Printing the future of skin

: A DoE-based methodological framework for developing and characterising bioinks for 3D bioprinting applications

Abstract

The formulation of robust, reproducible, and biologically supportive bioinks is fundamental to advancing the fields of tissue engineering. This thesis focuses on the systematic development and optimisation of a novel bioink designed specifically for the fabrication of full-thickness skin constructs via extrusion-based 3D bioprinting. The bioink was developed using a combination of sodium alginate, hyaluronic acid, and dextran-40, each selected for their complementary contributions to structural integrity, biological compatibility, and mimicking the dense extracellular matrix (ECM) environment of human skin. Human platelet lysate (HPL) was incorporated as a xeno-free supplement to replace fetal bovine serum (FBS), providing a humanised growth factor milieu to enhance cell viability, proliferation, and maturation. Rheological characterisation and a design of experiments (DoE) optimisation framework enabled fine-tuning of bioink formulation and bioprinting parameters, identifying 40 mM CaCl₂ with a 6-hour crosslinking period as optimal for achieving both mechanical stability and cytocompatibility.

The optimised bioink demonstrated favourable shear-thinning behaviour, shape fidelity post-printing, and supported high cell viability across multiple cell types, including primary keratinocytes, fibroblasts, and an epidermoid carcinoma cell line (A431). Comparative studies revealed that cells within 3D printed constructs exhibited enhanced proliferation, stratification, and extracellular matrix deposition compared to conventional 2D cultures. Furthermore, tumour cell integration into the constructs demonstrated that the bioink supports not only normal tissue architecture but also dynamic tumour– stroma interactions, an essential feature for cancer modelling applications.

In summary, this research establishes a reproducible and scalable bioink formulation tailored for skin tissue engineering, with potential extensions to other tissue types. By demonstrating a bioink capable of supporting both healthy and diseased cellular phenotypes within a humanised, xeno-free 3D environment, this thesis contributes significantly to the development of more accessible and clinically relevant platforms for future applications in personalised medicine, wound healing, and oncology research.

Date of Award	2026
Original language	English
Awarding Institution	Canterbury Christ Church University