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Three-dimensional (3D) printing enables patient-specific anatomical level productions with high adjustability and resolution in microstructures. With cost-effective manufacturing for high productivity, 3D printing has become a leading healthcare and pharmaceutical manufacturing technology, which is suitable for variety of applications including tissue engineering models, anatomical models, pharmacological design and validation model, medical apparatus and instruments. Today, 3D printing is offering clinical available medical products and platforms suitable for emerging research fields, including tissue and organ printing. In this review, our goal is to discuss progressive 3D printing technology and its application in medical materials. The additive overview also provides manufacturing techniques and printable materials.

The magnetic field has been proven to enhance bone tissue repair by affecting cell metabolic behavior. Magnetic nanoparticles are used as biomaterials due to their unique magnetic properties and good biocompatibility. Through endocytosis, entering the cell makes it easier to affect the physiological function of the cell. Once the magnetic particles are exposed to an external magnetic field, they will be rapidly magnetized. The magnetic particles and the magnetic field work together to enhance the effectiveness of their bone tissue repair treatment. This article reviews the common synthesis methods, the mechanism, and application of magnetic nanomaterials in the field of bone tissue repair.

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Recently, more and more attention has been paid to the development of a new generation of injectable bone cements that are bioactive, biodegradable and are able to have appropriate mechanical properties for treatment of vertebral compression fractures (VCFs). In this study, a novel PSC/CS composite cement with high content of PSC (a phytic acid-derived bioactive glass) was prepared and evaluated in both vitro and vivo. The PSC/CS cement showed excellent injectability, good resistance to disintegration, radiopacity and suitable mechanical properties. The in vitro test showed that the cement was bioactive, biocompatible and could maintain its shape sustainably, which made it possible to provide a long-term mechanical support for bone regeneration. Radiography, microcomputed tomography and histology of critical sized rabbit femoral condyle defects implanted with the cements proved the resorption and osteoinductivity of the cement. Compared with the PMMA and CSPC, there were more osteocyte and trabeculae at the Bone-Cement interface in the group PSC/CS cement. The volume of the residual bone cement suggested that PSC/CS had certain ability of degradation and the resorption rate was much lower than that of the CSPC cement. Together, the results indicated that the cement was a promising bone cement to treat the VCFs.

Large segmental bone defect repairing remains a big challenge in clinics, and synthetic bone grafts suitable for this purpose are still highly demanded. In this article, hydrophilic composite scaffolds (bioactive hollow particle (BHP)-gel scaffold) composed of bioactive hollow nanoparticles and cross-linked gelatin have been developed. The bioactive nanoparticles have a porous structure as well as high specific surface area; thus, they interact strongly with gelatin to overcome the swelling problem that a hydrophilic polymer scaffold will usually face. With this combination, these BHP-gel scaffolds showed porous structure and mechanical properties similar to those of the cancellous bone. They also showed excellent bioactivity and cell growth promotion performance in vitro. The best of them, namely, 10BHP-gel scaffold, was evaluated in vivo on a rat femur model, where it was found that the 5 mm segmental bone defect almost healed with new bone tissue formed in 12 weeks and the scaffold itself degraded at the same time. Thus, 10BHP-gel scaffold may become a potential bone graft for large segmental bone defect healing in the future.

Non‑small cell lung cancer (NSCLC) is one of the most severe malignant tumor types worldwide. Recent studies have reported an important role of PD‑L1 in mediating immune evasion in the tumor microenvironment. In addition, increasing research has indicated that the expression of PD‑L1 is related to the epithelial‑mesenchymal transition (EMT) process, but the related mechanisms remain to be explored. In the present study, we explored the molecular mechanisms underlying the regulation of PD‑L1 expression during the EMT process in NSCLC cells treated with transforming growth factor‑β1 (TGF‑β1) and fibroblast growth factor 2 (FGF2). The phenotypic alteration associated with EMT was evaluated by western blotting and confirmed by a wound‑healing assay. The results revealed that EMT markedly promoted the expression of PD‑L1 in the A549 cell line, while having no obvious influence on the H1650 and H1975 cells. Furthermore, the AKT pathway inhibitor LY294002, the ERK pathway inhibitor PD98059 and the TAK1 pathway inhibitor 5Z‑7 inhibited the expression of PD‑L1 in A549 and H1650 cells, but not in H1975 cells, during the EMT process. Moreover, our study indicated that the AKT, ERK and TAK1 pathways regulated the expression of PD‑L1 by mediating transportation of the transcription factor Stat3 and the p65 subunit of NF‑κB from the cytoplasm to the nucleus, with such findings determined by western blotting and flow cytometric analyses. Furthermore, the expression of PD‑L1 was significantly increased following treatment with gefitinib in a tumor xenograft model. In summary, our results support the role of ERK, AKT and TAK1 in mediating the expression of PD‑L1 during the EMT process, and indicate a promising strategy of PD‑L1‑targeted therapy for the clinical treatment of NSCLC.

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