Quantitative evaluation of radiation dose by γ-H2AX on a microfluidic chip in a miniature fluorescence cytometer

Evaluation of radiation dose is very important for the detection of radiation damage. gamma-H2AX is a popular biological dosimeter to evaluate the radiation effect. Typically, bulky and expensive commercial flow cytometers are used to detect gamma-H2AX. This paper presents a miniaturized and high sensitive cytometer using a microfluidic chip for evaluating the radiation dose by detecting the mean immunofluorescence intensity of gamma-H2AX. A compact optical focusing system and a shift-phase differential amplifier are designed to improve the detection sensitivity. Sample lymphocyte cells are stained by FITC fluorescent dye after being irradiated by UVC. Comparison experiments between the developed miniature cytometer and a commercial flow cytometer were conducted under different radiation doses. The developed microfluidic cytometer also demonstrates a good linear correlation between the measured fluorescence intensity and the irradiation dose with a detection limit similar to that of the commercial flow cytometer. The developed cytometer can evaluate quantitatively the radiation dose by the mean fluorescence intensity of gamma-H2AX with a significantly smaller amount of blood samples than a commercial flow cytometer. (C) 2014 Elsevier Ltd. All rights reserved.