Radiosensitivity enhancement of bismuth-based nanoparticles in radiotherapy: A systematic review and meta-analysis

Nano-biomaterials facilitate targeted drug delivery and serve as radio-sensitizers, reducing therapeutic doses and side effects while enhancing efficacy. This meta-analysis aims to investigate the impact of bismuth-based nanoparticles on enhancing radiosensitivity, specifically by evaluating the dose enhancement factor (DEF) in radiotherapy.

This systematic review and meta-analysis evaluated the radiosensitizing effect of bismuth-based nanoparticles. PubMed, Web of Science, and Scopus were searched for eligible studies. The cumulative dose enhancement factor (DEF) was assessed, and subgroup and sensitivity analyses were performed to investigate the effect of nanoparticle size and concentration on radiosensitization.

The average dose enhancement factor (DEF) for bismuth concentrations < 50 and ≥ 50 was not statistically different (1.41 vs. 1.47; p > 0.05). This indicates that bismuth concentrations above 50 are not more effective against tumor cells. In contrast, the mean DEF for tumor sizes < 10 and > 10 was 1.21 and 1.51, respectively (P = 0.02). Nanoparticle size significantly influenced radiosensitization, with particles larger than 10 nm producing higher DEF values compared with smaller particles. In contrast, increasing nanoparticle concentration did not lead to a proportional increase in DEF, suggesting possible biological saturation or toxicity effects.

These findings suggest increasing nanoparticle concentration above 50 µg/mL did not further enhance the radiosensitizing effect against tumor cells. Nanoparticle size significantly influences the dose enhancement factor, with larger (>10 nm) nanoparticles yielding higher DEF values. This highlights the importance of optimizing nanoparticle size to improve radiosensitization in tumor treatment. Our results indicate that bismuth-based nanoparticles enhance radiation effects and may serve as promising radiosensitizers in preclinical models.