Enhanced antibacterial activity against multidrug-resistant Mycobacterium tuberculosis of nano‑silver prepared by Konjac glucomannan via asymmetric flow field-flow fractionation.

Enhancing the antibacterial activity of silver nanoparticles (AgNPs) against drug-resistant Mycobacterium tuberculosis remains an urgent need in the field of public health. In a previous study, we fabricated highly dispersible AgNPs using Konjac glucomannan (KGM), and the antibacterial activity of KGM-AgNPs against drug-resistant Mycobacterium tuberculosis did not meet the demand. In this study, we aimed to resolve the above problem by improving the homogeneity of KGM-AgNPs, using asymmetric flow field-flow fractionation (AF4) coupled with MALS, RI, UV, and a fraction collector. We obtained three fractions of KGM-AgNPs with high homogeneity, as evidenced by TEM, DLS, and Zeta-potential analyses, which demonstrated varying antibacterial activity against different drug-resistant Mycobacterium tuberculosis strains. Their antibacterial activity against Mycobacterium tuberculosis was closely related to their particle size, with smaller particles being more effective in killing multidrug-resistant strains. Overall, the antibacterial activity against drug-resistant Mycobacterium tuberculosis and homogeneity of silver nanoparticles could be significantly improved by AF4, which is crucial for their applications in life sciences and technology.