Abstract:
Designing biomaterials and substrates possessing antibacterial
properties is a growing field nowadays. In this context, we have
developed benzimidazolium ionic liquids ILs-1(a−d)-based metal hybrid
nanocomposites using various metals such as silver (Ag), gold (Au), and
copper (Cu), which were fully characterized by various techniques. Their
morphology, elemental composition, crystallinity, and size were studied by
scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy,
powder X-ray diffraction, and dynamic light scattering, respectively.
Further, the prepared ionic liquids ILs-1(a−d) and ionic liquid@metal
composites were screened for their antibacterial potential against Grampositive
and Gram-negative pathogenic microorganisms via the colony
forming unit assay, and their minimum inhibitory concentrations (MICs)
were also evaluated. The results obtained from preliminary antibacterial
screening demonstrated that these ionic liquid@metal nanocomposites IL-
1d@M (M = Ag, Cu, and Au) exhibited potent antibacterial activity in comparison to the ionic liquids ILs-1(a−d). In particular, the
ionic liquid@silver nanocomposites (IL-1d@Ag) showed the most potent activity against both E. coli and S. aureus bacterial strains
with MIC = 12 ± 2 and 08 ± 2 μg/mL, respectively. The mechanism of action for antibacterial activity of IL-1d@Ag
nanocomposites was investigated through generation of 1O2 (ROS), whereas the morphology of treated pathogenic bacteria was
examined through atomic force microscopy and SEM. Furthermore, to utilize this developed material IL-1d@Ag in biomedical
applications, the prepared ionic liquid material was fabricated onto a microstructured aluminum (Al) substrate with hierarchically
arranged functionalities, and the modified surface was characterized and also evaluated for antibacterial activity. Moreover, the
hydrophobicity of the material coated onto the Al substrate was also measured by static water contact angle measurement, which
reveals its improved hydrophobic character. Thus, the developed hierarchical hydrophobic coating material possessing long-term
antibacterial activity on an Al substrate may minimize the wetting by biological secretions and also prevent the substrate from
corrosion.
