Two ‐photon focal modulation microscopy for high‐resolution imaging in deep tissue

In this paper, by exploiting modulation and demodulation techniques, we demonstrate a two ‐photon focal modulation microscopy (2PFMM), which shows significant improvements in spatial resolution and imaging penetration depth. Besides, when applied in thick biological samples, 2PFMM can dramatically increase the signal‐to‐background ratio of the images at the depth between 300 and 50 0 μm, due to the enhanced background rejection capability. Two ‐photon microscopy (2PM) is one of the most widely used tools forin vivo deep tissue imaging. However, the spatial resolution and penetration depth are still limited due to the strong scattering background. Here we demonstrate a two ‐photon focal modulation microscopy. By utilizing the modulation and demodulation techniques, background rejection capability is enhanced, thus spatial resolution and imaging penetration depth are improved. Compared with 2PM, the transverse resolution is increased by 70%, while the axial resolutio n is increased to 2‐fold. Furthermore, when applied in conventional 2PM mode, it can achieve inertial‐free scanning in either transverse or axial direction with in principle unlimited scanning speed. Finally, we applied 2PFMM in thick scattering samples to further examine the imaging performance . The results show that the signal‐to‐background ratio of 2PFMM can be improved up to five times of 2PM at the depth of 500 μm. Fluorescent imaging in the mouse brain tissue. 3D Thy1‐GFP hippocampa...

Source: Journal of Biophotonics - November 7, 2018 Category: Physics Authors: Yao Zheng, Jiajia Chen, Xin Shi, Xinpei Zhu, Jiahao Wang, Limeng Huang, Ke Si, Colin J.R. Sheppard, Wei Gong Tags: FULL ARTICLE Source Type: research