*Review* **Chitosans for Tissue Repair and Organ Three-Dimensional (3D) Bioprinting**

### **Shenglong Li 1, Xiaohong Tian 1, Jun Fan 1, Hao Tong 1, Qiang Ao 1 and Xiaohong Wang 1,2,\***


Received: 24 October 2019; Accepted: 5 November 2019; Published: 11 November 2019

**Abstract:** Chitosan is a unique natural resourced polysaccharide derived from chitin with special biocompatibility, biodegradability, and antimicrobial activity. During the past three decades, chitosan has gradually become an excellent candidate for various biomedical applications with prominent characteristics. Chitosan molecules can be chemically modified, adapting to all kinds of cells in the body, and endowed with specific biochemical and physiological functions. In this review, the intrinsic/extrinsic properties of chitosan molecules in skin, bone, cartilage, liver tissue repair, and organ three-dimensional (3D) bioprinting have been outlined. Several successful models for large scale-up vascularized and innervated organ 3D bioprinting have been demonstrated. Challenges and perspectives in future complex organ 3D bioprinting areas have been analyzed.

**Keywords:** 3D bioprinting; chitosan; chitin; tissue repair; rapid prototyping (RP); implantable bioartificial organs
