Optimizing material and manufacturing process for PEGDA/CNF aerogel scaffold

Cellulose nano fibril (CNF) aerogel, which is provided with high porosity, ultralow density and biodegradable ability, is a promising material for tissue engineering scaffold. Restricted by its poor mechanical properties, common CNF aerogel is unable to make scaffold with customized 3D structures. In order to make it useful in tissue engineering, the synthetic polymer Poly(ethylene glycol) diacrylate (PEGDA) has been chosen to mix with CNF solution to form a kind of composite bio-resin, which is ready for stereolithography. Our former study has proved the printability of the bio-resin and the biocompatibility of the CNF aerogel scaffold. But the relationship among its properties, material component and manufacturing condition has not been systematically studied. Thus an attempt is made to study and optimize the process factors that govern the aerogel scaffold's property by using Taguchi experiment design in this work, where four main factors of material and fabrication process: the content of PEGDA, the content of CNF, the size of CNF and the pre-freeze temperature have been chosen to make a discussion of their effect on the aerogel scaffold's properties including its porosity, mechanical property, micro-structure and so on. An orthogonal array of experiment is developed. It has the least number of experimental runs with desired process factor settings. The results analyzed by the tool of Analysis of Variance (ANOVA) show that different factor has various degrees of effect on different properties. Finally the optimized factors are acquired by screening the experiments data.