Dispensing Systems
Whitepapers and Presentations

Robust True Direct 3D Printing Technology for Human Tissue Engineering

Originally presented at 2007 International Manufacturing Science And Engineering Conference MSEC2007, October 15-17, 2007, Atlanta, Georgia, USA

Abstract

In the field of tissue engineering, numerous solid freeform fabrication (SFF) or rapid prototyping (RP) techniques have been employed to fabricate specially organized 3D structures such as scaffolds. Some such technologies include, but are not limited to, laminated object manufacturing (LOM), 3D printing (3-DP) or ink-jet printing, selective laser sintering (SLS), and fused deposition modeling (FDM). These techniques are capable of rapidly producing highly complex 3d scaffolds or other biomedical structures with the aid of a computer-aided design (CAD) system. However, they suffer from lack of consistency and repeatability, since most of these processes are not fully controlled and cannot reproduce the previous work with accuracy. Also, these techniques (excluding FDM) are not truly direct print processes. Certain material removing steps are involved, which in turn increases the complexity and the cost of fabrication. The FDM process has good repeatability; however, the materials that can be used are limited due to the high temperature needed to melt the feedstock. Some researchers also reported that the scaffolds fabricated by FDM lack consistency in the z-direction.

In this paper, we present a true 3D printing direct print technology for repeatedly producing scaffolds and other biomedical structures for human tissue engineering with the aid of our Computer Aided Biological (CAB) tool. Unlike other SFF techniques mentioned above, our dispensing systems direct-print process fabricates scaffolds or other complex 3D structures by extruding (dispensing) a liquid material onto the substrate with a prescribed pattern generated by a CAD program. This can be a layer-by-layer 2.5 dimension build or a true 3d build using our 3D printing machines. The dispensed liquid material then polymerizes or solidifies, to form a solid structure. The flexibility in the types of materials that can be extruded ranges from polymers to living cells, encapsulated in the proper material. True 3D printing structures are now possible on a wide range of substrates, including even in vivo. Some of the advantages of the process are a) researchers have full control over the patterns to be created; b) it is a true direct-print process with no material removing steps involved; c) it is highly consistent and repeatable; and d) it is highly efficient and cost-effective. This paper will first give a detailed description of the CAB tool. Then, it will present a detailed process for printing polycaprolactone (PCL) into a defined 3D printing architecture, where the primary focus for these constructs is for use in human tissue engineering applications. Finally, mechanical characterization results of the printed scaffolds will be included in the paper.