gradient pump (viz., homeostatic imbalance), respectively, being operated across the

bacterial cells. Disturbed physiochemical mechanisms ultimately lead to cell lysis

and triggered apoptosis (Hemeg 2017). Similar results were obtained with other

metallic nanoparticles as well (Chatterjee et al. 2014; Huo et al. 2016; Khashan et al.

2016; Sirelkhatim et al. 2015).

11.3.8 Cellular Envelope Permeation and Destabilization of Cellular

Organelles

An effective translocation and subcellular co-localization of NPs become a prereq-

uisite for attaining a significantly high level of cytotoxicity. However, the level of

cell lysis acts as a function of zeta potential (surface charge foliage) of the NPs

(Hemeg 2017). A study conducted by Lellouche et al. showed a promising applica-

tion of metallic nanoparticles in apprehending the biofilm formation around catheters

due to two bacterial strains, viz., E. coli and S. aureus (Lellouche et al. 2012b). In

their study, they engineered the surface of catheters with MgF-NPs. The results

displayed the significant antibacterial efficacy of the designed system. The surface

grafted NPs were able to restrict the bacterial colonization in a comprehensive

manner and offered long-lasting sterilization ability to the catheters (Lellouche

et al. 2012b). The charge foliage imparted on the corona of these particles allowed

them to permeate readily through the highly inaccessible cellular envelope of the

bacteria. Once the NPs are lodged inside the periphery of the cell, a sudden decrease

in cytoplasmic pH is observed. This drop in pH results in an escalation of the cellular

membrane permeability. Owing to this peroxidation of the lipidic bilayer, membrane

takes place, thus killing the bacterial colony (Hemeg 2017; Lellouche et al. 2012b).

In another study, Shamaila et al. synthesized gold nanoparticles, and the bacterial

killing propensity of these NPs was tested in enteric bacterial human pathogens, viz.,

E. coli, S. aureus, B. subtilis, and K. pneumoniae (Hemeg 2017; Shamaila et al.

2016). It was deciphered that the proposed nanoparticulate system was capable of

producing antibactericidal effects. It also came to light that the size and dose of the

NPs had an innate relationship with the cellular toxicity. The mode of action of these

particles was found to be the effective and deep-seated colocalization of these

moieties inside the cellular organelle, viz., ribosome. This translocation facilitated

the disorientation of the 30S ribosomal subunit because of which translation phe-

nomenon was interrupted and cell lysis took place (Hemeg 2017; Shamaila et al.

2016).

11.3.9 Bacterial Film Disruption

Certain biological entities generally called as quorum sensing molecules are pro-

duced during the maturation phase of bacterial biofilm growth. These molecules

chiefly comprise two major components, viz., matrix and carbohydrates (extracellu-

lar), which aids in establishing direct communication between the adjacent/

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Nanoparticles: A Potential Breakthrough in Counteracting. . .

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