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Tissue scaffolds need to have anisotropic mechanical properties and a porous structure to meet the needs of different tissues and organs. This report presents results of a study on an especially-designed 3D printing method with oxidized nanocellulose and gelatin, analyzes the servo principle of pneumatic condensing extrusion 3D printer, and proposes a hexagonal algorithm. For the purpose of this study, a printing process file was written by G code, physical and mechanical performance of the 3D scaffolds was evaluated with Solidworks simulation, the porous structure and pressure-pull performance of the printed 3D scaffolds was observed by SEM, and experiments were conducted to measure their bio-compatibility. The study draws the conclusion that scaffolds thus printed have a highly porous structure and anisotropic mechanical properties.

For tissue engineering applications tissue scaffolds need to have a porous structure to meet the needs of cell proliferation/differentiation, vascularisation and sufficient mechanical strength for the specific tissue. Here we report the results of a study of the 3D printing process for composite materials based on oxidized nanocellulose and gelatin, that was optimised through measuring rheological properties of different batches of materials after different crosslinking times, simulation of the pneumatic extrusion process and 3D scaffolds fabrication with Solidworks Flow Simulation, observation of its porous structure by SEM, measurement of pressure-pull performance, and experiments aimed at finding out the vitro cytotoxicity and cell morphology. The materials printed are highly porous scaffolds with good mechanical properties.

As one of the most abundant wild herbs in nature, the Humulus japonicus stem (HJS) is a new low-cost source of cellulosic material. In this work, cellulose nanocrystals (CNCs) were isolated from HJS using acid hydrolysis. The influence of high temperature pretreatment (HT pretreatment) on the properties and yields of these HT-HJS (HJS fibers after HT pretreatment at different temperatures) and HT-CNCs (CNCs prepared from the HT-HJS) was studied. The results showed that there was no variation of the chemical structure among the HT-HJS and HT-CNCs. The thermal stabilities and crystallinities of the HT-HJS were higher than bleached HJS. The average diameters of the HT-CNCs were significantly smaller while the average aspect ratios of them were obviously bigger than the CNCs, and the biggest average aspect ratio of HT140-CNCs (63.40) was almost twice of CNCs (32.00). Compared with the CNCs (70.05%, 212.8°C), the crystallinity and initial degradation temperature also showed increase for the HT-CNCs and increased up to maximum of 86.93% and 227.5°C for the HT160-CNCs., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Early reports have demonstrated the feasibility of oxidized dextran/gelatin (OD/GEL) hydrogel for tissue engineering applications and the printability of OD/GEL hydrogel for 3D printing scaffolds, but adequate insight into fabricated OD/GEL scaffolds is lacking. In the present study, we prepared (cellulose nanocrystal) CNC/OD/GEL hydrogels and fabricated CNC/OD/GEL scaffolds by 3D printing. The properties of CNC/OD/GEL hydrogels were investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. The process of 3D printing of hydrogels was optimized, and the influence of the OD and CNC contents on the printability of CNC/OD/GEL hydrogels was investigated by studying the width of the printed filaments. The uniaxial compression test was performed to study the effects of the OD and CNC contents on the breaking strength and elastic modulus of CNC/OD/GEL scaffolds. In addition, the uniaxial compression test was also performed to determine the optimum mass ratio and crosslinking time of OD and GEL. The effects of the CNC content on scaffold shrinkage, scaffold swelling and scaffold porosity were further studied. The biocompatibility of a CNC0.4OD2G2 scaffold was also investigated by Cell Counting Kit-8 (CCK-8) and Hoechst 33342/PI double-staining assays. Collectively, the results confirmed the good potential of the CNC/OD/GEL hydrogels as 3D bioink for application in tissue repair. [ABSTRACT FROM AUTHOR]

For tissue engineering applications tissue scaffolds need to have a porous structure to meet the needs of cell proliferation/differentiation, vascularisation and sufficient mechanical strength for the specific tissue. Here we report the results of a study of the 3D printing process for composite materials based on oxidized nanocellulose and gelatin, that was optimised through measuring rheological properties of different batches of materials after different crosslinking times, simulation of the pneumatic extrusion process and 3D scaffolds fabrication with Solidworks Flow Simulation, observation of its porous structure by SEM, measurement of pressure-pull performance, and experiments aimed at finding out the vitro cytotoxicity and cell morphology. The materials printed are highly porous scaffolds with good mechanical properties. [ABSTRACT FROM AUTHOR]