Advances of 3D printing in gastroenterology and where it might be going

Gastrointestinal (GI) system comprises a great number of organs and tissues of various functions, both hollow and solid. However, it is still a less well-developed area for three-dimensional (3D) printing (3DP) applications compared to orthopedics. Clinical applications of 3DP in the GI system are presently restricted to preoperative planning, surgical guidance, and education for students, residents, and patients, either for laparoscopy or endoscopy. Several surgery-related accessories have been designed to facilitate surgical procedures. The results are promising but not adequately proven due to a lack of reasonable study design and proper comparisons. Other important requirements for GI systems in clinical scenarios are structural reconstruction, replacement, defect repair, drug screening, and delivery. Many 3D-printed decellularized, cell-seeded, or even bioprinted scaffolds have been studied; however, most studies were conducted on small animal or in vitro models. Although encouraging results have been obtained, there is still a long way to go before products compatible with humans in size, histology, and functions can be printed. The key points to achieving this goal are the printing material, cell type and source, and printing technology. The ultimate goal is to print tissue and organ substitutes with physiological functions for clinical purposes in both time- and cost-effective ways.