Nano-immobilized flumequine with preserved antibacterial efficacy

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 191; p. 111019
• Main Authors: Bortoletti, Martina, Molinari, Simone, Fasolato, Luca, Ugolotti, Juri, Tolosi, Roberta, Venerando, Andrea, Radaelli, Giuseppe, Bertotto, Daniela, De Liguoro, Marco, Salviulo, Gabriella, Zboril, Radek, Vianello, Fabio, Magro, Massimiliano
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2020
• Subjects: Aeromonas veronii; Aeromonas veronii - drug effects; Animals; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Daphnia - drug effects; Daphnia - microbiology; Daphnia magna; Flumequine; Fluoroquinolones; Fluoroquinolones - chemistry; Fluoroquinolones - pharmacology; Iron oxide nanoparticles; Magnetite Nanoparticles - chemistry; Microbial Sensitivity Tests; Molecular Structure; Nanoantibiotics; Fluoroquinolones; EGA-MS; Aeromonas veronii; SAMNs; Iron oxide nanoparticles; Flumequine; FT-IR; Nanoantibiotics; TEM; Daphnia magna; ATR; TGA
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2020.111019

[Display omitted] •Flumequine was nano-immobilized of by self-assembly on iron oxide nanoparticles.•Antimicrobial efficacy of the antibiotic against Aeromonas veronii was preserved.•Crucial role of solvent exposed fluorine atom of flumequine was hypothesized.•Therapeutic effect of immobilized flumequine was proved on Daphnia magna.•The magnetic recoverable nanoantibiotic can be proposed for aquaculture. Flumequine was nano-immobilized by self-assembly on iron oxide nanoparticles, called surface active maghemite nanoparticles (SAMNs). The binding process was studied and the resulting core-shell nanocarrier (SAMN@FLU) was structurally characterized evidencing a firmly immobilized organic canopy on which the fluorine atom of the antibiotic was exposed to the solvent. The antibiotic efficacy of the SAMN@FLU nanocarrier was tested on a fish pathogenic bacterium (Aeromonas veronii), a flumequine sensitive strain, in comparison to soluble flumequine and the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were assessed. Noteworthy, the MIC and MBC of soluble and nanoparticle bound drug were superimposable. Moreover, the interactions between SAMN@FLU nanocarrrier and microorganism were studied by transmission electron microscopy evidencing the ability of the complex to disrupt the bacterial wall. Finally, a preliminary in vivo test was provided using Daphnia magna as animal model. SAMN@FLU was able to protect the crustacean from the fatal consequences of a bacterial infection and showed no sign of toxicity. Thus, in contrast with the strength of the interaction, nano-immobilized FLU displayed a fully preserved antimicrobial activity suggesting the crucial role of fluorine in the drug mechanism of action. Besides the importance for potential applications in aquaculture, the present study contributes to the nascent field of nanoantibiotics.