Zhang Delong, Lan Lu, Bai Yeran, Majeed Hassaan, Kandel Mikhail E, Popescu Gabriel, Cheng Ji-Xin
1Department of Biomedical Engineering, Boston University, Boston, MA 02215 USA.
2Department of Physics, Zhejiang University, Hangzhou, 310028 China.
Light Sci Appl. 2019 Dec 11;8:116. doi: 10.1038/s41377-019-0224-0. eCollection 2019.
Phase-contrast microscopy converts the phase shift of light passing through a transparent specimen, e.g., a biological cell, into brightness variations in an image. This ability to observe structures without destructive fixation or staining has been widely utilized for applications in materials and life sciences. Despite these advantages, phase-contrast microscopy lacks the ability to reveal molecular information. To address this gap, we developed a bond-selective transient phase (BSTP) imaging technique that excites molecular vibrations by infrared light, resulting in a transient change in phase shift that can be detected by a diffraction phase microscope. By developing a time-gated pump-probe camera system, we demonstrate BSTP imaging of live cells at a 50 Hz frame rate with high spectral fidelity, sub-microsecond temporal resolution, and sub-micron spatial resolution. Our approach paves a new way for spectroscopic imaging investigation in biology and materials science.
相衬显微镜将穿过透明标本（如生物细胞）的光的相移转化为图像中的亮度变化。这种无需破坏性固定或染色就能观察结构的能力已在材料和生命科学领域得到广泛应用。尽管有这些优点，但相衬显微镜缺乏揭示分子信息的能力。为了弥补这一差距，我们开发了一种键选择性瞬态相（BSTP）成像技术，该技术通过红外光激发分子振动，导致相移的瞬态变化，可由衍射相显微镜检测到。通过开发一种时间选通泵浦-探测相机系统，我们展示了以50赫兹帧率对活细胞进行BSTP成像，具有高光谱保真度、亚微秒时间分辨率和亚微米空间分辨率。我们的方法为生物学和材料科学中的光谱成像研究开辟了一条新途径。
