Path planning and topology optimization for biomimetic three-dimensional bioprinting

Official URL: http://risc01.sabanciuniv.edu/record=b1589819 (Table of Contents)

Tissue engineering is a highly promising multi-disciplinary field for development of biological substitutes to replace or enhance the functions of damaged tissue or organs. Traditionally, highly porous scaffolds have been used for most of the tissue engineering applications. However, the challenges in seeding the cells into a scaffold and possible immunogenic reactions of scaffold materials have led to a new method of bioprinting with live cells. With the recent advancement in bio-additive manufacturing, cells with or without biological active molecules and biomaterials can be bioprinted layer-by-layer to form three-dimensional (3D) tissue constructs. In this research work, novel biomodeling and path planning methods for bioprinting are proposed so three-dimensional tissue structures could be biomimetically printed with live cells directly from medical images. First, the medical images of the targeted tissue are imaged and segmented to convert computer tomography (CT) or magnetic resonance imaging (MRI) images to a mesh model. For path planning and optimization, the generated mesh models need to be converted to computer-aided (CAD) models. The captured mesh models are converted into smooth parametric surfaces by developed novel biomodeling algorithms. Then, several bioprinting strategies are proposed to bioprint live multi-cellular aggregates using the created computer models. Because mechanically weak cellular aggregates need to be supported perfectly at each layer, several support structure generation algorithms are proposed. The proposed methods are used to make bioprinted cellular aggregates conserve their planned 3D form, while providing sufficient conditions for cell fusion. The proposed algorithms are implemented and several example tissue structures are bioprinted by directly controlling a bioprinter with the generated commands. The results show that multicellular aggregates and their support structures can be bioprinted biomimetically in the form of the biomodeled tissues.