158
lines, the bactericidal activity of graphene nanosheets after functionalizing them
with silver has also been studied (Ma et al. 2011). The silver-functionalized graphene nanoparticles had significant antibacterial activity as compared to the activity
of silver and graphene nanoparticles alone. Likewise, graphene oxide nanoparticles
coated with gold have been found to inhibit a broad range of both Gram-positive and
Gram-negative bacteria with 100% efficiency (Hussain et al. 2014). Graphene oxide
nanoparticles have also been attempted to be modified by silane ligands for their
attachment to silver ions. These nanocomposites showed potent antibacterial activities against E. coli and S. aureus pathogens (Fathalipour and Mardi 2017).
(iv) Modifications of Dendrimers
Dendrimers are basically nanoscaled molecules with a radial symmetry. These
comprise a symmetrical core along with an inner and outer shell. The surface modification of dendrimers is performed to enhance their antibacterial activity towards
many antibiotic-resistant strains. Their antimicrobial activities depend on the size
and the nature of the attached functional group (Lind et al. 2015). For example,
polyamidoamine dendrimers were found to hold higher antibacterial activity when
this group was substituted with OH or COOH (Xue et al. 2015). Recent studies
show the development of dendrimeric peptides for the control of multidrug-resistant
strains having antibacterial, antifungal, and antiviral properties (Scorciapino et al.
2017). Phloroglucinol succinic acid dendrimers have also been synthesized with
anionic surfaces. Out of these some of the dendrimers were found to be quite potent
against S. aureus, E. coli, and human pathogen C. albicans (Kumar et al. 2015).
Choi et al. (2012) reported the potential use of a dendrimer-based vancomycin
nanoplatform as a targeting agent for a drug-resistant bacterial surface.
(v) Nanoparticle–Antimicrobial Peptide Conjugates
Antimicrobial peptides are potent antimicrobial agents produced by bacteria and
eukaryotes, and these peptides have been proven to be more potent than the conventional antibiotics used for controlling the spread of multidrug-resistant strains
(Nguyen et al. 2011). These antimicrobial peptides are broad-spectrum agents and
attack both Gram-positive and Gram-negative strains. Despite their potential activity, the antimicrobial peptides, however, suffer from being employed in therapeutics
due to their impermeability and low enzyme stability. Hence, the recent approaches
to increase the efficacy of antimicrobial peptides include their grafting on different
types of nanoparticles. While the antibacterial properties of nanoparticles have
been well established, their conjugation with antimicrobial peptides has led to the
development of a new and advanced technology in preventing the spread of antimicrobial resistance.
In the recent past, several studies on the potential role of antimicrobial peptide–
nanoparticle conjugates as antimicrobial agents against drug-resistant pathogens
have been documented. Of these, the most widely explored are antimicrobial
peptide- conjugated graphene oxide nanoparticles (Rajchakit and Sarojini 2017).
For example, in a recent study, gold nanoparticles conjugated with antimicrobial
peptides, esculentin-1a(1–21)NH 2 ,have shown promising results against the
R. Sinha et al.
lines, the bactericidal activity of graphene nanosheets after functionalizing them
with silver has also been studied (Ma et al. 2011). The silver-functionalized graphene nanoparticles had significant antibacterial activity as compared to the activity
of silver and graphene nanoparticles alone. Likewise, graphene oxide nanoparticles
coated with gold have been found to inhibit a broad range of both Gram-positive and
Gram-negative bacteria with 100% efficiency (Hussain et al. 2014). Graphene oxide
nanoparticles have also been attempted to be modified by silane ligands for their
attachment to silver ions. These nanocomposites showed potent antibacterial activities against E. coli and S. aureus pathogens (Fathalipour and Mardi 2017).
(iv) Modifications of Dendrimers
Dendrimers are basically nanoscaled molecules with a radial symmetry. These
comprise a symmetrical core along with an inner and outer shell. The surface modification of dendrimers is performed to enhance their antibacterial activity towards
many antibiotic-resistant strains. Their antimicrobial activities depend on the size
and the nature of the attached functional group (Lind et al. 2015). For example,
polyamidoamine dendrimers were found to hold higher antibacterial activity when
this group was substituted with OH or COOH (Xue et al. 2015). Recent studies
show the development of dendrimeric peptides for the control of multidrug-resistant
strains having antibacterial, antifungal, and antiviral properties (Scorciapino et al.
2017). Phloroglucinol succinic acid dendrimers have also been synthesized with
anionic surfaces. Out of these some of the dendrimers were found to be quite potent
against S. aureus, E. coli, and human pathogen C. albicans (Kumar et al. 2015).
Choi et al. (2012) reported the potential use of a dendrimer-based vancomycin
nanoplatform as a targeting agent for a drug-resistant bacterial surface.
(v) Nanoparticle–Antimicrobial Peptide Conjugates
Antimicrobial peptides are potent antimicrobial agents produced by bacteria and
eukaryotes, and these peptides have been proven to be more potent than the conventional antibiotics used for controlling the spread of multidrug-resistant strains
(Nguyen et al. 2011). These antimicrobial peptides are broad-spectrum agents and
attack both Gram-positive and Gram-negative strains. Despite their potential activity, the antimicrobial peptides, however, suffer from being employed in therapeutics
due to their impermeability and low enzyme stability. Hence, the recent approaches
to increase the efficacy of antimicrobial peptides include their grafting on different
types of nanoparticles. While the antibacterial properties of nanoparticles have
been well established, their conjugation with antimicrobial peptides has led to the
development of a new and advanced technology in preventing the spread of antimicrobial resistance.
In the recent past, several studies on the potential role of antimicrobial peptide–
nanoparticle conjugates as antimicrobial agents against drug-resistant pathogens
have been documented. Of these, the most widely explored are antimicrobial
peptide- conjugated graphene oxide nanoparticles (Rajchakit and Sarojini 2017).
For example, in a recent study, gold nanoparticles conjugated with antimicrobial
peptides, esculentin-1a(1–21)NH 2 ,have shown promising results against the
R. Sinha et al.