ENGINEERING THE MICROENVIRONMENT TO MODULATE MACROPHAGE POLARIZATION AND ANTI-TUMOR ACTIVITY

The extracellular matrix (ECM) is a key regulator of immune cell function, influencing not only adhesion and migration but also macrophage activation and polarization. In this context, in vitro platforms that mimic ECM properties offer valuable tools to study immune modulation in pathological conditions such as cancer and chronic inflammation. In this study, we investigated how ECM-like substrates modulate macrophage polarization in response to nanomaterial-based inflammatory stimuli. We developed scaffolds composed of denatured collagen (gelatin) functionalized with increasing concentrations of carbon nanotubes (CNTs), used as model pro-inflammatory fibers. Human THP-1-derived macrophage-like cells were cultured on these substrates for up to five days. Cell viability remained unaffected after 24 hours, while morphological changes emerged at higher CNT concentrations and prolonged exposure, indicating a shift in activation state. The evaluation of macrophage immunological polarization using DCF staining and flow cytometry suggest polarization toward a pro-inflammatory M1 phenotype. To assess the functional consequences of macrophage activation in this model, we collected conditioned media from THP-1 cells exposed to CNT-containing substrates and evaluated their effect on tumor spheroid growth. Conditioned media from these macrophages significantly reduced the growth and size of glioblastoma spheroids, suggesting the release of anti-tumoral factors. Altogether, our results demonstrate that ECM-mimicking substrates functionalized with CNTs can modulate macrophage polarization toward an M1 phenotype. This platform provides a promising in vitro tool for investigating nanomaterial–immune system interactions and may support the development of novel immunomodulatory strategies in cancer therapy.