Metallic Nanoparticles for Biomedical Applications
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Fig. 18 Synthesis of Ag NPs using endophytic bacterium; a UV-Vis absorption spectrum along
with its schematic illustration of synthesis procedure. A plant Coriandrum sativum, B extracting
endophytic bacterium, C cell-free supernatant, D AgNO 3 and Ag NPs. The colour change in the
solution confirms synthesis. b TEM and c SEM image of synthesized particles. Republished with
permission of the Royal Society of Chemistry, from Ref. [95]
3.4.2 Nanoparticle Synthesis Using Bacteria
Ag, Au, Pd, and Pt NPs have been successfully synthesized with the help of bacteria.
The commonly employed bacteria are Lactobacillus species, Klebsiella pneumonia,
Enterobacter coacoae, and Bacillus species for producing Ag NPs, Rhodococcus
species for Au, and E. Coli. for Pd, Pt, and Ag NPs. Due to the ability to adjust in
the environment and its abundance in nature, prokaryotes are getting more attention
in MNPs synthesis. Productivity is less compared to fungi since bacteria secrets less
amount of protein compared to fungi [34]. Spherical shaped Ag NPs were synthesized
from endophytic bacterium Bacillus siamensis strain C1 extracted from the plant
Coriandrum sativum. Figure 18 shows the characterization of Ag NPs synthesized
using endophytic bacterium. The absorbance peak of AgNO 3 is 300 nm, while Ag
NPs possess a plasmonic peak at 409 nm after incubating NPs for 24 h at 30 °C.
TEM and SEM analysis revealed that synthesized particles are spherical with an
average diameter of 34 ± 3 nm [95]. For the bacteria-based synthesis of Pt NPs,
the hydrogenase enzyme extracted from sulphate-reducing bacteria was used. It has
been reported that spherical Pt NPs were synthesized by the bioreduction mechanism
from Desulfovibrio vulgaris. At the same time, cuboidal shapes were obtained by
enzymatic reduction of extracts from Acinetobacter calcoaceticus in intracellular
based synthesis. Further, it has been employed as a reduction pathway to synthesize
intracellular Pt NPs from the periplasmic membrane [96].
3.4.3 Nanoparticle Synthesis Using Plant Products
MNPs such as Au, Ag, Pt, Cu, and Zn can be easily synthesized with the help of
plant extracts. Usually, in plants, primary and secondary metabolites are involved
in redox reactions associated with plant metabolism. This property is utilized in the
65
Fig. 18 Synthesis of Ag NPs using endophytic bacterium; a UV-Vis absorption spectrum along
with its schematic illustration of synthesis procedure. A plant Coriandrum sativum, B extracting
endophytic bacterium, C cell-free supernatant, D AgNO 3 and Ag NPs. The colour change in the
solution confirms synthesis. b TEM and c SEM image of synthesized particles. Republished with
permission of the Royal Society of Chemistry, from Ref. [95]
3.4.2 Nanoparticle Synthesis Using Bacteria
Ag, Au, Pd, and Pt NPs have been successfully synthesized with the help of bacteria.
The commonly employed bacteria are Lactobacillus species, Klebsiella pneumonia,
Enterobacter coacoae, and Bacillus species for producing Ag NPs, Rhodococcus
species for Au, and E. Coli. for Pd, Pt, and Ag NPs. Due to the ability to adjust in
the environment and its abundance in nature, prokaryotes are getting more attention
in MNPs synthesis. Productivity is less compared to fungi since bacteria secrets less
amount of protein compared to fungi [34]. Spherical shaped Ag NPs were synthesized
from endophytic bacterium Bacillus siamensis strain C1 extracted from the plant
Coriandrum sativum. Figure 18 shows the characterization of Ag NPs synthesized
using endophytic bacterium. The absorbance peak of AgNO 3 is 300 nm, while Ag
NPs possess a plasmonic peak at 409 nm after incubating NPs for 24 h at 30 °C.
TEM and SEM analysis revealed that synthesized particles are spherical with an
average diameter of 34 ± 3 nm [95]. For the bacteria-based synthesis of Pt NPs,
the hydrogenase enzyme extracted from sulphate-reducing bacteria was used. It has
been reported that spherical Pt NPs were synthesized by the bioreduction mechanism
from Desulfovibrio vulgaris. At the same time, cuboidal shapes were obtained by
enzymatic reduction of extracts from Acinetobacter calcoaceticus in intracellular
based synthesis. Further, it has been employed as a reduction pathway to synthesize
intracellular Pt NPs from the periplasmic membrane [96].
3.4.3 Nanoparticle Synthesis Using Plant Products
MNPs such as Au, Ag, Pt, Cu, and Zn can be easily synthesized with the help of
plant extracts. Usually, in plants, primary and secondary metabolites are involved
in redox reactions associated with plant metabolism. This property is utilized in the