It is a well-known fact that silver nanoparticles and their
composites show greater catalytic activities in the area of dye
reduction and their removal. Kundu et al. studied the reduction
of methylene blue by arsine in the presence of silver nanoparticle
[70]. Mallick et al. studied the catalytic activity of these
nanoparticles on the reduction of phenosafranine dye [71]. In
this study, the application of silver nanoparticles as an antimicrobial
agent was also investigated by growing E. coli on agar
plates and in liquid LB medium, both supplemented with silver
nanoparticles [72]. Single silver nanoparticles were applied to
investigate membrane transport in living microbial cells (P.
aeruginosa) in real times [73]. The triangular silver nanoparticles
fabricated by nanosphere lithography indeed function as
sensitive and selective nanoscale affinity biosensors. These
nanosensors retain all of the other desirable features of
Surface Plasmon Resonance (SPR) spectroscopy which is the
fundamental principle behind many colour based biosensor
applications and by changing nanoparticles size and shape,
these nanosensors possess at least two unique characteristics:
(i) modest refractive sensitivity and (ii) a short-range, sensing
length scale determined by the characteristic decay length of
the local electromagnetic field. These two factors combine to
yield an area of mass sensitivity of 100–1000 pg/mm2, which
is only a factor of 100 poorer than the best propagating SPR
sensitivities