近日，英国牛津大学的Philipp Kukura及其研究小组取得一项新进展。经过不懈努力，他们实现单一蛋白质光学全息术。相关研究成果已于2024年3月13日在国际知名学术期刊《自然—光子学》上发表。
该研究团队成功展示了基于暗场散射显微镜的非共光路几何方法，其灵敏度与马赫-曾德尔干涉仪相当。研究人员巧妙地将散射光和参考光分离至四个平行的、固有相位稳定的检测通道中，从而在散射截面方面的灵敏度相比最先进的全息方法提升了五个数量级。他们进一步演示了对质量低于100kDa的单一蛋白质的检测，实现了高分辨率和质量测量。此外，通过分振幅和相位测量，研究团队还获得了关于样品身份以及单一生物分子极化的实验确定的直接信息。
据悉，纳米物体的光散射特性主要由其散射截面和极化率决定，是物理性质的基础所在。在过去的十年中，许多研究通过展示感兴趣的物体与参考场散射之间的干涉成像，证实了单分子灵敏度的可行性。由于图像对比度与分子极化率呈线性关系，这种方法使得溶液中单个生物分子的质量测量成为了可能。然而，目前所有的实践都是基于共光路干涉仪，这种技术无法独立地分离和调整参考光场与散射光场，从而限制了访问全息成像所提供的丰富工具箱的可能性。
附：英文原文
Title: Single-protein optical holography
Author: Thiele, Jan Christoph, Pfitzner, Emanuel, Kukura, Philipp
Issue&Volume: 2024-03-13
Abstract: Light scattering by nanoscale objects is a fundamental physical property defined by their scattering cross-section and thus polarizability. Over the past decade, a number of studies have demonstrated single-molecule sensitivity by imaging the interference between scattering from the object of interest and a reference field. This approach has enabled mass measurement of single biomolecules in solution owing to the linear scaling of image contrast with molecular polarizability. Nevertheless, all implementations so far are based on a common-path interferometer and cannot separate and independently tune the reference and scattered light fields, thereby prohibiting access to the rich toolbox available to holographic imaging. Here we demonstrate comparable sensitivity using a non-common-path geometry based on a dark-field scattering microscope, similar to a Mach–Zehnder interferometer. We separate the scattering and reference light into four parallel, inherently phase-stable detection channels, delivering a five orders of magnitude boost in sensitivity in terms of scattering cross-section over state-of-the-art holographic methods. We demonstrate the detection, resolution and mass measurement of single proteins with mass below 100kDa. Separate amplitude and phase measurements also yield direct information on sample identity and experimental determination of the polarizability of single biomolecules.
DOI: 10.1038/s41566-024-01405-2
Source: https://www.nature.com/articles/s41566-024-01405-2