A cellular nitric oxide sensor based on porous hollow fiber with flow-through configuration

Nitric oxide plays important transmission and regulation roles in the human body, but its in-vitro concentration is extremely low with a short half-life. In this work, we developed a three-dimensional 'flow-through' configuration based on polysulfone hollow fiber (PHF) for efficient detection of cell released NO. The PHF served as the substrate for cell culture as well as the base layer of the working electrode. The carbon nanotubes-gold nanoparticles (CNT-AuNPs) composites uniformly wrapped around the PHF as the sensing layer. The CNT provided a large specific surface area, which allowed uniform distribution and high loading of AuNPs, thus enhancing the electrocatalytic activity synergistically. Compared with the conventional flow-by configuration, such configuration resulted in a higher surface area per unit volume and enhanced NO molecule capture efficiency. The CNT-AuNPs PHF sensor showed a low detection limit (91 nM), high stability, selectivity, and biocompatibility. We utilized it for real-time in-situ detection of NO released by human lung cancer cell H1299 under drug stimulation. Furthermore, owing to the unique PHF structure, we performed long-term monitoring of NO release under the treatment of Lipopolysaccharide, Nitroglycerin and Aminoguanidine, which helps to understand the kinetic process of cellular drug response.