Chemophotothermal Combined Therapy with 5- Fluorouracil and Branched Gold Nanoshell Hyperthermia Induced Reduction in Tumor Size in a Xenograft Colon Cancer Model

This study evaluated the antitumor efficacy of combined chemo photothermal therapy with 5-fluorouracil (5-FU) and branched gold nanoshells (BGNSs) in a colorectal cancer model. BGNSs were synthesized via a seed-mediated method and characterized via electron microscopy and UV‒vis spectroscopy, revealing an average diameter of 126.3 nm and a plasmon resonance peak at 800 nm, which are suitable for near-infrared (NIR) photothermal applications. In vitro assays using SW620-GFP colon cancer cells demonstrated a ≥90% reduction in cell viability after 24 hours of combined treatment with 5-FU and BGNS under NIR irradiation. In vivo, xenograft-bearing nude mice received weekly intratumoral administrations of the combined therapy for four weeks. The tumor volume was significantly lower in the combination group than in the control and mono-therapy groups, with nearly complete tumor regression observed. Thermographic imaging con-firmed that localized hyperthermia reached 45°C at the tumor site. These findings suggest a strong synergistic effect between 5-FU- and BGNS-mediated hyperthermia, suggesting a promising strategy for enhancing therapeutic outcomes in patients with colorectal cancer while potentially minimizing systemic toxicity. This study highlights the potential of integrating nanotechnology and conventional chemotherapy for more effective and targeted cancer treatment.