期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：52
DOI：10.1073/pnas.2113694118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Macrophage plasticity and activation dynamics are under intense investigation because their full complexity cannot be captured by the few predefined markers that are commonly used. Macrophages are highly adherent and respond to surface microstructures in a sensitive manner. Here, we use Raman microspectroscopy and Raman imaging to study the macrophage response to defined activation stimuli and transfer these findings to macrophages cultured on titanium with varying surface roughness. We show that Raman-based methods can discriminate between macrophage phenotypes noninvasively and without the need to use antibody-based cell markers.
Biomaterial characteristics such as surface topographies have been shown to modulate macrophage phenotypes. The standard methodologies to measure macrophage response to biomaterials are marker-based and invasive. Raman microspectroscopy (RM) is a marker-independent, noninvasive technology that allows the analysis of living cells without the need for staining or processing. In the present study, we analyzed human monocyte-derived macrophages (MDMs) using RM, revealing that macrophage activation by lipopolysaccharides (LPS), interferons (IFN), or cytokines can be identified by lipid composition, which significantly differs in M0 (resting), M1 (IFN-γ/LPS), M2a (IL-4/IL-13), and M2c (IL-10) MDMs. To identify the impact of a biomaterial on MDM phenotype and polarization, we cultured macrophages on titanium disks with varying surface topographies and analyzed the adherent MDMs with RM. We detected surface topography–induced changes in MDM biochemistry and lipid composition that were not shown by less sensitive standard methods such as cytokine expression or surface antigen analysis. Our data suggest that RM may enable a more precise classification of macrophage activation and biomaterial–macrophage interaction.
