PhD Thesis Colloquium: Mr. Yusuf Olatunji Waidi (12/03/26)
Thesis title:
Vat-Based 3D Bioprinting of Advanced Biomaterials for Bone Tissue Engineering and Controlled Drug Release
Faculty advisor(s):
Prof. Kaushik Chatterjee
When?
12th March, 2026 (Thursday), 03:00 PM (India Standard Time)
Where
KPA Auditorium, Department of Materials Engineering
Abstract:
Sustained interest in bone tissue engineering (BTE) and controlled drug delivery emerges from the rising prevalence of critical-sized bone defects that exceed the body’s natural healing capacity. While autografts and allografts are current clinical standards, they are hampered by donor-site morbidity, immune rejection, and poor vascular integration. Similarly, systemic drug delivery often fails due to off-target effects and a lack of spatiotemporal control. This thesis investigates the rational design of photocurable biopolymers and composite bioinks for vat-based three-dimensional (3D) bioprinting, integrating osteogenic, osteoimmunomodulatory, angiogenic, antimicrobial, and stimuli-responsive drug delivery functions. The central hypothesis is that precise regulation of bioink chemistry and photopolymerization kinetics can enable multifunctional hydrogels that meet both structural and biological requirements for bone regeneration and on-demand therapeutic release.
Research objectives 1–3 of the thesis focus on the development of advanced bioinks for BTE to fabricate hydrogel scaffolds via visible-light (405 nm) vat-based 3D bioprinting. Initial efforts established photocurable silk fibroin-methacrylate (SFMA) and bacterial nanocellulose (BNC) composites, in which tailoring the BNC content (0-0.75 wt%) significantly enhanced mechanical stability and biomineralization. An optimized formulation (10% SFMA with 0.75% BNC) exhibited enhanced mechanical stability and interconnected porosity, supporting robust pre-osteoblast proliferation and biomineralization to fabricate hydrogel scaffolds, as evidenced by increased calcium deposition and osteogenic marker expression, thereby validating SFMA/BNC as a biomimetic scaffold platform. Building on this, the development of methacrylated levan (LeMA) scaffolds introduced an osteoimmunomodulatory dimension. The 15% LeMA promoted osteogenesis in MC3T3 pre-osteoblasts and activated RAW 264.7 macrophages, with the potential to direct macrophage polarization toward an anti-inflammatory M2-like phenotype. The third objective integrated antimicrobial and angiogenic functionalities by incorporating copper-modified mesoporous kaolin into a pectin-methacrylate/SFMA matrix. Resulting constructs exhibited broad-spectrum antibacterial activity against Gram-positive and Gram-negative strains, enhanced osteogenic differentiation of MC3T3 cells, and stimulated endothelial cell migration and tube formation, thereby integrating antimicrobial, angiogenic, and osteogenic functions within a single scaffold system.
In the fourth objective of the thesis, vat-based 3D printing of hydrogels was utilized to engineer stimuli-responsive therapeutic systems. Near-infrared (NIR)-responsive microneedle arrays were developed by embedding transition-metal dichalcogenide nanosheets within a polysaccharide and SFMA-based matrix. This hierarchical design enabled photothermal activation, allowing for externally triggered, localized drug release with high structural fidelity. By systematically evaluating photothermal conversion and release kinetics, this research bridges the gap between precision additive manufacturing and smart drug delivery.
Overall, this thesis provides a comprehensive toolkit of photocurable biomaterials for advanced tissue regeneration and smart delivery systems.