Development of Fluorometric Gamma Dosimeter Based on BODIPY-LMG Dye Loaded Superporous Polymer

Abstract

Accurate, easy to use and low-cost gamma (γ) dosimeters are indispensable in gamma irradiation facilities for measuring absorbed dose. Available γ-dosimeters and detectors have various limitations which restrict their uses in practical applications. Here, we developed a first of its kind solid supported fluorometric gamma dosimeter. For this, BODIPY-leucomalachite green dye conjugate (BLMG) was designed and synthesized which showed colorimetric (yellow to green) and “Off-On” fluorescence changes under gamma exposure in chloroform solution. This allowed precise measurement of low dose gamma radiation. Interestingly, dose range and sensitivity can be changed by optimising dye concentrations which is beneficial for its application in different gamma irradiation facilities. Detailed mechanistic studies were also done to confirm the photoinduced electron transfer (PET) based sensing mechanism. Further, based on this principle, a solid supported dosimeter was developed. As a solid support, superporous polyHEMA matrix was used which was grafted with polyGMA via high energy radiation (γ-radiation) assisted mutual irradiation grafting method to enhance its chloroform absorbing and holding capability. Then, the chloroform solution of BLMG dye was absorbed in this superporous matrix and used for the dosimetric studies which showed both colorimetric (yellow to green) as well as ratiometric fluorescence changes upon gamma exposure. The blue fluorescence of the solid matrix changed to bright green fluorescence under gamma irradiation condition. This fluorescence colour change was quantified which showed linear changes in blue and green component of the fluorescence light. This linear response was useful to quantify the gamma doses (5-45 Gy) accurately. The newly developed solid-supported dosimeter will be highly useful for commercial application in blood irradiation facility due to its simple detection procedure, low cost and accurate measurement.