RESUMO
3D bioprinting technology provides programmable and customizable platforms to engineer cell-laden constructs mimicking human tissues for a wide range of biomedical applications. However, the encapsulated cells are often restricted in spreading and proliferation by dense biomaterial networks from gelation of bioinks. Herein, a cell-benign approach is reported to directly bioprint porous-structured hydrogel constructs by using an aqueous two-phase emulsion bioink. The bioink, which contains two immiscible aqueous phases of cell/gelatin methacryloyl (GelMA) mixture and poly(ethylene oxide) (PEO), is photocrosslinked to fabricate predesigned cell-laden hydrogel constructs by extrusion bioprinting or digital micromirror device-based stereolithographic bioprinting. The porous structure of the 3D-bioprinted hydrogel construct is formed by subsequently removing the PEO phase from the photocrosslinked GelMA hydrogel. Three different cell types (human hepatocellular carcinoma cells, human umbilical vein endothelial cells, and NIH/3T3 mouse embryonic fibroblasts) within the 3D-bioprinted porous hydrogel patterns show enhanced cell viability, spreading, and proliferation compared to the standard (i.e., nonporous) hydrogel constructs. The 3D bioprinting strategy is believed to provide a robust and versatile platform to engineer porous-structured tissue constructs and their models for a variety of applications in tissue engineering, regenerative medicine, drug development, and personalized therapeutics.
RESUMO
BACKGROUND: Severe pectus excavatum (PE) may be concomitant with congenital cystic lung lesions (CCLLs) that also require surgery. It is ideal to correct these two deformities concurrently, but the safety and efficacy of a simultaneous surgical technique remain unknown. METHODS: Between 2007 and 2017, 635 patients with severe PE were admitted at our medical center. Eight patients underwent minimally invasive repair of PE and lobectomy simultaneously. The patient characteristics and operative data were analyzed and compared with another group of patients who underwent lobectomy alone for contemporaneous CCLLs. RESULTS: The severity of PE (mean Haller index 5.70) and CCLLs were confirmed by computed tomography (CT). Simultaneous minimally invasive repair and lobectomy were performed successfully. There were no significant differences in the mean blood loss (14 mL/kg), the mean weaning time from mechanical ventilation (900 minutes) and the mean hospital stay (16 days) (P>0.05). The mean operative time (170 minutes) was extended, as expected (P=0.02). With a mean follow-up of 22 months, the overall cosmetic results were good. CONCLUSIONS: Simultaneous minimally invasive repair and lobectomy appears to be a technically safe and reliable method for the treatment of concurrent PE and CCLLs, although further studies are needed in the long-term follow-up.
RESUMO
Bioceramic scaffolds with desired bone regeneration functions have the potential to become real alternatives to autologous bone grafts for reconstruction of load-bearing and critical-sized segmental bone defects. The aim of this paper was to develop a layered scaffold structure that has the biodegradable function of common monolithic scaffolds and adequate mechanical function for surgical fixing and after surgery support. The exemplary case of this study is assumed to be a large-segment tibia or femur bone repair. The layered scaffold structure consists of a macro porous hydroxyapatite-wollastonite layer and a strong dense zirconia matrix dense layer. The bio-functional scaffold layer with interconnected freeze-dried porous structures shows excellent apatite formation, cell attachment, and cell proliferation capabilities. The mechanical functional layer provides a bending strength matching that of the compact bone.
