International Journal of Bioprinting最新文献

The application of three-dimensional (3D) bioprinting has increased in the biomedical field. The lack of bioinks with both biocompatibility and printability is still a problem to be solved. Silk fibroin materials have good biocompatibility and have a broad application prospect in the field of biomedical materials. At present, most research usually involves Bombyx mori silk fibroin (BSF). However, BSF has low cell adhesion. Compared with BSF, Antheraea pernyi silk fibroin (ASF) isolated from typical non-mulberry silk exhibits a unique arginine-glycine-aspartate (RGD) sequence with good cell adhesion enhancement. In this study, we developed a bioink based on ASF for digital light processing (DLP) 3D bioprinting. The ASF-based bioinks (ASF-MA) were produced by a methacryloylation process using methacrylic anhydride (MA) to achieve the properties of photopolymerization reaction. The ASF-MA hydrogel has mechanical properties, biocompatibility, and especially cell adhesion. Meanwhile, we found that the ASF-MA hydrogels promoted the adhesion, migration, and proliferation of S16 cells. Hence, the ASF-MA hydrogels had the potential applications in biomedical fields.

Intramembranous ossification (IMO) and endochondral ossification (ECO) are two pathways of bone regeneration. The regeneration of most bone, such as limb bone, trunk bone, and skull base bone, mainly occurs in the form of endochondral ossification, which has also become one of the effective ways for bone tissue engineering. In this work, we prepared a well-structured and biocompatible methacrylated gelatin/polymethacrylic acid (GelMA/PMAA) hydrogel by digital light processing (DLP) printing technology, which could effectively chelate iron ions and continuously activate the hypoxia-inducible factor-1 alpha (HIF-1α) signaling pathway to promote the process of endochondral ossification and angiogenesis. The incorporation of PMAA endowed the hydrogel with remarkable viscoelasticity and high efficacy in chelation of iron ions, giving rise to the activation of HIF-1α signaling pathway, improving chondrogenic differentiation in the early stage, and facilitating vascularization in the later stage and bone remodeling. Therefore, the findings have significant implications on DLP printing technology of endochondral osteogenesis induced by the iron-chelating property of biological scaffold, which will provide an effective way in the development of novel bone regeneration.

72Several studies have been conducted to investigate the feasibility of customized nasal masks produced by three-dimensional (3D) facial imaging and printing for continuous positive airway pressure in adults and in premature mannequin. In addition to replicating the entire process, we applied the customized nasal mask to a premature patient who weighed less than 1,000 g. Facial scanning was performed. The study masks were manufactured using stereolithography with a 3D printer model Form3BL (FormLABS). Elastic 50 resin was used as the material. We verified the feasibility of the correct transmission of non-invasive ventilation and found that the mask improved the respiratory parameters and reduced the need for supplemental oxygen. The fraction of inspired oxygen (FiO₂) was lowered from 45%, which was the requirement when the traditional mask is used, to almost 21% when the nasal mask was applied to the premature patient, who was either in incubator or in kangaroo position. In view of these results, a clinical trial is being launched to evaluate the safety and efficacy of 3D-printed masks in extremely low birth weight (ELBW) infants. 3D printing provides an alternative for obtaining customized masks that may be more suitable for non-invasive ventilation in ELBW infants than traditional masks.

The common characteristics that make scaffolds suitable for human tissue substitutes include high porosity, microscale features, and pores interconnectivity. Too often, however, these characteristics are limiting factors for the scalability of different fabrication approaches, particularly in bioprinting techniques, in which either poor resolution, small areas, or slow processes hinder practical use in certain applications. An excellent example is bioengineered scaffolds for wound dressings, in which microscale pores in large surface-to-volume ratio scaffolds must be manufactured - ideally fast, precise, and cheap, and where conventional printing methods do not readily meet both ends. In this work, we propose an alternative vat photopolymerization technique to fabricate centimeter-scale scaffolds without losing resolution. We used laser beam shaping to first modify the profile of the voxels in 3D printing, resulting in a technology we refer to as light sheet stereolithography (LS-SLA). For proof of concept, we developed a system from commercially available off-the-shelf components to demonstrate strut thicknesses up to 12.8 ± 1.8 μm, tunable pore sizes ranging from 36 μm to 150 μm, and scaffold areas up to 21.4 mm × 20.6 mm printed in a short time. Furthermore, the potential to fabricate more complex and three-dimensional scaffolds was demonstrated with a structure composed of six layers, each rotated by 45° with respect to the previous. Besides the demonstrated high resolution and achievable large scaffold sizes, we found that LS-SLA has great potential for scaling-up of applied oriented technology for tissue engineering applications.

Cellulose-containing residue from agar production was incorporated as a filler into soy protein-based hydrogels and revalorized without further purification. Rheological assessment of these hydrogels was carried out in order to confirm their shear-thinning behavior and their suitability for 3D printing. It was observed that all hydrogels behaved as weak gels, which are suitable for 3D printing and have good printability and shape fidelity. The addition of cellulose did not cause chemical crosslinking but physical interactions, which led to morphological changes, thereby promoting hardness and shape recovery of the 3D-printed products. The hydrogel with the highest residue content (8 wt %) showed the highest value (78%) in shape recovery. Furthermore, the physicochemical characterization of these 3D-printed products revealed that although they have high swelling capacity, they preserve their integrity in wet conditions. These results suggested the potential of the 3D-printed products developed using residues without further purification to promote circular economy, increasing the efficiency in resources utilization.

438Severe skin injuries can cause serious problems, which could affect the patient's normal life, if not dealt properly in a timely and effective manner. It is an urgent requirement to develop personalized wound dressings with excellent antibacterial activity and biocompatibility to match the shape of the wound to facilitate clinical application. In this study, a bioink (GAQ) based on gelatin (Gel)/sodium alginate (SA)/ quaternized chitosan (QCS) was prepared, and GAQ hydrogel dressing grafting with dopamine (GADQ) was fabricated by an extrusion three-dimensional (3D) printing technology. QCS was synthesized by modifying quaternary ammonium group on chitosan, and its structure was successfully characterized by nuclear magnetic resonance (1H NMR) and Fourier-transform infrared spectroscopy (FT-IR). Our results showed that the GADQ hydrogel dressing that was double-crosslinked by EDC/ NHS and Ca²⁺ had good tensile strength, considerable swelling ratio, and effective antioxidation properties. It also showed that GADQ1.5% had 93.17% and 91.06% antibacterial activity against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, the relative survival ratios of fibroblast cells seeded on these hydrogels exceeded 350% after cultured for 7 days, which proved the biocompatibility of these hydrogels. Overall, this advanced 3D-printed GADQ1.5% hydrogels with effective antioxidation, excellent antibacterial activity and good biocompatibility had a considerable application potential for wound healing.

Three-dimensional (3D) bioprinting provides a promising strategy for tissue and organ engineering, and extracellular matrix (ECM)-derived bioinks greatly facilitate its applications in these areas. Decellularized sturgeon cartilage ECM (dSC-ECM)-derived bioinks for cartilage tissue engineering were fabricated with methacrylate-modified dSC-ECM (dSC-ECMMA) and sericin methacrylate (SerMA), which optimizedthe mechanical properties of their solidified hydrogels.dSC-ECM induces chondrocytes to form cell clusters and subsequently reduces their proliferation, but the proliferation of encapsulated chondrocytes was normal in solidified dSC-ECM-5 bioink samples, which contain 5 mg/mL dSC-ECMMA. Hence, this bioink was selected for further investigation. Lyophilized dSC-ECM-5 hydrogels showed connected pore microstructure, which is suitable for cell migration and nutrients transportation. ThisdSC-ECM-5 bioink exhibited high fidelity and good printability by testing via a 3D bioprinting system, and the chondrocytes loaded in printed hydrogel products were viable and able to grow, following incubation, in the cell culture medium. Solidified dSC-ECM-5 and SerMA bioinks loaded with chondrocytes were subcutaneously implanted into nude mice for 4 weeks to test the suitability of the bioink for cartilage tissue engineering. Compared to the SerMA bioink, the dSC-ECM-5 bioink significantly enhanced cartilage tissue regeneration and maturation in vivo, suggesting the potential of this bioink to be applied in cartilage tissue engineering in the future.

Biological tissues possess a high degree of structural complexity characterized by curvature and stratification of different tissue layers. Despite recent advances in in vitro technology, current engineering solutions do not comprise both of these features. In this paper, we present an integrated in silico-in vitro strategy for the design and fabrication of biological barriers with controlled curvature and architecture. Analytical and computational tools combined with advanced bioprinting methods are employed to optimize living inks for bioprinting-structured core-shell constructs based on alginate. A finite element model is used to compute the hindered diffusion and crosslinking phenomena involved in the formation of core-shell structures and to predict the width of the shell as a function of material parameters. Constructs with a solid alginate-based shell and a solid, liquid, or air core can be reproducibly printed using the workflow. As a proof of concept, epithelial cells and fibroblasts were bioprinted respectively in a liquid core (10 mg/mL Pluronic) and in a solid shell (20 mg/mL alginate plus 20 mg/mL gelatin, used for providing the cells with adhesive moieties). These constructs had a roundness of 97.6% and an average diameter of 1500 ±136 μm. Moreover, their viability was close to monolayer controls (74.12% ± 22.07%) after a week in culture, and the paracellular transport was twice that of cell-free constructs, indicating cell polarization.

Biomedical implants have recently shown excellent application potential in tissue repair and replacement. Applying three-dimensional (3D) printing to implant scaffold fabrication can help to address individual needs more precisely. Fourdimensional (4D) printing emerges rapidly based on the development of shape-responsive materials and design methods, which makes the production of dynamic functional implants possible. Smart implants can be pre-designed to respond to endogenous or exogenous stimuli and perform seamless integration with regular/ irregular tissue defects, defect-luminal organs, or curved structures via programmed shape morphing. At the same time, they offer great advantages in minimally invasive surgery due to the small-to-large volume transition. In addition, 4D-printed cellular scaffolds can generate extracellular matrix (ECM)-mimetic structures that interact with the contacting cells, expanding the possible sources of tissue/organ grafts and substitutes. This review summarizes the typical technologies and materials of 4D-printed scaffolds, and the programming designs and applications of these scaffolds are further highlighted. Finally, we propose the prospects and outlook of 4D-printed shape-morphing implants.

Three-dimensional printing (3DP) is a popular manufacturing technique with versatile potential for materials processing in tissue engineering and regenerative medicine. In particular, the repair and regeneration of significant bone defects remain as substantial clinical challenges that require biomaterial implants to maintain mechanical strength and porosity, which may be realized using 3DP. The rapid progress in 3DP development in the past decade warrants a bibliometric analysis to gain insights into its applications in bone tissue engineering (BTE). Here, we performed a comparative study using bibliometric methods for 3DP in bone repair and regeneration. A total of 2,025 articles were included, and the results showed an increase in the number of publications and relative research interest on 3DP annually worldwide. China was the leader in international cooperation in this field and also the largest contributor to the number of citations. The majority of articles in this field were published in the journal Biofabrication. Chen Y was the author who made the highest contribution to the included studies. The keywords included in the publications were mainly related to BTE and regenerative medicine (including "3DP techniques," "3DP materials," "bone regeneration strategies," and "bone disease therapeutics") for bone regeneration and repair. This bibliometric and visualized analysis provides significant insights into the historical development of 3DP in BTE from 2012 to 2022, which will be beneficial for scientists to conduct further investigations into this dynamic field.