Correa Noemi, Harding Simon, Bailey Michelle, Brasselet Sophie, Palombo Francesca
School of Physics and Astronomy, University of Exeter, Stocker Road, EX4 4QL Exeter, UK.
Machine Intelligence Ltd, EX20 2JS South Zeal, UK.
Biomed Opt Express. 2019 Feb 19;10(3):1329-1338. doi: 10.1364/BOE.10.001329. eCollection 2019 Mar 1.
Brillouin spectroscopy is an emerging analytical tool in biomedical and biophysical sciences. It probes viscoelasticity through the propagation of thermally induced acoustic waves at gigahertz frequencies. Brillouin light scattering (BLS) measurements have traditionally been performed using multipass Fabry-Pérot interferometers, which have high contrast and resolution, however, as they are scanning spectrometers they often require long acquisition times in poorly scattering media. In the last decade, a new concept of Brillouin spectrometer has emerged, making use of highly angle-dispersive virtually imaged phase array (VIPA) etalons, which enable fast acquisition times for minimally turbid materials, when high contrast is not imperative. The ability to acquire Brillouin spectra rapidly, together with long term system stability, make this system a viable candidate for use in biomedical applications, especially to probe live cells and tissues. While various methods are being developed to improve system contrast and speed, little work has been published discussing the details of imaging data analysis and spectral processing. Here we present a method that we developed for the automated retrieval of Brillouin line shape parameters from imaging data sets acquired with a dual-stage VIPA Brillouin microscope. We applied this method for the first time to BLS measurements of collagen gelatin hydrogels at different hydration levels and cross-linker concentrations. This work demonstrates that it is possible to obtain the relevant information from Brillouin spectra using software for real-time high-accuracy analysis.
布里渊光谱学是生物医学和生物物理科学领域中一种新兴的分析工具。它通过千兆赫兹频率下热致声波的传播来探测粘弹性。传统上，布里渊光散射（BLS）测量是使用多程法布里 - 珀罗干涉仪进行的，这种干涉仪具有高对比度和分辨率，然而，由于它们是扫描光谱仪，在散射较弱的介质中通常需要较长的采集时间。在过去十年中，出现了一种新的布里渊光谱仪概念，它利用高角度色散的虚拟成像相控阵（VIPA）标准具，当对高对比度要求不高时，这种标准具能够实现对低浊度材料的快速采集。能够快速获取布里渊光谱，再加上系统的长期稳定性，使得该系统成为生物医学应用中的一个可行候选方案，特别是用于探测活细胞和组织。虽然人们正在开发各种方法来提高系统的对比度和速度，但很少有关于成像数据分析和光谱处理细节的研究发表。在这里，我们展示了一种我们开发的方法，用于从用双级VIPA布里渊显微镜采集的成像数据集中自动检索布里渊线形参数。我们首次将此方法应用于不同水合水平和交联剂浓度的胶原明胶水凝胶的BLS测量。这项工作表明，使用软件进行实时高精度分析，从布里渊光谱中获取相关信息是可行的。
