Injectable Peptide-Based Biomaterials for Cell Delivery

Abstract

Keratoconus is a progressive degenerative corneal disease characterized by stromal thinning and ectasia, often leading to significant visual impairment. Injectable biomaterials offer a promising minimally invasive alternative to corneal transplantation by reinforcing stromal structure and delivering therapeutic agents directly to the site of damage. This thesis focuses on the development, optimization, and characterization of collagen-like peptide (CLP)-based hydrogel microspheres as a platform for cell encapsulation and delivery in Keratoconus treatment. Building on previous work that demonstrated the efficacy of CLPs in forming on-the-spot hydrogels for tissue repair, this study adapts the formulation to a microfluidic platform for generating monodisperse microspheres suitable for cell delivery. A library of CLP sequences was screened with some sequences optimized to fit the current applications. C30 collagen-like peptide emerged as the optimal candidate due to its biocompatibility, gelation properties, and consistent microsphere formation. Microfluidic encapsulation parameters were optimized to ensure uniform sphere morphology and high cell viability. Live/dead assays demonstrated sustained viability of encapsulated GFP+ fibroblast cells over 72 hours, with C30 microspheres outperforming agarose controls in long-term cell survival. Scanning electron microscopy and pore size distribution analysis confirmed a porous architecture suitable for nutrient and waste exchange. Additional physicochemical characterizations, including circular dichroism, differential scanning calorimetry, rheology, and infrared spectroscopy, validated the structural stability and peptide nature of the materials. Together, these findings highlight the potential of CLP-based microspheres as a novel injectable platform for targeted and biocompatible therapeutic delivery to the cornea, supporting future development of minimally invasive regenerative treatments for Keratoconus.