Identification of macrophage polarization phenotypes in agarose matrix using metasurface-based terahertz biosensor of quasi-bound state continuum

Abstract

Rapid and noninvasive detection of macrophage polarization can facilitate the acquisition of crucial information for pre- and post-evaluation in cancer immunotherapy, unraveling tumor immune escape mechanisms and discovering drugs. Herein, we demonstrate an approach to identify macrophage polarization using the metasurface-based terahertz biosensor of quasi-bound state in the continuum. Non-polarized macrophages (M0) are driven into a pro-inflammatory phenotype (M1) or an anti-inflammatory phenotype (M2) in response to lipopolysaccharide or interleukin-4 stimulation. It is found that the M1 macrophages result in a slight resonance frequency blueshift, while the M2 results in an obvious resonance frequency blueshift as well as a broader resonance linewidth. The permittivity change reveals the aforementioned frequency change. Flow cytometry and gene expression measurements reveal distinct differences of phenotypes between M1 and M2 polarizations, consistent with the results of terahertz biosensing. Our results manifest a cost-effective approach for detecting macrophage polarization status and their functional activations, which holds significant implications for clinical and cellular immunology research.