University Honors

Macrophages are innate immune cells responsible for engulfing foreign material and clearing damaged cells. They naturally migrate toward sites of inflammation, making them attractive candidates for targeted payload delivery. They also release exosomes, nanosized (30-150 nm) extracellular vesicles (EVs) of endosomal origin that retain key molecular features of their parent cell and protect selected cargo from premature degradation. Exosomes have emerged as versatile delivery vehicles across wound healing, inflammation, regeneration, and the blood-brain barrier. Indocyanine Green (ICG) is a near-infrared dye widely used in medical imaging and photothermal therapies but is limited by its half-life of ~3-5 minutes. Macrophages and their exosomes may enhance ICG circulation time and delivery. However, low exosome yield and ex vivo stability remain barriers to translational application of macrophage-derived exosomes. In this study, we established a reproducible macrophage exosome isolation protocol and confirmed particle size within the expected range using Dynamic Light Scattering and Scanning Electron Microscopy. Furthermore, to address the challenge of long-term exosome storage, we are investigating the incorporation of cytoplasmic abundant heat soluble (CAHS) proteins known to stabilize cellular structures under extreme conditions. Preliminary UV-Vis spectroscopy data has demonstrated the presence of CAHS protein within exosomes following macrophage CAHS expression, suggesting successful incorporation. This study aims to optimize ICG loading into macrophage-derived exosomes while also addressing exosome stability and storage. By refining loading strategies and CAHS-mediated preservation, these experiments seek to enhance the longevity, functionality, and translational potential of exosome-based delivery systems for imaging and therapeutic applications.