Effects of scaffold design parameters on the printing accuracy for melt electrowriting

Abstract

Melt electrowriting (MEW), a high-resolution additive manufacturing technique, has been used to fabricate high-fidelity fibrous scaffolds. However, the printing accuracy of MEW is deteriorated by the occurrence of fiber deviation phenomena during the scaffold-fabrication process, which limits a broader application of this technique. Herein, an efficient universal index (Ip), along with an evaluation protocol is advanced to evaluate the printing accuracy of MEW. Then, experimental results show that key scaffold design parameters (fiber diameter (df), inter-fiber distance (Sf), and layer number (N)) can affect the value of Ip significantly. In general, the increase of df and N and the decrease of Sf can lead to inferior printing accuracy, accompanied by a decrement in Ip values. Moreover, the interplay between df and Sf on the printing accuracy is further analyzed based on a variable k (Sf over df). The variables k and N are subsequently identified as the two fundamental scaffold design parameters that affect the printing accuracy. Lastly, residual charge densities entrapped in the scaffolds are measured, thereby furnishing mechanistic insights into the effects of charge on the printing accuracy.