reliable and reproducible source of collagen for the tasks of 3D printing and bioprinting.This work employed 3D printing to produce a polylactic acid (PLA) amniotic fornical ring (AFR) for the purpose of ocular surface reconstruction. This study retrospectively and interventionally analyzed patients with ocular surface diseases who received either personalized 3D-printed AFR-assisted amniotic membrane transplants (AMT) or traditional sutured amniotic membrane transplants (SAMT). Patient characteristics, treatment regimens, surgical times, epithelial healing durations, retention times, eye-sight variations, complications, and economic factors were evaluated in this study. Thirty-one patients (40 eyes) were incorporated into the 3D-printed AFR group, whereas the SAMT group received 19 patients (22 eyes). Clinical manifestations of AFR and SAMT overlapped significantly, featuring corneal and/or conjunctival epithelial deficiencies caused by chemical burns, thermal burns, Stevens-Johnson syndrome (SJS), or toxic epidermal necrolysis (TEN). The mean dissolution times for the AFR and SAMT groups were 15.11 days and 14.7 days, respectively. The AFR group's corneal healing reached 9091% (a range of 6610%-10000%), while the SAMT group's healed corneal area percentage was 9367% (a range of 6023%-10000%). In the AFR group, corneal epithelial healing took a median of 14 days (range 7-75), whereas the suture AMT group exhibited a median healing time of 30 days (range 14-55). There were no prominent distinctions in initial visual clarity, final visual clarity, or enhancement of visual clarity between the two cohorts. Operation duration in the SAMT group was considerably longer than the operation duration in the AFR group. Based on the cost analysis, the average expense per eye in the AFR group was substantially lower than the corresponding figure for the SAMT group. In addition, the 3D-printed and sterile AFRs demonstrated no significant eye-related side effects. Our research suggested the applicability of 3D-printed PLA scaffolds as an AFR device for issues relating to the ocular surface. Personalized 3D-printed AFR exhibits a more extended operational time and greater financial efficiency than conventional AMT, thereby easing the financial pressures on the healthcare system.For cable-driven soft robotic hands and grippers, compliant flexure joints have become a prevalent choice, ensuring safe encounters with humans and objects. A study in this paper describes a soft and compliant revolute flexure joint design, specifically using auxetic cellular mechanical metamaterials with a heterogeneous structure. enzyme inhibitors In comparison to conventional flexure joints, the proposed metamaterial flexure joint (MFJ), with its heterogeneous architecture inspired by human finger joints, allows for a large range of bending angles and mechanically tunable multi-stiffness bending motion. Control over the multi-level variation of joint stiffness, over the range of bending motion, is possible through adjusting the geometrical parameters of the cellular mechanical metamaterial unit cells. 3D printing was used to create the proposed flexure joints, using a standard benchtop printer and a single monolithic piece of flexible material. Grasping thin, deformable objects like wires and cables in robotic in-hand manipulation clearly demonstrates the utility of the MFJ.