“Insights into Macrophage-Nanoparticle Interactions: Exploring Polarization and Senescence Dynamics” - Henry Lee, BioNanomaterials

Engineered nanoparticles (NPs) are increasingly used in medical and environmental contexts, making it essential to understand their effects on immune cells, particularly macrophages.1 These versatile cells play a key role in recognizing, internalizing, and processing NPs, and their behavior can vary depending on their environment and activation state.
In the first project, we explored how macrophage phenotypes, specifically pro-inflammatory M1 and anti-inflammatory M2 states, influence their interactions with gold nanoparticles (AuNPs).2 The study uses techniques, including focused ion beam-scanning electron microscopy (FIB-SEM), revealing phenotype-dependent differences in NPs uptake and cell-to-cell variability. These findings emphasize the need to consider phenotypic diversity and single-cell heterogeneity in NPs design and applications.

Macrophages can also acquire other identities, including senescence, associated with aging and stress.3 In the second project, we studied how different NPs, including gold (Au), silica (SiO₂), and nanoplastic polyethylene terephthalate (PET), influence macrophage senescence over 10 days. We observed material-specific effects, with AuNPs promoting inflammation, SiO₂ NPs showing minimal impact, and PET NPs altering senescence pathways.

Together, these studies illustrate the complex interplay between NPs and macrophages, shedding light on phenotype-specific interactions and senescence, with implications for designing safer and more effective NPs-based applications.

“Modes with extremely long lifetimes in plasmonic double networks” - Cédric Schumacher, Soft Matter Physics

Fully connected metallic networks are known to prohibit the propagation of electromagnetic (EM) waves below a material-specific optical frequency called its plasma frequency. An interesting phenomenon occurs when multiple interwoven metallic networks are embedded into the same volume without touching. In such a configuration, EM modes exist below the plasma frequency and down to arbitrarily low frequencies. These EM modes behave fundamentally differently from light in natural materials and defy conventional wisdom.

In this talk, I will investigate the nature of these low-frequency modes. Their existence is probed through a microwave experiment where a finite slab of this plasmonic double network material is used as a resonator. I will discuss discrepancies between the established theory and our observation regarding the slab structure's chosen termination plane and explain the origin of these discrepancies.