Abstract
Antibiotic resistant bacteria not only affect human health and but also threatens the safety in hospitals and among communities. However, the emergence of drug resistant bacteria is inevitable due to evolutionary selection as a consequence of indiscriminate antibiotic usage. Therefore, it is necessary to develop a novel strategy by which pathogenic bacteria can be eliminated without triggering resistance. We propose a novel magnetic nanoparticle-based physical treatment against pathogenic bacteria, which blocks biofilm formation and kills bacteria. In this approach, multiple drug resistant Staphylococcus aureus USA300 and uropathogenic Escherichia coli CFT073 are trapped to the positively charged magnetic core-shell nanoparticles (MCSNPs) by electrostatic interaction. All the trapped bacteria can be completely killed within 30 min owing to the loss of membrane potential and dysfunction of membrane-associated complexes when exposed to the radiofrequency current. These results indicate that MCSNP-based physical treatment can be an alternative antibacterial strategy without leading to antibiotic resistance, and can be used for many purposes including environmental and therapeutic applications.
Highlights
multiple drug resistant bacteria (MDRB) will not be curable using these antibiotics
We elucidated that bacteria is killed due to the loss of membrane potential followed by dysfunction of membrane-associated complexes responsible for bacterial bioenergetics since magnetic core shell nanoparticles (MCSNPs) bound to bacterial cell surface adversely affects the membrane when it stimulated by RF
For the purpose of trapping bacteria and subsequent capturing of bacteria-MCSNPs complex using external magnetic field, we developed a paramagnetic iron oxide core coated with an aminated silica shell
Summary
For the purpose of trapping bacteria and subsequent capturing of bacteria-MCSNPs complex using external magnetic field, we developed a paramagnetic iron oxide core coated with an aminated silica shell. Significant reduction in biofilm thickness owing to the treatment with MCSNP is likely achieved due to the unavailability of free fimbriae required for the interaction with a surface for bacterial attachment Taken together, these results indicate that the MCSNP-trapped wild type UPEC possesses the cell surface analogy with the ∆fimA strain by having fimbriae buried inside MCSNP. Since MCSNP can closely pack on the bacterial surface (Fig. 2b), it is tempting to hypothesize that the MNP can mechanically perturb the cell membrane under a RF field This possibility was further investigated by measuring the outer membrane (OM) permeability of bacteria bound to MCSNPs using hydrophobic 1-N-phenylnaphthylamine (NPN) that shows fluorescence when it attaches to the phospholipid layer after passing through the outer membrane. This study could be a milestone as well as a cornerstone for the physical treatment of bacteria, and our new method may serve as an antibacterial alternative to chemical antibiotics
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