Wide-field linear structured illumination microscopy (LSIM) extends resolution beyond the diffraction limit by moving unresolvable high-frequency information into the passband of the microscopy in the form of moiré fringes. However, due to the diffraction limit, the spatial frequency of the structured illumination pattern cannot be larger than the microscopy cutoff frequency, which results in a twofold resolution improvement over wide-field microscopes. This Letter presents a novel approach in point-scanning LSIM, aimed at achieving higher-resolution improvement by combining stimulated emission depletion (STED) with point-scanning structured illumination microscopy (psSIM) (STED-psSIM). The according structured illumination pattern whose frequency exceeds the microscopy cutoff frequency is produced by scanning the focus of the sinusoidally modulated excitation beam of STED microscopy. The experimental results showed a 1.58-fold resolution improvement over conventional STED microscopy with the same depletion laser power.

脂滴是真核细胞中必不可少的一种球形细胞器，与很多细胞生理学过程息息相关。荧光成像技术是观察研究脂滴最有力的工具之一。受光学衍射极限的限制，传统的宽场以及共聚焦显微镜所能达到的成像分辨率约为250 nm左右，这对于观测小脂滴，尤其是新生脂滴（尺寸约30~60 nm）来说是远远不够的。在这种情况下，近年来新兴的各种能够打破衍射极限的超分辨荧光显微镜（如受激发射损耗显微镜、结构光照明显微镜以及光激活定位显微镜等）逐渐吸引了科研人员的兴趣。为了得到高分辨率脂滴荧光图像，除了上述超分辨显微镜之外，还需要具有与之相匹配的高性能荧光探针。本文将简要介绍这几种超分辨显微镜的工作原理，讨论其对荧光探针光物理性质的特殊要求，并进一步系统总结脂滴超分辨成像荧光探针的研究进展。与此同时，本文将分析对比不同超分辨显微镜在脂滴荧光成像方面的优势与不足，并对其发展趋势进行展望。

观察细胞器间动态相互作用，深入分析作用规律，对于揭示生理病理过程现象背后的机制具有十分重要的意义。传统光学显微镜受到由光波波长和孔径造成的衍射极限的限制，无法观测细胞器纳米级精细结构及细胞器间相互作用的动态变化规律。超分辨显微成像技术的出现为细胞器相互作用研究提供了重要手段，在深入揭示细胞器相互作用规律，阐明生理病理现象深层的机制研究中发挥了重要的作用。文中介绍了受激发射损耗（Stimulated emission depletion, STED）显微成像、结构光照明显微成像（Structured illumination microscopy, SIM）、单分子定位显微成像（Single molecule localization microscopy, SMLM）技术，并总结了这三类超分辨显微成像技术在细胞器相互作用中的应用与现状，为超分辨显微成像技术在细胞器相互作用研究中的应用提供思路拓展。最后，对超分辨显微成像技术在细胞器相互作用研究中的优势与不足进行分析总结，展望了超分辨显微成像技术在活细胞内细胞器相互作用成像中的需求发展趋势，为光学与医学及生物学的交叉融合发展提供一定的参考。

A stimulated emission depletion is capable of breaking the diffraction limit by exciting fluorescent molecules with a solid Gaussian beam and quenching the excited molecules with another donut beam through stimulated emission. The coincidence degree of these two beams in three dimensions will significantly influence the spatial resolution of the microscope. However, the conventional alignment approach based on raster scanning of gold nanoparticles by the two laser beams separately suffers from a mismatch between fluorescence and scattering modes. To circumvent the above problems, we demonstrate a fast alignment design by scanning the second beam over the fabricated sample, which is made of aggregation-induced emission (AIE) dye resin. The relative positions of solid and donut laser beams can be represented by the fluorescent AIE from the labeled spots in the dye resin. This design achieves ultra-high resolutions of 22 nm in the x/y relative displacement and 27 nm in the z relative displacement for fast spatial matching of the two laser beams. This study has potential applications in scenarios that require the spatial matching of multiple laser beams, and the field of views of different objectives, for example, in a microscope with high precision.

鉴于双光子受激发射损耗（STED）复合显微镜在神经疾病临床诊断及脑科学研究中的重要作用，对双光子STED复合显微成像中多波长选通、多光束合束、关键技术指标等进行了研究，完成了复合显微镜样机系统集成研制和复合成像。该复合显微镜可以对荧光标记的样本进行扫描成像，具备红绿双色荧光扫描成像功能、双光子绿色荧光成像功能和STED超分辨绿色荧光成像功能。测试结果表明，该复合显微镜成像深度达到700 μm，分辨率优于60 nm。