Additive tissue manufacturing for breast reconstruction combining CAD CAM with adipose tissue engineering

ADDITIVE TISSUE MANUFACTURING FOR BREAST RECONSTRUCTION; COMBINING CAD/CAM WITH ADIPOSE TISSUE ENGINEERING Mohit Prashant Chhaya Bachelor of Biotechnology Innovation (Hons) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy School of Chemistry, Physics and Mechanical Engineering Science and Engineering Faculty Queensland University of Technology 2015 Keywords Additive manufacturing, melt extrusion, breast tissue engineering, composite scaffold, polycaprolactone, anatomically-shaped scaffolds, patient-specific scaffolds, large volume tissue engineering, animal models, finite element analysis, computer modelling Additive tissue manufacturing for breast reconstruction; combining cad/cam with adipose tissue engineering i Abstract Breast tissue engineering is an interdisciplinary field which combines expertise from engineering, cell biology, material science and plastic surgery primarily aiming to reconstruct breasts following a post-tumour mastectomy Since breast implants also have a cosmetic function, there are a variety of factors that need to be considered in order to achieve an ideal surgical and cosmetic outcome An off-the-shelf 3D printed macroporous scaffold therefore may be unnatural-looking and problematic for a large number of patients with unusual body shapes This thesis is therefore focused on fabricating scaffolds that can be tailored and customised for each individual patient As part of this PhD project, an integrated strategy was developed whereby image is first taken of the breast region of a mastectomy patient using medical imaging techniques such as 3D laser scanning, CT or MRI scans Software packages were then developed to process the captured images into a patient-specific 3D computeraided design (CAD) model which is then sent to a bioprinter to be fabricated in the form of a scaffold suitable for tissue engineering Concurrently, on the tissue culture side, tissue engineering strategies – precursor cell induction vs body-as-abioreactor approach were explored In the precursor cell induction strategy, patientspecific scaffolds were seeded with human umbilical cord perivascular cells and cultured under static conditions for weeks and subsequently weeks in a biaxial rotating bioreactor These tissue-engineered constructs were then seeded with Human Umbilical Vein Endothelial Cells and implanted subcutaneously into athymic nude rats for 24 weeks Angiogenesis and adipose tissue formation were observed throughout all constructs at all timepoints The percentage of adipose tissue compared to overall tissue area increased from 37.17% to 62.30% between week ii Additive tissue manufacturing for breast reconstruction; combining cad/cam with adipose tissue engineering and week 15 (p