Talita de Francesco Calheiros

Topic

Synthesis and Characterization of Gold Nanoparticle-Loaded Block Copolymer Vectors for Biomedical Applications

Department of Chemistry

Date & location

• Wednesday, August 13, 2025
• 2:00 P.M.
• Elliott Building, Room 226

Examining Committee

Supervisory Committee

• Dr. Matthew Moffitt, Department of Chemistry, University of Victoria (Supervisor)
• Dr. Alexandre Brolo, Department of Chemistry, UVic (Member)
• Dr. Magdalena Bazalova-Carter, Department of Physics and Astronomy, UVic (Outside Member)

External Examiner

• Prof. Zhihong Nie, Department of Macromolecular Science, Fudan University

Chair of Oral Examination

• Dr. Kurt Smith, School of Exercise Science, Physical and Health Education, UVic

Abstract

Gold nanoparticles (GNPs) are widely studied in cancer therapy for their ability to enhance the effects of radiation and their potential as contrast agents for imaging. In this work, we developed and refined a polymeric self-assembly strategy using amphiphilic block copolymers to encapsulate gold nanoparticles. We focused on improving the system by reducing the amount of polymer required and systematically tuning parameters such as water content, polymer composition, and gold-to-polymer ratios to maximize gold loading while maintaining colloidal stability. These optimizations allowed us to increase the number of gold nanoparticles per micelle and study the potential as a contrast agent for computed tomography.

Building on this optimized system, we investigated the impact of gold loading on radiosensitization by studying DNA damage in cancer cells exposed to radiation. We also studied the impact of improved average of gold per polymeric vector smaller than 50 nm in multiple cell lines. Using the γH2AX assay, although some variability was observed across different regions of the samples, the overall trend suggested that higher gold content within the micelles may be associated with increased DNA damage. However, in most cases, the differences between the gold-treated samples and the control were not statistically significant, emphasizing the complexity of the system and the need for further studies to confirm these preliminary observations.

In the final part of this work, we explored the co-encapsulation of gold nanoparticles and the chemotherapeutic agent paclitaxel within the same polymeric micelles. We evaluated the cytotoxicity and apoptosis in cells treated with these dual-loaded nanoparticles, both with and without radiation exposure. The combination of gold and paclitaxel showed a synergistic effect, improving therapeutic outcomes of apoptosis compared to individual treatments.