Maleylated-BSA-Coated Gold Nanopopcorns for Pulmonary Delivery of Quercetin

A non-motile bacterium, Mycobacterium tuberculosis (Mtb), causes tuberculosis (TB), an infection of the lower respiratory tract. Currently, rifampicin, isoniazid, ethambutol, and pyrazinamide are used as first-line treatment for drug-susceptible TB for two months, followed by four months of rifampicin and isoniazid. This treatment plan is linked to serious hepatic, dermatological, and hematopoietic adverse effects. The exploration of natural substances like quercetin for treating TB was driven by the significant side effects of the standard therapy protocol. Protein-coated gold nanopopcorns were developed as a dry-powder inhaler to deliver tailored medication to the lungs. The objective of this research article was to assess the effectiveness of quercetin-loaded gold nanopopcorns against Mtb H37Ra cells. The gold nanopopcorns prepared using the Turkevich method and subsequently coated with maleylated BSA (m-BSA) showed an adsorption efficiency of 87.02 ± 2.82%, particle size of 153.2 ± 26.45 nm, and a zeta potential of 29.3 ± 7.80 mV. In vitro release studies showed rapid initial release within 2 h, with a total drug release of 79.85 ± 1.33% over 24 h, with inhibition of 56.36% of H37Ra cells (IC50 = 2 μg/mL). These findings provide preliminary evidence for the potential of PNPs as a pulmonary quercetin delivery platform, warranting further evaluation in macrophage-based and tuberculosis disease models.