The potential of surface nano-engineering in characteristics of cobalt-based nanoparticles and biointerface interaction with prokaryotic and human cells

Bringing resistance modulation to methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) strains using a quaternary ammonium compound coupled with zinc oxide nanoparticles

Nowadays, there are concerns about the inadequacy of new antimicrobials and the rise of antimicrobial resistance. Hence, novel antibacterial agents need to be discovered. In this respect, the use of nanoparticles (NPs) seems promising. Zinc oxide nanoparticles (ZnONPs) are functional and inexpensive NPs that possess antimicrobial characteristics, stability, microbial selectivity, and an easy manufacturing procedure. Imidazolium is one of the quaternary ammonium compounds (QACs) frequently employed as antimicrobial materials in industrial and clinical fields. The present study successfully employed imidazolium to couple with ZnONPs to improve their antimicrobial properties. The antimicrobial activities of ZnONPs doped with imidazolium (IM@ZnONPs) compared to ZnONPs and zinc (Zn) ions against some pathogen microorganism species including Streptococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Candida albicans (C. albicans) were evaluated by the microdilution method. The minimum inhibitory concentration (MIC) results revealed that the antimicrobial activities of Zn ions, ZnONPs, and IM@ZnONPs were concentration-dependent. Moreover, we found that the nanoparticulate forms of Zn had considerably stronger antibacterial activities, particularly against VRE and MRSA, compared to Zn ions which failed to restrain the microbial strains at the tested microdilutions of this experiment (MIC: ≥512 µg/mL). Interestingly, the incorporation of imidazolium into ZnONPs resulted in significant inhibition of microbial growth in antimicrobial-resistant pathogens at low concentrations (MIC: 32 µg/mL) and effectively improved the monodispersity of the final coated NPs in terms of size and morphology. To sum up, IM@ZnONPs can be a favorable substitute for conventional antimicrobial agents to combat antimicrobial resistance in many fields, including pharmaceuticals, dental materials, and cosmetic products.

Influence of Lanthanum Doping on the Photocatalytic and Antibacterial Capacities of Mg0.33Ni0.33Co0.33Fe2O4 Nanoparticles

The increase in environmental pollution, especially water pollution, has intensified the requirement for new strategies for the treatment of water sources. Furthermore, the improved properties of nano-ferrites permit their usage in wastewater treatment. In this regard, novel Mg0.33Ni0.33Co0.33LaxFe2−xO4 nanoparticles (NPs), where 0.00≤x≤0.08, were synthesized to test their photocatalytic, antibacterial and antibiofilm activities. The structural and optical properties of the prepared NPs were investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy and photoluminescence (PL) analysis. As La content increases, the bandgap energy increases, whereas the particle size decreases. The photocatalytic activity of the prepared NPs is evaluated by the degradation of methylene blue (MB) dye under sunlight irradiation. Superior activity is exhibited by Mg0.33Ni0.33Co0.33La0.01Fe1.99O4 NPs. The influence of catalyst dosage, pH, temperature and addition of graphene (Gr) on the photodegradation reaction was studied. Increasing the pH and temperature improved the rate of the photodegradation reaction. The antibacterial and antibiofilm activities of the NPs were assessed against Escherichia coli, Leclercia adecarboxylata, Staphylococcus aureus and Enterococcus faecium. Mg0.33Ni0.33Co0.33Fe2O4 NPs inhibited bacterial growth. They had bacteriostatic activity on all isolates, with a greater effect on Gram-positive bacteria. All tested nano-ferrites had significant antibiofilm activities against some biofilms.

Advances of Cobalt Nanomaterials as Anti-Infection Agents, Drug Carriers, and Immunomodulators for Potential Infectious Disease Treatment

Infectious diseases remain the most serious public health issue, which requires the development of more effective strategies for infectious control. As a kind of ultra-trace element, cobalt is essential to the metabolism of different organisms. In recent decades, nanotechnology has attracted increasing attention worldwide due to its wide application in different areas, including medicine. Based on the important biological roles of cobalt, cobalt nanomaterials have recently been widely developed for their attractive biomedical applications. With advantages such as low costs in preparation, hypotoxicity, photothermal conversion abilities, and high drug loading ability, cobalt nanomaterials have been proven to show promising potential in anticancer and anti-infection treatment. In this review, we summarize the characters of cobalt nanomaterials, followed by the advances in their biological functions and mechanisms. More importantly, we emphatically discuss the potential of cobalt nanomaterials as anti-infectious agents, drug carriers, and immunomodulators for anti-infection treatments, which might be helpful to facilitate progress in future research of anti-infection therapy.