为进行极低频电磁场生物效应及其机制的动态研究,研制了一种实时电磁场细胞暴露系统。该系统由细胞暴露工作台、电磁场细胞暴露仪、荧光显微镜、CCD摄像头、摄像头操作系统、荧光图像处理系统和电脑等组成。细胞暴露工作台上放置一个C形电磁铁芯,细胞皿放置在C形电磁铁芯的细胞槽中。采用CCD摄像头及其操作系统连续采集细胞荧光图像并生成图像集。通过荧光图像处理系统将图像集中目标细胞的荧光亮度转换为时间序列荧光数据值,以实现像线转换。最后电磁场暴露并同步检测活性氧自由基(ROS)、Ca^2+、线粒体膜电位(MMP)荧光的飞升特性。结果表明:该系统产生的磁感应强度在0.01-25.37 m T内可调,其绝对误差〈5%;磁场频率在0-340 Hz内可调,其绝对误差〈2%;传感器电压在1-200 m V内可调;灵敏度在0.011-0.127内可调;其线性度〈1.566%,精度〈2.694%。因此,所研制的仪器具有较高的线性度和精度。此外,在像线转换中研发的细胞定位、细胞识别、荧光测算、曲线校正等一系列技术可以满足电磁生物效应的实时检测需求。
For studying the biological effects of extremely low frequency electromagnetic fields(ELF-EMF) and their mechanisms, a real-time cell exposure system is developed. The system is composed of a cell hold platform, an EMF exposure apparatus, a fluorescence microscope, a CCD camera and its operating system, fluorescence image processing software, and computer. Cell dish is placed in the slot of a C-shaped electromagnet core on the cell hold platform. Using the CCD camera, cell images are acquired continuously and an image set of cell fluorescence is obtained. Then images of target cell in the image set is converted into a curve of fluorescence intensive by time series on cell by fluorescence image processing software. In this way, the soaring feature curves of reactive oxygen species(ROS), Ca^2+, mitochondrial membrane potential(MMP) of cells under ELF-EMF exposure are detected. The results showed that the system generates magnetic field with induction intensity of 0.01-25.37 m T(with error less than 5%), frequency of 0-340 Hz(with error less than 2%), and with sensor's working voltage within 1-200 m V, the system works with sensitivity of 0.011-0.127, linearity 〈1.566%, and accuracy〈 2.694%. These indexes indicate the high linearity and accuracy of the system. Combining with additional functions in the image-curve conversion, including cell location and reorganisation, fluorescence intensity detection, and curve correction, the system is able to detect the biological effects of EMF in real time.