Figure 1.
Molecular structure of biopolymer pectin and Raman analyte Nile Blue A.
Structure of (a) Nile blue A and (b) pectin.
Figure 2.
Silver nanoparticles characterization.
(a) UV-Vis absorbance spectrum, (b) TEM image (inset SAED pattern) and (c) size distribution histogram pattern of (i) A. indica Ag NPs and (ii) pectin Ag NPs.
Figure 3.
Surface composition of bio-silver nanoparticles.
FTIR spectra of (a) A. indica and (b) pectin Ag NPs.
Figure 4.
Colloidal stability of bio-silver nanoparticles in water.
(a) UV-Vis absorbance spectra, and (b) HDD and ζ potential values of A. indica Ag NPs. (c) UV-Vis absorbance spectra and (d) HDD and ζ potential values pectin Ag NPs.
Figure 5.
Colloidal stability of A. indica Ag NPs in different media.
Time dependent UV-Vis absorbance spectra and zeta (HDD and ζ potential value) measurements of A. indica Ag NPs dispersed in different media. A. indica Ag NPs dispersed in (a-b; e-f) NaCl, (c-d; g-h) NaNO3, (i-j; m-n) BSA, (k; o) pH 7 and (l; p) pH 9.
Figure 6.
Colloidal stability of pectin Ag NPs in different media.
Time dependent UV-Vis absorbance spectra and zeta (HDD and ζ potential value) measurements of pectin Ag NPs dispersed in different media. Pectin Ag NPs dispersed in (a-b; e-f) NaCl, (c-d; g-h) NaNO3, (i-j; m-n) BSA, (k; o) pH 7 and (l; p) pH 9.
Figure 7.
Optical enhancing properties of silver nanoparticles.
(a) SERS spectra of NBA adsorbed on A. indica Ag NPs, pectin Ag NPs and CRSC substrates. (b) Raman intensity count with respect to Ag substrates at 549 and 1642 cm-1.
Figure 8.
Effect of Ag NPs on bacterial growth.
Viability of E. coli cells in solid agar and NB liquid media on exposure to antibiotic (ampicillin) and Ag NPs. Percentage histogram plot of the number of E. coli colonies as a function of the concentration of (a) ampicillin, (b) A. indica Ag NPs and (c) pectin Ag NPs in agar plates. Growth curve of E. coli in NB medium supplemented with (d) ampicillin, (e) A. indica Ag NPs and (f) pectin Ag NPs.
Figure 9.
Electron microscopy images of bio-Ag NPs exposed E. coli cells.
SEM images of E. coli cells treated with (a-c) A. indica Ag NPs and (d-f) pectin Ag NPs. HRTEM images E. coli cells treated with (g-i) A. indica Ag NPs and (j-l) pectin Ag NPs.