Using artificial biomaterials in bone regenerative medicine for highly efficient osteoconduction into the bone defect to decrease the bone healing time is still a challenge. In this research, magnesium (Mg)-doped wollastonite (∼10% Mg was substituted for calcium (Ca) in β-CaSiO₃) (CSi-Mg10) bioceramic scaffolds with ultrahigh mechanical strength were fabricated using ceramic ink writing three dimensional (3D) printing. To evaluate the potential of other additives on the new bone regeneration efficiency, β-tricalcium phosphate (β-TCP) was introduced to the CSi-Mg10 ceramic ink at a concentration of 15% and the biphasic bioceramic scaffolds (CSi-Mg10/TCP15) were also fabricated using 3D printing. The mechanical characterization indicated that introduction of β-TCP led to nearly 50% mechanical decay, although the effect of the two heating schedules (one- and two-step sintering) on the compressive and flexural strengths of the scaffolds was significantly different. The bone regeneration results in critical sized calvarial defect of rabbits showed that the CSi-Mg10/TCP15 scaffolds displayed a markedly higher osteogenic capability than those on the CSi-Mg10 and β-TCP scaffolds after eight weeks, and reached ∼35% new bone tissue regeneration at 12 weeks postoperatively. These findings demonstrate that the CSi-Mg10/TCP15 bioceramic scaffolds can be well suited for stimulating in situ bone regeneration and for use in tissue engineering applications.

Hydroxyapatite (HA) bioceramics have garnered considerable attention owing to their applications in the field of bone repair and excellent biocompatibility. Compared to extrusion-based 3D printing, projection-based 3D printing (3DPP) can fabricate parts with complex geometry, high accuracy, and efficiency, which is very promising for bioceramic scaffolds. However, conventional 3DPP using a paste with low viscosity will cause severe shrinkage of the parts after sintering, which makes it unsuitable for bioceramic scaffolds, and a system investigation of the printing process remains insufficient. In this study, we proposed a 3DPP device suitable for bioceramic scaffolds and investigated the additive manufacturing of HA scaffolds. Ceramic paste properties and process parameters of curing, debinding, and sintering were initially examined. The mechanical properties, shrinkage, and biocompatibility in vitro of the sintered samples were further investigated. The obtained results indicate that HA bioceramics with uniform morphology, complex structure, and high accuracy can be manufactured using the 3DPP equipment. HA scaffolds have the mechanical strength of human cancellous bone, while HA scaffolds cultured with osteoblast precursor cells possess strong biocompatibility and can promote osteoblast adhesion, proliferation, and differentiation. These results suggest a promising application of the 3DPP technique in the preparation of bioceramic scaffolds, and the HA scaffolds fabricated using the 3DPP technique exhibit promising potential in fulfilling a constructive role in the biomedical field of human bone regeneration repair.

This paper is based on the “Fast Pneumatic Mesh Driver” (FPN) used to couple a silicone rubber soft body with a rigid skeleton. A rigid-flexible coupling soft-body human-like finger design scheme is proposed to solve the problem of low load on the soft-body gripping hand. The second-order Yeoh model is used to establish the statics model of the soft humanoid finger, and the ABAQUS simulation analysis software is used for correction and comparison to verify the feasibility of the soft humanoid finger bending. The thickness of the driver cavity and the confining strain layer were determined by finite element simulation. The mold casting process is used to complete the preparation of human-like fingers and design a pneumatic control system for experiments combined with 3D printing technology. The experimental results show that the proposed rigid-flexible coupling soft body imitating the human finger structure can realize the corresponding actions, such as the multi-joint bending and side swinging, of human fingers. Compared with the traditional pure soft-body finger, the fingertip output force is significantly improved. The optimal design and simulation analysis of the human gripper and the feasibility of the application have practical guiding significance.

Due to the increasing cases of bone damage and bone graft demand, bone-repair technology has great social and economic benefits and the manufacturing of artificial bone implants has become a focus in the domain of regenerative therapy. Considering that the traditional manufacturing process cannot effectively control the overall size of the scaffold, the diameter and shape of micropores, and the interoperability of micropores, 3D printing technology has emerged as a focal point of research within the realm of bone tissue engineering. However, the printing accuracy of extrusion-based biological 3D printing techniques is low. In this research, we utilized three-dimensional printing technology to develop high-precision magnesium-containing silicate (CSi-Mg) scaffolds. The precision of this innovative method was scrutinized and the influence of pore size on scaffold strength was systematically analyzed. Furthermore, the influence of the pore architecture on the sidewalls of these 3D-printed scaffolds was evaluated in terms of mechanical properties. The CSi-Mg scaffold, post a 3-week immersion in a simulated body of fluid, demonstrated a high modulus of elasticity (exceeding 404 MPa) and significant compressive strength (beyond 47 MPa). Furthermore, it exhibited commendable bioactivity and biodegradability. These results suggest that the high-precision 3D-printed CSi-Mg scaffolds hold great promise for addressing challenging bone defect cases.

Hydrogel microspheres are widely used in tissue engineering, such as 3D cell culture and injection therapy, and among which, heterogeneous microspheres are drawing much attention as a promising tool to carry multiple cell types in separated phases. However, it is still a big challenge to fabricate heterogeneous gel microspheres with excellent resolution and different material components in limited sizes. Here, we developed a multi-channel dynamic micromixer, which can use active mechanical mixing to achieve rapid mixing with multi-component materials and extrude the homogenized material. By changing the flow rate ratio of the solutions of the two components and by rapidly mixing in the micromixer, real-time concentration change of the mixed material at the outlet could be monitored in a process so-called “gradient printing”. By studying the mixing efficiency of the micromixer, its size and process parameters were optimized. Using the novel dynamic gradient printing method, the composition of the hydrogel microspheres can be distributed in any proportion and alginate heterogeneous gel microspheres with adjustable cell concentration were fabricated. The effects of cell concentration on cell viability and proliferation ability under three-dimensional culture conditions were also studied. The results showed that cells have very low death rate and can exchange substances within the microspheres. Due to the micromixing ability of the micromixers, the demand for biological reagents and materials such as cells, proteins, cytokines and other materials could be greatly reduced, which helps reduce the experimental cost and improve the feasibility of the method in practical use. The heterogeneous gel microsphere can be greatly valuable for research in various fields such as analytical chemistry, microarray, drug screening, and tissue culture.