Fig 1.
Characterization of AgNPs synthesized in EDTA.
(A) Uv-vis spectra, (B-C) TEM micrographs with size distribution histogram (n = 500) of AgNPs synthesized in 0.6% (B) and 17% EDTA (C). Scale bars: (B-C) 20 nm, inset (B) 10 nm, and inset (C) 5 nm.
Fig 2.
Growth of (A) C. albicans and (B) S. aureus colonies treated with AgNPs in 0.6% and 17% EDTA for MFC/MBC determination after broth microdilution assay. C- = negative control.
Table 1.
MIC and MFC/MBC values for microbial planktonic cells treated with AgNPs (μg/ml) in 0.6% and 17% EDTA.
Fig 3.
Metabolic activity of (A-C) C. albicans and (D-F) S. aureus biofilm treated with AgNPs in 0.6% and 17% of EDTA at several concentrations (1–512 μg/ml) at 1 (A,D), 10 (B,E) and 30 (C,F) min. C = negative control, E = 17% EDTA.
Table 2.
MIC values of AgNPs (1–512 μg/ml) in 0.6% and 17% EDTA solutions against C. albicans biofilm.
Table 3.
MIC values of AgNPs (1–512 μg/ml) in 0.6% and 17% EDTA solutions against S. aureus biofilm.
Fig 4.
SEM micrographs (A) and diameter distribution histograms (B) of C. albicans and S. aureus cells in biofilms exposed to PBS 1x as control, 17% EDTA and AgNPs (16 μg/ml) in 17% EDTA during 10 min. Loss of cell volume and pits are pointed out (arrows, insets). Scale bars: (C. albicans) 10 μm and (S. aureus) 2.5 μm.
Fig 5.
SEM micrographs of C. albicans and S. aureus biofilm exposed to AgNPs (512 μg/ml) in 17% EDTA after 10 min.
(A) yeasts and hypha of C. albicans covered with silver agglomerates, inset showing the presence of small agglomerates in yeasts; (B) cells of S. aureus completely covered with AgNPs (enclosed area 1) and others with smaller agglomerations (enclosed area 2), inset showing cell deformation; (C) EDS analysis providing the chemical composition of enclosed area 1 (1 EDS) and enclosed area 2 (2 EDS) over the cell surface of S. aureus. Scale bars: A = 5 μm (inset = 1 μm); B = 2 μm (inset 0.5 μm).
Fig 6.
AFM analysis of dentin treated for smear layer removal.
(A-B) 2-D and 3-D AFM images, (C) surface roughness and mean depth values of the smear layer removal in treated dentin after 1 and 10 min of exposure time. Negative control (C-), 17% EDTA (E) and two concentrations of AgNPs (16 and 512 μg/ml) synthesized in 17% EDTA. (*) Kruskal Wallis Test with post hoc Dunn's test (P <0.05). Scale bars, 20 μm.
Fig 7.
SEM micrographs of dentin treated with 17% EDTA and 17% EDTA-AgNPs.
Low (A, C) and high (B, D) magnifications show dentin free of smear layer at all treatments tested at 1 and 10 min. Scale bars: (A, C) 100 μm; (B, D) 20 μm.
Fig 8.
SEM micrographs of dentin treated with 17% EDTA-AgNPs at 512 μg/ml of silver concentration.
(A) BSE provided the localization of non-uniform aggregates, (B) EDS spectrum showing the presence of silver in the aggregate shown in (A), (C) silver aggregates seen outside and (D) inside dentinal tubules, (E) higher magnification of aggregates, (F) some aggregates were observed probably covered by EDTA (arrow). Scale bars: (A) 5 μm, (C-D) 500 nm, (E-F) 200 nm.
Fig 9.
Stereoscopic images of dentin treated with 17% EDTA-AgNPs at two silver concentrations after 1 and 10 min.
Fig 10.
Demineralization values of dentin treated with 17% EDTA-AgNPs after 1 and 10 min.
Average and standard deviation of (A) amount of extracted calcium, (B) extracted magnesium, (C) MH values and (D) XRD patterns. Negative control (C-), 17% EDTA (E) and two concentrations of AgNPs (16 and 512 μg/ml) synthesized in 17% EDTA. (*) Mann-Whitney U test and Kruskal Wallis Test with post hoc Dunn's test (P < 0.05).
Fig 11.
Plausible role of EDTA in the synthesis of AgNPs.
Scale bar: 5 nm.