According Table 1 S. aureus showed higher sensitivity to both nanoparticles than other strains. As well as, a moderate sensitivity was also observed for the strains P. aeruginosa and E. coli. The MIC and MBC endpoints for strains aeruginosa. aureus and E. coli were observed to be the same and 0.24 and 0.48 mg/ml respectively (Table 2). The BiOI and CFO/BiOI can have inhibitory and lethal effects on B. cereus in lower amounts. In general, BiOI alone and in combination with CFO (CFO/BiOI) show the same antimicrobial effect.
6.1 Analysis of XRD
Using X'Pert Pro system from the Panalytical company, X-ray diffraction patterns of CoFe2O4 BIOI and CFO/BiOI nanofiber were reported under the following conditions: 40 mA, 40 kV, step size: 0.02, and timer per step 1 s/step. The XRD analysis of CoFe2O4 NPs is displayed in Figure 1. As seen in Figure 1a, the peaks at 2θ values of 30.19◦, 35.53◦, 43.17◦, 53.54◦, 57.087◦, 62.68◦ and 74.20◦ were respectively correspond to the (220), (311), (222), (400), (422), (511) and (440) planes with a cubic spinel structure (EX PAPER). In Figure 1b, the peaks observed of BiOI in the 2θ angles of 29.71◦, 31.75 ◦, 37.26◦, 39.30◦, 45.51◦, 46.62◦ and 51.51◦ related to (312), (004), (204), (020), (604), (316) and (912) reflections plane.
6.2 Analysis of FE-SEM
The Field Emission Scanning Electron Microscope (FE-SEM) is similar to the SEM microscope and generally retains the basic characteristics of SEM such as resolution, depth of field, signal diversity, and processing, as well, there is no need to conduct the sample in FE-SEM and it is possible to create a liquid injection system and it is also possible to observe the dynamics of the gas-liquid-solid system.
FE-SEM tests of sample BiOI and CFO/BiOI were performed using the device according SIGMA VP model system from ZEISS Company and one of the important results obtained from FE-SEM test was the uniform distribution of spherical nanoparticles. Figure2 displays the morphology of FE-SEM and also showed that the particle size is in nanometers.
The results of SEM test showed that particle BiOI had a size of 76-34 and particle CFO/BiOI had a particle size of 51-51 nm, which corresponds to the size given in the XRD test. The result of SEM test showed non-uniform accumulation due to magnetic force in the morphology of CFO / BiOI particles.
EDAX test was utilized to determine the elements present on the surface of CFO/BiOI nanocomposite. EDX analysis indicated pure CoFe2O4/BiOI nanoparticles formation; Figure 3a depicts the three elements that make up synthesized BiOI, whereas Figure 3b depicts the purity of CoFe2O4/BiOI nanoparticles, as well as their constituents. Figure 4 demonstrates the existence of additional elements O, Fe, Co, Bi, and I in the nanocomposite surface, which are precisely the same elements found in the EDAX test, and no peak was seen for another element, according to the corresponding elemental mappings results.
6.3 Cytotoxicity of CFO/BiOI nanocomposites
The cell survival MTT assay utilizing ELISA READER method was used to evaluate the cytotoxicity of the synthesized nanocomposite and in order to do this, they incubated 0.06 mg / ml and 0.48 mg / ml for 24 hours. As mentioned in the previous article, the same goes for this synthesis, the analysis indicated a survival rate of more than 50% for the maximum concentration of 0.06 mg/ml and the obtained data show that the nanocomposite synthesized by solvothermal method has the ability to kill bacteria and of course, this means that the ability is concentration dependent and we see more cell death with increasing concentration. In addition, based on the results, the IC50 value was determined to be 0.06 mg / ml. Energy Dispersive X-ray (EDAX) and corresponding elemental mappings test results were exactly equal and showed that the surface elements present on the surface of CFO/BiOI nanocomposite include O, Fe, Co, Bi, I.
Table 1. Bacterial growth inhibition zone (mm) based on the nanoparticle concentration
Bacteria
|
Inhibition Zone (mm)
|
BiOI (0.48 mg)
|
CFO/BiOI (0.48)
|
SXT
|
GM
|
AMX
|
CRO
|
CF
|
Bacillus cereus
|
18
|
18
|
25
|
25
|
R
|
22
|
R
|
Pseudomonas aeruginosa
|
15
|
15
|
R
|
R
|
R
|
16
|
R
|
Escherichia coli
|
17
|
17
|
32
|
R
|
R
|
32
|
R
|
Staphylococcus aureus
|
27
|
27
|
37
|
37
|
R
|
R
|
R
|
Abbreviations: R, resistant
Table 2. MIC and MBC CFO/BiOI, BiOI nanoparticles
MIC(mg/ml)
|
MBC(mg/ml)
|
Bacteria
|
0.24
|
0. 48
|
Escherichia coli
|
0.24
|
0.48
|
Staphylococcus aureus
|
0.24
|
0.48
|
Pseudomonas aeruginosa
|
0.06
|
0.12
|
Bacillus cereus
|