International Journal of Bioprinting最新文献

Bioink preparation is an important yet challenging step for bioprinting with hydrogels, as it involves fast and homogeneous mixing of various viscous components. In this study, we have developed an automated active mixing platform (AAMP), which allows for high-quality preparation of hydrogel bioinks. The design of AAMP, adapted from syringe pumps, provides many advantages, including low cost, automated control, high precision, customizability, and great cytocompatibility, as well as the potential to intelligently detect the homogeneity. To demonstrate the capability of AAMP, mixing of different hydrogel components, including alginate and xanthan gum with and without Ca²⁺, alginate and Laponite, PEGDMA and xanthan gum, was performed to investigate an alginate hydrogel preparation process. Colorimetric analyses were carried out to evaluate the mixing outcome with AAMP. Result showed that AAMP can prepare homogeneous hydrogel mixing in a fast and automated fashion. A multiphysics COMSOL simulation is carried out to further validate the results. Moreover, cell viability and proliferation study were performed in a cell encapsulation mixing experiment to validate the cytocompatibility of the AAMP. The AAMP has demonstrated great capability in hydrogel bioink preparation and could therefore holds great promise and wide applications in bioprinting and tissue engineering.

3D bioprinting technology is a well-established and promising advanced fabrication technique that utilizes potential biomaterials as bioinks to replace lost skin and promote new tissue regeneration. Cutaneous regenerative biomaterials are highly commended since they benefit patients with larger wound sizes and irregular wound shapes compared to the painstaking split-skin graft. This study aimed to fabricate biocompatible, biodegradable, and printable bioinks as a cutaneous substitute that leads to newly formed tissue post-transplantation. Briefly, gelatin (GE) and polyvinyl alcohol (PVA) bioinks were prepared in various concentrations (w/v); GE (6% GE: 0% PVA), GPVA3 (6% GE: 3% PVA), and GPVA5 (6% GE: 5% PVA), followed by 0.1% (w/v) genipin (GNP) crosslinking to achieve optimum printability. According to the results, GPVA5_GNP significantly presented at least 590.93 ± 164.7% of swelling ratio capacity and optimal water vapor transmission rate (WVTR), which is <1500 g/m²/h to maintain the moisture of the wound microenvironment. Besides, GPVA5_GNP is also more durable than other hydrogels with the slowest biodegradation rate of 0.018 ± 0.08 mg/h. The increasing amount of PVA improved the rheological properties of the hydrogels, leading the GPVA5_GNP to have the highest viscosity, around 3.0 ± 0.06 Pa.s. It allows a better performance of bioinks printability via extrusion technique. Moreover, the cross-section of the microstructure hydrogels showed the average pore sizes >100 μm with excellent interconnected porosity. X-ray diffraction (XRD) analysis showed that the hydrogels maintain their amorphous properties and were well-distributed through energy dispersive X-ray after crosslinking. Furthermore, there had no substantial functional group changes, as observed by Fourier transform infrared spectroscopy, after the addition of crosslinker. In addition, GPVA hydrogels were biocompatible to the cells, effectively demonstrating >90% of cell viability. In conclusion, GPVA hydrogels crosslinked with GNP, as prospective bioinks, exhibited the superior properties necessary for wound healing treatment.

3D-printed scaffolds that forge a new path for regenerative medicine are widely used in breast reconstruction due to their personalized shape and adjustable mechanical properties. However, the elastic modulus of present breast scaffolds is significantly higher than that of native breast tissue, leading to insufficient stimulation for cell differentiation and tissue formation. In addition, the lack of a tissue-like environment results in breast scaffolds being difficult to promote cell growth. This paper presents a geometrically new scaffold, featuring a triply periodic minimal surface (TPMS) that ensures structural stability and multiple parallel channels that can modulate elastic modulus as required. The geometrical parameters for TPMS and parallel channels were optimized to obtain ideal elastic modulus and permeability through numerical simulations. The topologically optimized scaffold integrated with two types of structures was then fabricated using fused deposition modeling. Finally, the poly (ethylene glycol) diacrylate/gelatin methacrylate hydrogel loaded with human adipose-derived stem cells was incorporated into the scaffold by perfusion and ultraviolet curing for improvement of the cell growth environment. Compressive experiments were also performed to verify the mechanical performance of the scaffold, demonstrating high structural stability, appropriate tissue-like elastic modulus (0.2 - 0.83 MPa), and rebound capability (80% of the original height). In addition, the scaffold exhibited a wide energy absorption window, offering reliable load buffering capability. The biocompatibility was also confirmed by cell live/dead staining assay.

181Biofabrication approaches, such as three-dimensional (3D) bioprinting of hydrogels, have recently garnered increasing attention, especially in the construction of 3D structures that mimic the complexity of tissues and organs with the capacity for cytocompatibility and post-printing cellular development. However, some printed gels show poor stability and maintain less shape fidelity if parameters such as polymer nature, viscosity, shear-thinning behavior, and crosslinking are affected. Therefore, researchers have incorporated various nanomaterials as bioactive fillers into polymeric hydrogels to address these limitations. Carbon-family nanomaterials (CFNs), hydroxyapatites, nanosilicates, and strontium carbonates have been incorporated into printed gels for application in various biomedical fields. In this review, following the compilation of research publications on CFNs-containing printable gels in various tissue engineering applications, we discuss the types of bioprinters, the prerequisites of bioink and biomaterial ink, as well as the progress and challenges of CFNs-containing printable gels in this field.

In this study, novel scaffolds based on natural polymers were developed by combining 3D printing (3DP) and electrospinning (ES) techniques. ES ink was prepared with gelatin and poly(vinyl alcohol) (PVA), while 3DP ink was prepared with gelatin and chitin. Different biopolymers were used to confer unique properties to each ink and obtain a multilayered scaffold suitable for tissue regeneration. First, gelatin is able to exhibit the characteristics needed for both inks since gelatin chains contain arginineglycine-aspartic (RGD) motifs, an important sequence in the promotion of cell adhesion, which gives gelatin an improved biological behavior in comparison to other polymers. Additionally, PVA was selected for ES ink to facilitate gelatin spinnability, and chitin was incorporated into 3DP ink as reinforcement to provide mechanical support and protection to the overall design. In this work, chitin was extracted from fruit fly pupae. The high extraction yield and purity of the chitin obtained from the fruit fly pupae confirmed that this pupa is an alternative source to produce chitin. Once the chitin was characterized, both inks were prepared and rheological analysis was carried out in order to confirm the shear thinning behavior required for additive manufacturing processes. The combination of 3DP and ES processes resulted in porous scaffolds, which were proven biocompatible, highlighting their potential for biomedical applications.

In order to generate a high-performance personalized biological fixation plate with matching mechanical properties and biocompatibility, reverse reconstruction and fracture reduction of a femur were performed by combining reverse and forward approaches, and the surface was extracted according to the installation position of the plate to complete plate modeling by shifting, thickening, and performing other operations. Subsequently, topology optimization and three-dimensional (3D) printing were performed, and the properties of the manufactured plate were probed. The results showed that the maximum displacement of the plate was 4.13 mm near the femoral head, the maximum stress was 5.15e² MPa on both sides of the plate across its entire length, and the stress concentration decreased following topology optimization. The plate with optimized topology and filled with porous structure has a good filling effect. The final mass of the H-shaped plate was 12.05 g, while that of the B-shaped plate was 11.05 g, which dropped by 20.93% and 27.49%, respectively, compared with the original plate. The surface of the 3D-printed plate was bright and new, with a clear pore structure and good lap joint. The B-shaped and H-shaped plates were closely dovetailed with the host bone, which met the assembly requirements. This lays a foundation for the direct application of a high-performance personalized biological fixation plate.

In the present work, we used three-dimensional (3D) printing technology to make a polylactic acid (PLA) amniotic fornical ring (AFR) for ocular surface reconstruction. This work is a retrospective and interventional case series of patients with ocular surface diseases who underwent either personalized 3D-printed AFR-assisted amniotic membrane transplantation (AMT) or sutured AMT (SAMT). Patient epidemiology, treatment, operative duration, epithelial healing time, retention time, vision changes, morbidity, and costs were analyzed. Thirty-one patients (40 eyes) and 19 patients (22 eyes) were enrolled in the 3D-printed AFR group and the SAMT group, respectively. The clinical indications of AFR and SAMT were similar, such as corneal and/or conjunctival epithelial defects due to chemical burns, thermal burns, Stevens-Johnson syndrome (SJS), or toxic epidermal necrolysis (TEN). The mean dissolution time was 15 ± 11 days in the AFR group, compared with 14 ± 7 days in the SAMT group. The percentage of healed corneal area was 90.91% (66.10%-100.00%) for AFR and 93.67% (60.23%-100.00%) for SAMT. The median time for corneal epithelial healing was 14 (7-75) days in the AFR group and 30 (14-55) days in the suture AMT group. There were no significant differences in the initial visual acuity, final visual acuity, or improvement in visual acuity between the two groups. The operation duration in the AFR group was significantly shorter than that in the SAMT group. Regarding the cost analysis, the average cost per eye in the AFR group was significantly lower than that in the SAMT group. Furthermore, 3D-printed and sterile AFR showed no obvious side effects on the eyes. Our results suggested that 3D-printed PLA scaffolds could be used as an AFR device for ocular surface disease. In addition, personalized 3D-printed AFR is superior to conventional AMT in operation duration and cost effectiveness, thereby reducing the financial burden on our health care system.

Articular osteochondral defects are quite common in clinical practice, and tissue engineering techniques can offer a promising therapeutic option to address this issue.The articular osteochondral unit comprises hyaline cartilage, calcified cartilage zone (CCZ), and subchondral bone.As the interface layer of articular cartilage and bone, the CCZ plays an essentialpart in stress transmission and microenvironmental regulation.Osteochondral scaffolds with the interface structure for defect repair are the future direction of tissue engineering. Three-dimensional (3D) printing has the advantages of speed, precision, and personalized customization, which can satisfy the requirements of irregular geometry, differentiated composition, and multilayered structure of articular osteochondral scaffolds with boundary layer structure. This paper summarizes the anatomy, physiology, pathology, and restoration mechanisms of the articular osteochondral unit, and reviews the necessity for a boundary layer structure in osteochondral tissue engineering scaffolds and the strategy for constructing the scaffolds using 3D printing. In the future, we should not only strengthen the basic research on osteochondral structural units, but also actively explore the application of 3D printing technology in osteochondral tissue engineering. This will enable better functional and structural bionics of the scaffold, which ultimately improve the repair of osteochondral defects caused by various diseases.