Nitric Oxide-Releasing Tubular Polymersomes toward Advanced Gas Therapeutic Carriers.

Nitric oxide (NO) not only plays a vital role in a series of physiological processes but also has great potential for therapeutic applications. One of the existing challenges in using NO as a gas therapeutic is the inconvenience of gaseous NO storage, and thus, it is of importance to develop NO-releasing vehicle platforms. Although a variety of polymer-based NO-releasing nanoparticles have been constructed, a majority of the systems are limited to spherical morphologies. Here we present the preparation of biodegradable NO-releasing amphiphilic block copolymers containing poly(ethylene glycol) (PEG) and poly(trimethylene carbonate-4-nitro-3-(trifluoromethyl)) (PTMC-NF), which can self-assemble into tubular polymersomes. The tubular polymersomes with high aspect ratio structures showed much faster NO-releasing behavior, in contrast to their spherical counterparts under light irradiation. We found that the amount of NO released from tubular polymersomes is 1.5 times that from spherical polymersomes. More importantly, the tubular polymersomes have an enhanced anticancer performance compared to spherical polymersomes, demonstrating that the morphology of the NO-releasing polymersomes has a significant effect on their anticancer ability. In view of the benefits of NO-releasing tubular polymersomes, we expect that they can be used as an efficient NO delivery system for enhanced gas therapy.