Measuring the complex mechanical properties of biological objects has become a necessity to answer key questions in mechanobiology and to propose innovative clinical and therapeutic strategies. In this context, Brillouin light scattering (BLS) has recently come into vogue, offering quantitative imaging of the mechanical properties without labels and with a micrometer resolution. In biological samples, the magnitude of the spectral changes are typically of a few tens of MHz, and the ability of modern spectrometers to monitor such subtle changes needs to be evaluated. Moreover, the multiplicity of variations in optical arrangements, specific to each lab, requires to set a standard for the assessment of the characteristics of BLS systems. In this paper we propose a protocol to evaluate the precision and accuracy of two commercial spectrometers that is reproducible across labs. For a meaningful comparison, we coupled the spectrometers to the same microscope and to the same laser. We first evaluated the optimum acquisition time and laser power. We evaluated the precision using pure water samples. We determined the accuracy by probing water solutions with increasing concentration of salt and comparing it with theory. Following these quantifications, we applied the VIPA-based spectrometer to tumor spheroids engineered from different cell lines that possess different metastatic potentials and resistance to therapies. On these models, we detected significant changes in the linewidth suggesting that BLS measurements of the viscosity could be used as a read-out to distinguish different levels of drug resistance.

中文翻译：

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评估商用虚拟成像相阵列和基于Fabry-Pérot的布里渊光谱仪在生物学中的应用

测量生物物体的复杂机械性能已经成为回答力学生物学关键问题并提出创新的临床和治疗策略的必要条件。在这种情况下，布里渊光散射（BLS）最近开始流行，它提供了机械特性的定量成像而无标签且具有千分尺分辨率。在生物样品中，光谱变化的幅度通常为几十MHz，因此需要评估现代光谱仪监测此类细微变化的能力。此外，针对每个实验室的光学装置的多种变化都需要为评估BLS系统的特性设定标准。在本文中，我们提出了一种协议，用于评估可在实验室之间重现的两种商用光谱仪的精度和准确性。为了进行有意义的比较，我们将光谱仪耦合到同一显微镜和同一激光器。我们首先评估了最佳采集时间和激光功率。我们使用纯净水样品评估了精度。我们通过探测盐浓度增加的水溶液并将其与理论进行比较来确定准确性。在完成这些量化之后，我们将基于VIPA的光谱仪应用于从具有不同转移潜能和对治疗的抵抗力的不同细胞系改造而来的肿瘤球体。在这些型号上