155
oxide gets converted to the most damaging superoxide radical (O 2
−
) (Zhang et al.
2010). On the other hand, the reactive oxygen species generation due to ultrasonication has also been recently reported. Ultrasonic activated zinc oxide nanoparticles have the ability to split H 2 O into H
+
which further interacts with O 2 to generate
H 2 O 2 (Ansari et al. 2016). Thus, reactive oxygen species generation under the effect
of nanoparticles is an upcoming research area to study their cytotoxic activity
against drug-resistant microorganisms. Table 6.4 summarizes the mechanism of
action of different nanoparticles on drug-resistant bacteria.
6.4 Advances in Addressing Antimicrobial Resistance by
Nanoparticle-Mediated Approaches
The potential of nanoparticles in controlling the spread of multidrug-resistant bacteria has opened tremendous scope for their exploitation. Among the different types
of nanoparticles, silver nanoparticles have shown immense success in biomedical
applications (Chaloupka et al. 2010). Their mechanism for reducing the growth of
clinically relevant resistant strains has now been studied in detail. Other nanoparticles like those of titanium dioxide, iron oxide, and copper oxide have also been
studied for their antibacterial properties; however, certain drawbacks like colloidal
instability and aggregation problems have limited their usage in biological applications (Baalousha et al. 2008; Degabriel et al. 2018). Nevertheless, recent new
research is now focusing to modify nanoparticles by attaching functional groups or
other compounds like antibiotics to enhance their efficacy toward multidrugresistant bacteria. Some of these latest approaches are being discussed in the current
section.
(i) Modification of Carbon Nanotubes
Carbon nanotubes and their functionalized variants have been deemed to hold
great promise in the fight against multidrug-resistant bacterial infections (Maleki
Dizaj et al. 2015; Mocan et al. 2016). Surface modifications in carbon nanotubes
have yielded many desirable effects in the recent past. A study was conducted where
in multi-walled carbon nanotubes were synthesized modified with silver nanoparticles. These nanostructures were found to be quite effective against pathogens like
E. coli and S. aureus due to disruption in their membrane function leading to cell
death (Dinh et al. 2015). Similarly PEGylated silver-coated single-walled carbon
nanotubes were found to be effective in controlling the growth of food pathogen
Salmonella sp. (Chaudhari et al. 2015).
A recent study showed the antibacterial activity of functionalized single-walled
carbon nanotubes synthesized using herbal extracts of Hempedu bumi. These carbon nanotubes were potent against pathogenic bacteria like E. coli and Bacillus sp.
(Foo et al. 2018). Wang et al. (2017) showed that the modification of multi-walled
carbon nanotubes with OH, COOH, and NH 2 groups led to an increased antifungal
6 Exploring Microbial Nanotoxicity Against Drug Resistance in Bacteria
oxide gets converted to the most damaging superoxide radical (O 2
−
) (Zhang et al.
2010). On the other hand, the reactive oxygen species generation due to ultrasonication has also been recently reported. Ultrasonic activated zinc oxide nanoparticles have the ability to split H 2 O into H
+
which further interacts with O 2 to generate
H 2 O 2 (Ansari et al. 2016). Thus, reactive oxygen species generation under the effect
of nanoparticles is an upcoming research area to study their cytotoxic activity
against drug-resistant microorganisms. Table 6.4 summarizes the mechanism of
action of different nanoparticles on drug-resistant bacteria.
6.4 Advances in Addressing Antimicrobial Resistance by
Nanoparticle-Mediated Approaches
The potential of nanoparticles in controlling the spread of multidrug-resistant bacteria has opened tremendous scope for their exploitation. Among the different types
of nanoparticles, silver nanoparticles have shown immense success in biomedical
applications (Chaloupka et al. 2010). Their mechanism for reducing the growth of
clinically relevant resistant strains has now been studied in detail. Other nanoparticles like those of titanium dioxide, iron oxide, and copper oxide have also been
studied for their antibacterial properties; however, certain drawbacks like colloidal
instability and aggregation problems have limited their usage in biological applications (Baalousha et al. 2008; Degabriel et al. 2018). Nevertheless, recent new
research is now focusing to modify nanoparticles by attaching functional groups or
other compounds like antibiotics to enhance their efficacy toward multidrugresistant bacteria. Some of these latest approaches are being discussed in the current
section.
(i) Modification of Carbon Nanotubes
Carbon nanotubes and their functionalized variants have been deemed to hold
great promise in the fight against multidrug-resistant bacterial infections (Maleki
Dizaj et al. 2015; Mocan et al. 2016). Surface modifications in carbon nanotubes
have yielded many desirable effects in the recent past. A study was conducted where
in multi-walled carbon nanotubes were synthesized modified with silver nanoparticles. These nanostructures were found to be quite effective against pathogens like
E. coli and S. aureus due to disruption in their membrane function leading to cell
death (Dinh et al. 2015). Similarly PEGylated silver-coated single-walled carbon
nanotubes were found to be effective in controlling the growth of food pathogen
Salmonella sp. (Chaudhari et al. 2015).
A recent study showed the antibacterial activity of functionalized single-walled
carbon nanotubes synthesized using herbal extracts of Hempedu bumi. These carbon nanotubes were potent against pathogenic bacteria like E. coli and Bacillus sp.
(Foo et al. 2018). Wang et al. (2017) showed that the modification of multi-walled
carbon nanotubes with OH, COOH, and NH 2 groups led to an increased antifungal
6 Exploring Microbial Nanotoxicity Against Drug Resistance in Bacteria