Speaker
Description
Near-infrared (NIR) optoacoustic (OptA) contrast agents are still dominated by synthetic organic and inorganic materials. Although these agents can generate strong signals, their broader preclinical and clinical use is often limited by concerns over toxicity, poor biocompatibility, and high manufacturing cost. Extracellular vesicles (EVs) offer a promising alternative because they are naturally derived, biocompatible, can be produced in bulk, and exhibit low immunogenicity. Most reported EVs-based contrast agents, however, are developed by loading them with synthetic dyes or nanoparticles, which may compromise vesicle integrity, reduce targeting performance, and introduce batch-to-batch variability. In this study, we present a fully biological strategy for optoacoustic imaging by developing genetically modified EVs (GM-EVs) from bioengineered mammalian cells. These vesicles are simple to produce and purify, cost-effective, and show strong optoacoustic performance from deep tissue. We further incorporated RVG peptides to support blood-brain barrier crossing after intravenous administration. In a murine brain tumour model, GM-EVs enabled clear tumour visualisation following systemic delivery, likely due to enhanced tumour accumulation. Importantly, the vesicles were well tolerated in vivo, supporting their potential as bioinspired, bioengineered, and biocompatible NIR optoacoustic contrast agents for in vivo imaging.