Magnetically Driven Silver‐Coated Nanocoils for Efficient Bacterial Contact Killing

Abstract

The increasing threat of multidrug-resistant bacterial strains against conventional antibiotic therapies represents a significant worldwide health risk and intensifies the need for novel antibacterial treatments. In this work, an effective strategy to target and kill bacteria using silver-coated magnetic nanocoils is reported. The coil palladium (Pd) nanostructures are obtained by electrodeposition and selective dealloying, and subsequently coated with nickel (Ni) and silver (Ag) for magnetic manipulation and antibacterial properties, respectively. The efficiency of the nanocoils is tested in the treatment of Gram-negative Escherichia coli (E.coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA), both of which represent the leading multidrug-resistant bacterial pathogens. The nanocoils show highly effective bacterial killing activity at low concentrations and in relatively short durations of treatment time. Three different investigation techniques, LIVE/DEAD assay, Colony-Forming Unit (CFU) counting, and Scanning Electron Microscope (SEM), reveal that the antibacterial activity is a result of bacterial membrane damage caused by direct contact with the nanocoil. The low cytotoxicity towards fibroblast cells along with the capability of precise magnetic locomotion make the proposed nanocoil an ideal candidate to combat multidrug-resistant bacteria in the field of biomedical and environmental applications.

Dynamics of Novel Photoactive AgCl Microstars and Their Environmental Applications

“…In the present work, two environmental applications inherently related to the properties of AgCl were explored: I) degrading organic material such as certain pollutants through photocatalytic properties and II) antibacterial treatment with silver, which is widely known for its antibacterial properties. The benefit of antibacterial‐silver‐employing microswimmers has been recently demonstrated by Pané’s group with silver‐coated helical nanomachines . The photocatalytic activity of AgCl μS was evaluated with an aqueous solution of methyl orange (see Figure a–b).…”

“…Catalytic micromotors can be exceptional devices for environmental applications [14] by taking advantage of the spontaneous movement.I nt he presentw ork, two environmental applications inherently relatedt ot he properties of AgCl were explored: I) degradingo rganic material [15] such as certain pollutants [16] through photocatalytic properties and II) antibacterial treatment with silver,w hich is widely known fori ts antibacterial properties.T he benefit of antibacterial-silver-employing microswimmers has been recently demonstrated by PanØ's group with silver-coated helical nanomachines. [17] The photocatalytic activity of AgCl mSw as evaluated with an aqueous solution of methyl orange (see Figure 4a-b). Specifically,t wo different sol- The photocatalytic activity of AgCl mSw as evaluated by testing the photocatalytic degradation of methyl orange(MO) aqueouss olution.…”

Biohybrid and Bioinspired Magnetic Microswimmers

“…e) Contact killing of bacteria with silver‐coated helices (scale bar: 200 nm). Adapted with permission . Copyright 2015, John Wiley and Sons.…”

Silver Nanowires: Synthesis, Antibacterial Activity and Biomedical Applications

“…Silver nanospecies have been synthesized via a variety of different methods, resulting in the production of different configurations, each possessing a discrete extent of antibacterial activity. Commonly synthesized silver nanospecies include: silver nanowires, silver nanorods, silver nanocubes and silver nanospheres [10][11][12], as well as more recent silver nanocoils [13]. Due to their greater surface area to volume ratio, silver nanospecies offer enhanced characteristics compared to bulk silver [14][15][16], and may therefore serve as an additional weapon in our current antibacterial arsenal.…”