Congratulations! Achieved many firsts

The Shenzhou 15 astronaut crew recently used the space station two-photon microscope independently developed by my country to carry out an on-orbit verification experiment and achieved success. The reporter learned from the space station two-photon microscope project team on the 27th that this is the first time in the world that a two-photon microscope has been used to obtain three-dimensional images of the epidermis and superficial dermis of astronauts' skin during space flight, providing a new tool for future on-orbit health monitoring research of astronauts.

Two-photon microscopy is a nonlinear optical imaging technology based on two-photon absorption and fluorescence excitation, with the characteristics of high resolution, strong three-dimensional tomography, and large imaging depth. As the traditional two-photon microscope system is huge and cannot meet the stringent requirements of on-orbit experimental equipment for reliability, volume, weight, shock resistance, and vibration performance, the international community has not been able to achieve on-orbit operation and application of two-photon microscopy technology on the space station.

In 2017, Academician Cheng Heping, director of the National Center for Biomedical Imaging Sciences at Peking University, led a team to successfully develop a miniaturized two-photon microscope with a probe weighing only 2.2 grams, laying the foundation for the development of the space station two-photon microscope. In 2019, with the strong support of the China Manned Space Engineering Office, the team of Cheng Heping and Wang Aimin from Peking University, the team of Li Yingxian from the China Astronaut Research and Training Center, and the team of Feng Lishuang from the Beijing University of Aeronautics and Astronautics jointly established a space station two-photon microscope project team with Cheng Heping as the general leader. The project team overcame many technical difficulties in miniaturizing microscopes and successfully developed a space station two-photon microscope in September 2022.

The picture shows the imaging of the surface layer of astronauts' skin by the two-photon microscope in the space station (Photo provided by the research team)

Dr. Wang Junjie, a member of the project team and assistant researcher at the School of Future Technology of Peking University, introduced that on November 12, 2022, the space station two-photon microscope was successfully transported to the Chinese space station on the Tianzhou-5 cargo spacecraft, becoming the world's first two-photon microscope to enter space. Recently, the Shenzhou-15 astronaut crew completed the installation, debugging and first imaging test of the two-photon microscope, and successfully obtained in vivo two-photon microscopic images of the astronauts' face and forearm skin in orbit.

It is reported that the two-photon microscope on the space station can clearly present the three-dimensional distribution of the astronauts' skin structure and cells with submicron resolution, and has the ability to perform non-invasive microscopic imaging of the structure and components of the skin surface. The imaging results show that the three-dimensional structures of the skin, such as the stratum corneum, stratum granulosum, stratum spinosum, basal cell layer, and superficial dermis, are clearly discernible.

The picture shows the imaging of the surface layer of astronauts' skin by the two-photon microscope in the space station (Photo provided by the research team)

"The two-photon microscope on the space station is an important achievement that reflects the manufacturing level of high-end precision optical instruments in my country." Cheng Heping introduced that this on-orbit verification experiment achieved many firsts, such as the world's first normal operation of a two-photon microscope on orbit; the first normal operation of a femtosecond laser on orbit in China; and the first on-orbit observation of astronauts' cell structure and metabolic composition information. "These not only provide new tools and methods for conducting on-orbit health monitoring research on astronauts at the cellular and molecular levels, but also provide important technical means for conducting brain science research using the Chinese space station platform in the future."