3D printed hydrogels with oxidized cellulose nanofibers and silk fibroin for the proliferation of lung epithelial stem cells

Abstract

A novel biomaterial ink consisting of regenerated silk fibroin (SF) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose (OBC) nanofibrils was developed for 3D printing lung tissue scaffold. Silk fibroin backbones were cross-linked using horseradish peroxide/H 2 O 2 to form printed hydrogel scaffolds. OBC with a concentration of 7wt% increased the viscosity of inks during the printing process and further improved the shape fidelity of the scaffolds. Rheological measurements and image analyses were performed to evaluate inks printability and print shape fidelity. Three-dimensional construct with ten layers could be printed with ink of 1SF-2OBC (SF/OBC = 1/2, w/w). The composite hydrogel of 1SF-1OBC (SF/OBC = 1/1, w/w) printed at 25 °C exhibited a significantly improved compressive strength of 267 ± 13 kPa and a compressive stiffness of 325 ± 14 kPa at 30% strain, respectively. The optimized printing parameters for 1SF-1OBC were 0.3 bar of printing pressure, 45 mm/s of printing speed and 410 μm of nozzle diameter. Furthermore, OBC nanofibrils could be induced to align along the print lines over 60% degree of orientation, which were analyzed by SEM and X-ray diffraction. The orientation of OBC nanofibrils along print lines provided physical cues for guiding the orientation of lung epithelial stem cells, which maintained the ability to proliferate and kept epithelial phenotype after 7 days’ culture. The 3D printed SF-OBC scaffolds are promising for applications in lung tissue engineering. Electronic supplementary material The online version of this article (10.1007/s10570-020-03526-7) contains supplementary material, which is available to authorized users.

Bacterial nanocellulose: engineering, production, and applications

“…A German group developed BASYC® (Bacterial Cellulose Synthetized), a tubular biomaterial for microsurgery of arteries and veins, with a focus on vascular applications [ 117 ]. Huang et al (2021) used a silk fibroin-TEMPO oxidized BNC for high precision 3-D bioprinting of lung tissue scaffold [ 118 ]. Other potential BNC tissue engineering applications include ear cartilage, brain implants, urinary conduits, tympanic membrane, and vocal folds [ 119 ].…”

Implications for Extracellular Matrix Interactions With Human Lung Basal Stem Cells in Lung Development, Disease, and Airway Modeling

“…Most recently, progress in the development and use of synthetic ECM materials for cell culture have emerged. Biomaterial inks have been developed from regenerated silk fibroin (SF) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose (OBC) nanofibrils and engineered for 3D printing of lung tissue scaffolds ( Huang et al, 2020 ). Another group has developed a tissue-specific hybrid bioinks from the naturally occurring polymer alginate along with ECM derived from decellularized tissue ( De Santis et al, 2021 ).…”

“…The results of this study do demonstrate that a combination of exogenously and endogenously derived ECM materials supports epithelial development and offers the potential of printing customized airway scaffolds which has not yet been achieved with native ECM alone. Huang suggested that by manipulating the alignment of the OBC nanofibrils within the scaffold, ECM remodeling could be recreated and consequently manipulate cell fate ( Huang et al, 2020 ). Unfortunately, neither study comprehensively evaluated functional differentiation, mucociliary clearance, and regenerative capacity, all core criteria in creating bio scaffolds for lung repair.…”

“…Unfortunately, neither study comprehensively evaluated functional differentiation, mucociliary clearance, and regenerative capacity, all core criteria in creating bio scaffolds for lung repair. ( Huang et al, 2020 ) ( Huang et al, 2020 ). While extensive validation is necessary before the creation of functional organs derived from decellularized ECM scaffolds is feasible, these studies do support the notion that ECMs derived from native tissues produce more physiologic BC populations and airway epithelia in an in vitro setting.…”

Rheological and Printability Assessments on Biomaterial Inks of Nanocellulose/Photo-Crosslinkable Biopolymer in Light-Aided 3D Printing

“…CNFs can be either printed as a monocomponent hydrogel as a platform biomaterial (Ajdary et al, 2019) or more often in binary ink formulations with other biopolymers, such as gelatin and alginate (Markstedt et al, 2015;Ojansivu et al, 2019), where CNFs are more often seen as a rheological modifier to facilitate the extrudability/printability and to promote the shape fidelity performance of the formulated bioink. In order to improve the ink fidelity, different crosslinking strategies such as ionic crosslinking (Rees et al, 2015), thermal crosslinking (Xu et al, 2018b), enzymatic crosslinking (Huang et al, 2020), and photo-crosslinking (Ma et al, 2020) were implemented in previous studies. In an up-to-date research context, light-aided 3D bioprinting is a prevailing approach for biofabrication.…”