Comparison of clonogenic and PrestoBlue assay for radiobiological assessment of radiosensitization effects by bismuth oxide nanorods

Abstract Bismuth nanoparticle was developed and has been used in medicine for treatment enhancement. Due to their properties such as small size, long circulation in the body, and biocompatible to human body, bismuth nanoparticles have been used as radiosensitizer to enhance the effect of radiotherapy. In order to evaluate the effect of radiosensitizer, radiobiology has been utilized to understand the mechanisms of action of ionizing radiation. Clonogenic method has always been used to assess the relationship between cell survival and radiation dose via linear quadratic model. Because clonogenic assay take longer time to yield results, colorimetric assay such as PrestoBlue were introduced to obtain results in a faster and more sensitive way in measuring radiosensitivity. In this study, the cytotoxicity of bismuth oxide nanorods (Bi2O3-NR) synthesized with different size using hydrothermal method has been tested against cervical cancer cells (HeLa cells). Three different sizes of Bi2O3-NR, 70 nm, 80 nm and 90 nm, were used to compare between clonogenic and PrestoBlue using linear quadratic model and dose enhancement factor (DEF) in evaluating radiosensitizer effects. This study found that clonogenic assay, compared to PrestoBlue, resulted in more significant survival fraction. The DEF show different value, but the both assays demonstrated that the Bi2O3-NR size 90 nm produced higher radiosensitivity compared to Bi2O3-NR size 70 and 80 nm..