Gradient Hydrogel Construct Based on an Improved Cell Assembling System

In this study, a two-step crosslinking method derived from commercial rapid prototyping equipment was used to fabricate a gradient hydrogel scaffold in vitro. This system contained two types of nozzles; one was double-nozzle unit, used for relatively simple gradient hydrogel scaffold composed of two nonmiscible hydrogel materials. The other was single nozzle that was used for mixing a gradient hydrogel scaffold composed of two types of hydrogel materials. Different types of scaffolds were formed by modifying the gradient in one of the relevant nozzles. To improve the extrusion controlling effect, accessorial parameters were introduced. A 3D gradient construct containing neuron cells and Schwann cells was fabricated and cultured for 7 days. This construct was helpful in designing a gradient mode to observe the relationship between different cells in vitro. This work has improved tissue-engineering techniques for later manufacturing of very complicated organ analogs.