DEVELOPMENT OF A HYBRID 3D PRINTING STRATEGY FOR NIPPLE RECONSTRUCTION

Abstract

Breast cancer and its most radical treatment, the mastectomy, significantly impose both physical transformations and emotional pain in thousands of women across the globe. Although reconstructive surgery is viewed as a possible recovery route for a lost symmetry and gender identity, it provides these patients with a breast mound whose most notable feature is scarring from the initial invasive procedure. Restoring the appearance of a nipple-areola complex directly on the breast represents an important psychological healing experience for these women and remains an unresolved clinical challenge, as current restorative techniques using Skin Flap Suturing (SFS) renders a flattened disfigured skin tab within a single year and requires subsequent surgeries. A tissue-engineered scaffold designed to integrate with the breast skin can not only aid in the development of a more robust and aesthetically pleasing nipple but can also aid in minimizing the patients’ prominent mastectomy scars. As 3D printing has become a popular and advantageous way to produce scaffolds with complex, patient-specific structures, this technology holds great promise for the fabrication of custom shaped nipple-areola grafts per any breast size. The work presented here is aimed at the development of a hybrid scaffold, composed of complementary biodegradable and synthetic hydrogels, that fosters the regeneration of a viable dermal layer in the form of a nipple-areola complex. The first aim of this research defined a dynamic dual bioink 3D printing strategy to produce soft tissue grafts that allow for enhanced host integration and volume retention. A new shape analysis technique utilizing CloudCompare software was also demonstrated to expand our available toolbox for assessing scaffold aesthetic properties. We then extended both modular printing and shape assessment techniques to the fabrication of a nipple-areola scaffold in the second aim, where both structural and bioactive components of the design were further adjusted. Lastly, the third aim explored the immune and vascular responses to these hybrid materials in a rigorous evaluation of an in vivo rat subcutaneous implantation study. Envisioned as subdermal implants, these nipple-areola bioprinted scaffolds have the potential to reduce subsequent surgical intervention by creating a lasting nipple-areola structure that harmoniously coexists with the patient’s breast skin. The proposed system can be applied to current breast reconstruction practices post patient healing of silicone implantation.