Mesoporous silica nanoparticles containing silver as novel antimycobacterial agents against Mycobacterium tuberculosis

Abstract

Tuberculosis remains today a major public health issue with a total of 9 million new cases and 2 million deaths annually. The lack of an effective vaccine and the increasing emergence of new strains of Mycobacterium tuberculosis (Mtb) highly resistant to antibiotics, anticipate a complicated scenario in the near future. The use of nanoparticles features as an alternative to antibiotics in tackling this problem due to their potential effectiveness in resistant bacterial strains. In this context, silver nanoparticles have demonstrated high bactericidal efficacy, although their use is limited by their relatively high toxicity, which calls for the design of nanocarriers that allow silver based nanoparticles to be safely delivered to the target cells or tissues. In this work mesoporous silica nanoparticles are used as carriers of silver based nanoparticles as antimycobacterial agent against Mtb. Two different synthetic approaches have been used to afford, on the one hand, a 2D hexagonal mesoporous silica nanosystem which contains silver bromide nanoparticles distributed all through the silica network and, on the other hand, a core@shell nanosystem with metallic silver nanoparticles as core and mesoporous silica shell in a radial mesoporous rearrangement. Both materials have demonstrated good antimycobacterial capacity in in vitro test using Mtb, being lower the minimum inhibitory concentration for the nanosystem which contains silver bromide.Therefore, the interaction of this material with the mycobacterial cell has been studied by cryo-electron microscopy, establishing a direct connection between the antimycobactericidal effect observed and the damage induced in the cell envelope.

Delivery by Dendritic Mesoporous Silica Nanoparticles Enhances the Antimicrobial Activity of a Napsin‐Derived Peptide Against Intracellular Mycobacterium tuberculosis

“…Several studies underline that MSN have a great potential as drug delivery system in tuberculosis therapy. [24][25][26][27] Regarding tuberculosis therapy with AMPs, Tenland et al could show that the encapsulation of the AMP NZX within MSN could enhance the antimicrobial activity against Mycobacterium bovis (BCG) in vitro and Mycobacterium tuberculosis H37Rv in vivo. [27] Dendritic mesoporous silica nanoparticles (DMSN) a subclass of MSN have been demonstrated to be excellent candidates for drug delivery due to good synthetic control over important particle characteristics, like particle and pore diameter, specific surface area, and pore volume.…”

Recent Advances Toward the Use of Mesoporous Silica Nanoparticles for the Treatment of Bacterial Infections

“…On a very recent contribution Montalvo-Quirós et al studied the different performance of both approaches reviewed so far: a core-shell structure in which a big AgNP is coated by a silica layer and model that grows AgNPs within the mesopores. 88 Both structures were prepared successfully and tested against M. tuberculosis . It was found that the approach onto AgNPs were grown at the mesopores had a higher antibiotic effect that could be assumed to be consequence of an increased dissolution rate of AgNPs together with a more intimate contact between particles and mycobacteria.…”

Challenge in the Discovery of New Drugs: Antimicrobial Peptides against WHO-List of Critical and High-Priority Bacteria

“…In recent decades, uncontrolled drug use has led to major public health, economic, and environmental problems. As a result, bacteria, as well as other microorganisms, have acquired or developed unfavorable resistance mechanisms toward conventional drugs [ 1 ]. The World Health Organization (WHO) has launched a priority list of bacteria that should be studied more rigorously, and all the bacteria on this list are resistant to various drugs [ 2 ].…”