High-speed and large-scaled light-sheet microscopy with electrically tunable lens

Abstract

Fluorescence microscopic imaging technology realizes specific imaging by labeling biological tissue with fluorescence molecules, which has a high signal-to-noise ratio and has been widely used in the field of medical biology research. Some typical fluorescence microscopy techniques, such as confocal microscopy and two-photon microscopy, have high fluorescence intensity, but the long exposure can cause phototoxicity and photobleaching of biological tissue, which is difficult to meet the demand for long-time observation or noninvasive imaging. Then, light sheet fluorescence microscopy (LSFM) has become a hot research topic in fluorescence micro-imaging in recent years due to its fast speed, high resolution, low photobleaching and low phototoxicity. The imaging speed of a typical light sheet microscopy is not fast enough to observe fast biological activities such as transmission of neural signals, blood flow, and heart beats. At present, many reported light-sheet fluorescence microscopies still have some problems such as fixed imaging surface, slow imaging speed, small imaging depth or residual artifacts. Therefore, in this paper, a rapid light-sheet fluorescence microscopy based on electrically tunable lens is built. To achieve the rapid movement of the focal plane of the detection objective lens, the electrically tunable lens is introduced to meet the reqirement for fast changing of the diopter. Similarly, the rapid movement of light sheet is achieved by introducing one-dimensional galvanometer to change the rotation angle. Fast imaging requires the light sheet and focal plane to overlap in real time, which is then combined with a high-speed sCMOS receiving fluorescence to complete the whole imaging. In the experiment, the vertical depth significantly increases by modifying the optical path, and the LABVIEW programming is used to coordinate and improve the dynamic imaging quality, which effectively reduces the artifacts generated in rapid imaging. Finally, an imaging speed of 275 frames/s with a lateral resolution of ~0.73 μm, vertical resolution of ~5.5 μm, and an imaging depth of ~138 μm is achieved. This is of significance for developing the real-time and non-invasive imaging of living biological tissues.