Scaled Production, Dose-Sparing Immunogenicity, and Biodistribution of Short Carbon Nanotubes as mRNA Vaccine Delivery Vehicles

Abstract Clinical translation of carbon nanotube (CNT)-based biomedical technologies requires a comprehensive understanding of scalable manufacturing, in vivo behavior, and dose efficiency. Here, we investigate NanoVac, a vaccine delivery platform based on functionalized short carbon nanotubes (SCNTs). We achieved scalable production and purification of NanoVac using tangential flow filtration (TFF), providing a reproducible process compatible with future Good Manufacturing Practice (GMP) development. To characterize its in vivo properties, we radiolabeled NanoVac with 89Zr via deferoxamine (DFO) chelation and evaluated it using longitudinal positron emission tomography (PET) imaging. After intramuscular administration in mice, NanoVac showed prolonged retention at the injection site, limited systemic distribution, and minimal accumulation in major organs, including the liver and spleen. NanoVac-associated radioactivity was gradually eliminated through renal and biliary excretion pathways over a 7-day observation period. Compared with other nonlipid nanocarriers, including polymeric nanoparticles and inorganic systems that often face challenges related to biodegradability, toxicity, or large-scale manufacturing, NanoVac combines scalable production with favorable biodistribution and retention characteristics. Immunogenicity studies demonstrated that NanoVac-mediated delivery of HIV-1 trimer-encoding mRNA achieved robust antibody responses at substantially reduced mRNA doses, with low-dose formulations (0.1–1 μg/animal) producing responses comparable to those observed with a 30 μg dose. In addition, NanoVac alone stimulated T-cell responses, supporting its potential role as both a delivery vehicle and an immune-modulating component. These findings establish the manufacturing feasibility, pharmacokinetic profile, and dose-sparing potential of NanoVac, thereby supporting its further development as a scalable vaccine delivery platform for rapid-response applications.