Three-Dimensional Cell Printing of Large-Volume Tissues: Application to Ear Regeneration

Abstract

The three-dimensional (3D) printing of large-volume cells, printed in a clinically relevant size, is one of the most important challenges in the field of tissue engineering. However, few studies have reported the fabrication of large-volume cell-printed constructs (LCCs). To create LCCs, appropriate fabrication conditions should be established: Factors involved include fabrication time, residence time, and temperature control of the cell-laden hydrogel in the syringe to ensure high cell viability and functionality. The prolonged time required for 3D printing of LCCs can reduce cell viability and result in insufficient functionality of the construct, because the cells are exposed to a harsh environment during the printing process. In this regard, we present an advanced 3D cell-printing system composed of a clean air workstation, a humidifier, and a Peltier system, which provides a suitable printing environment for the production of LCCs with high cell viability. We confirmed that the advanced 3D cell-printing system was capable of providing enhanced printability of hydrogels and fabricating an ear-shaped LCC with high cell viability. In vivo results for the ear-shaped LCC also showed that printed chondrocytes proliferated sufficiently and differentiated into cartilage tissue. Thus, we conclude that the advanced 3D cell-printing system is a versatile tool to create cell-printed constructs for the generation of large-volume tissues.

An Automated Addressable Microfluidics Device for Minimally Disruptive Manipulation of Cells and Fluids within Living Cultures

“…given that its targeting precision is limited only by the fabrication quality of the scaffold (to be refined tremendously by the anticipated explosion of 3D printed microfluidics [6,7]). This will shift the tissue engineering paradigm from integrating "blind" (i.e., open-loop) controls into the scaffold's material (e.g., timed drug release) to controlling cells in growing tissues interactively instead.…”

“…Specifically, scaffolds with dimensions larger than 3.8x3.8x3.8mm 3 are classified as large-volume, and constructs larger than that (e.g., 5.6x5.6x5.6 mm) have been found to result in areas of hypoxia after 3 days of culture. [5,6] Consequently, out of the three FDAapproved cellular therapies, one (LAVIV injectable fibroblasts for wrinkle treatment) is a suspension of disconnected cells and two (MACI knee cartilage implant and GINTUIT topical treatment of dental wounds) are flat strips of tissue. [2] No artificial 3D solid organs or complex tissues are currently available.…”

Ideal scaffold design for total ear reconstruction using a three‐dimensional printing technique

“…Several reports have introduced various methods and shapes of 3D‐printed ear models . Clinically, the previously reported 3D‐printed models are barely suitable for ear reconstruction.…”

“…However, these methods are associated with numerous limitations and varying degrees of success. Recently, a tissue‐engineering technique combining an optimal cell culture with a 3D‐printed scaffold has been researched to obtain a precise and delicate cartilage implant without donor‐site morbidity or major complications . Although many studies have presented a 3D‐printed cartilage framework, the literature about the ear reconstruction surgery using 3D printing is rare in a clinical setting.…”

“…Recently, a tissue‐engineering technique combining an optimal cell culture with a 3D‐printed scaffold has been researched to obtain a precise and delicate cartilage implant without donor‐site morbidity or major complications . Although many studies have presented a 3D‐printed cartilage framework, the literature about the ear reconstruction surgery using 3D printing is rare in a clinical setting. The likely reason for this is that most researchers concentrate on the tissue‐engineering technique without a specific operative plan regarding how to reconstruct ear deformities using the resulting 3D scaffold.…”