Organ transplantation can save the lives of many patients whose organs have failed or have been damaged by disease or injury. However, more than 120,000 people in the US alone are on waiting lists for organs, and others face chronic problems due to the long-term damaging effects of post-transplant immunosuppression. There's a large and growing need for an alternative to the organ transplant waiting list. 3D bioprinting has emerged as an exciting new tool with the potential to eliminate the organ transplant waiting list and avoid transplant rejection.

3D bioprinting mainly uses computer-aided additive manufacturing (CAD) technology to precisely control the position, combination, and interaction of biological materials, biological cells, and growth factors in the overall 3D structure, to make them biologically active. The goal of this technology is to fabricate biomedical parts with functions close to or better than target tissues or biological organs, which can mimic the behavior of natural living systems.

Due to the growing market demand for customized drugs and medical devices, 3D bioprinting has become one of the most revolutionary and influential advanced tools in recent years. This technology can be applied to drug research, stem cell regeneration, tumor modeling, disease modeling, disease diagnosis and other medical directions. There are three important stages in the production of biofabrication products (e.g., printed tissues or organs), including imaging and design, bioink selection, and printing and maturation.

※ Imaging and design
This process requires the creation of a virtual computer-aided design file, which contains the necessary 3D information to inform the printer where and what to print during the manufacturing process. CAD software can convert medical images (MRI scans) into virtual 3D formats.

※ Bioink selection
A key factor in the 3D bioprinting process is the design of the bioink. Bioinks are formed by combining cells and various biocompatible materials, which are subsequently printed into specific shapes to produce tissue-like 3D structures.

An ideal bioink should possess the desired physicochemical and biological properties, such as proper mechanical, rheological, and chemical characteristics, as well as excellent printability and biocompatibility.

※ Printing and maturation
Depending on the inkjet mechanism, there are a number of bio-printing technologies available. The main 3D bioprinting modalities can generally be classified as: inkjet bioprinting, laser-assisted bioprinting (LaBP), and extrusion-based bioprinting (EBB).

Inkjet-based bioprinting is a type of bioprinting technology based on the conventional inkjet printing process with desktop inkjet printers, which has the characteristics of high print speed, low cost and wide availability. Scientists have made great progress in patterning molecules, cells and organs by inkjet printing. In addition, studies have shown that mammalian cells can be successfully printed by inkjet bioprinting and retain their functions, which has good prospects for creating living tissue structures or organs.

Laser-assisted bioprinting (LAB) technology is one of the main molding technologies for bioprinting, which has broad development prospects in the field of regenerative medicine. Its physical mechanism makes it possible to print cells and liquid materials with a cell-level resolution. Researchers have demonstrated the feasibility of using laser-based technology to print cells, such as human dermal fibroblasts, mouse C2C12 myoblasts, bovine pulmonary artery endothelial cells (BPAECs), breast cancer (MCF-7) cells and rat neural stem cells.

When it comes to extrusion-based bioprinting (EBB), there are three main types of extrusions, namely pneumatic driven, piston driven, and screw driven. EBB can be used to fabricate bioprinted organs, which not only decreases the dependency on organ donation but also provides a promising alternative to animal testing.

Author's Bio: 

A big fan of biological science and technology