A review on cell damage,viability,and functionality during 3D bioprinting

Three-dimensional(3D)bioprinting fabricates 3D functional tissues/organs by accurately depositing the bioink composed of the biological materials and living cells.Even though 3D bioprinting techniques have experienced significant advancement over the past decades,it remains challenging for 3D bioprinting to artificially fabricate functional tissues/organs with high post-printing cell viability and functionality since cells endure various types of stress during the bioprinting process.Generally,cell viability which is affected by several factors including the stress and the environmental factors,such as pH and temperature,is mainly determined by the magnitude and duration of the stress imposed on the cells with poorer cell viability under a higher stress and a longer duration condition.The maintenance of high cell viability especially for those vulnerable cells,such as stem cells which are more sensitive to multiple stresses,is a key initial step to ensure the functionality of the artificial tissues/organs.In addition,maintaining the pluripotency of the cells such as proliferation and differentiation abilities is also essential for the 3D-bioprinted tissues/organs to be similar to native tissues/organs.This review discusses various pathways triggering cell damage and the major factors affecting cell viability during different bioprinting processes,summarizes the studies on cell viabilities and functionalities in different bioprinting processes,and presents several potential approaches to protect cells from injuries to ensure high cell viability and functionality.

Inkjet 3D bioprinting for tissue engineering and pharmaceutics

3D bioprinting has the capability to create 3D cellular constructs with the desired shape using a layer-by-layer approach.Inkjet 3D bioprinting,as a key component of 3D bioprinting,relies on the deposition of cell-laden droplets to create native-like tissues/organs which are envisioned to be transplantable into human body for replacing damaged ones.Benefiting from its superiorities such as high printing resolution and deposition accuracy,inkjet 3D bioprinting has been widely applied to various areas,including,but not limited to,tissue engineering and drug screening in pharmaceutics.Even though inkjet 3D bioprinting has proved its feasibility and versatility in various fields,the current applications of inkjet 3D bioprinting are still limited by the printing technique and material selection.This review,which specifically focuses on inkjet 3D bioprinting,firstly summarizes the techniques,materials,and applications of inkjet 3D bioprinting in tissue engineering and drug screening,subsequently discusses the major challenges that inkjet 3D bioprinting is facing,and lastly summarizes potential solutions to those challenges.