Synthesis and characterization of PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP (PVA/MFCP) nanostructures
Identification and characterization of PVA/MFCP (Fig. 1) were performed by using scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), N2 adsorption/desorption isotherms and thermal behaviour.
According to our previous reports, structure of Fe3O4@SiO2@CPS@SID@Ni was validated through spectral data (Fig. 2) such as SEM, FT-IR, XRD, EDX and VSM [14]. In this work, SEM, FT-IR, XRD and VSM spectral data of PVA/MFCP nanostructures was compared with our previous reports.
Previous reports in SEM image of Fe3O4@SiO2@CPS@SID@Ni (Fig. 3-I) suggest that its particle size is in the nanoscale range with uniform morphology [14], in the final structure (PVA/MFCP) the morphology was preserved (Fig. 3-II) which proves that the electrospinning procedure were optimal conditions and the PVA/MFCP nanostructures was in the nanoscale range.
All peaks of the proposed structure were observed in the FT-IR spectrum of PVA/MFCP nanostructures (Fig. 4-II). Comparison spectra of Fe3O4@SiO2@CPS@SID@Ni [14] and PVA/MFCP nanostructures showed that in addition to peaks Ni-N, Fe-O, Si-O, C = C, C = O, CN, C-H and N-H, there are peaks related to Ni-O and O-H in areas 700 cm − 1 and 3200 cm− 1, respectively, in spectrum of PVA/Fe3O4@SiO2@CPS@SID@Ni.
The XRD pattern of PVA/MFCP nanostructures was similar to the XRD pattern of Fe3O4@SiO2@CPS@SID@Ni and in positions of 2θ angles at 30.2, 35.69, 43.5, 53.75, 57.6 and 63.8 due to the standard XRD pattern of crystalline cubic spinel Fe3O4 nanoparticles were shown (Fig. 5) [3, 14].
According to our previous report, vibrating sample magnetometer related to structure Fe3O4@SiO2@CPS@SID@Ni, 23.8 emu g− 1 was observed [14], vibrating sample magnetometer related to PVA/ MFCP, 7.6 emu g− 1 was observed (Fig. 6), decreasing the amount of VSM proves the structure of the proposed product.
According to N2 adsorption/desorption isotherms of synthesized material under optimal conditions in Fig. 7, the adsorption/ desorption isotherms of both sample are similar to first type of classical isotherms which confirms microporous distribution of products [27, 28]. Based on data obtained from BET technique, PVA/MFCP nanostructures have more surface area than PVA/Fe3O4@SiO2 (1170 m2/g compared to 680 m2/g). It means that incorporation of the nanostructures in core-shell composite network could enhance the surface area of the final products.
Thermal behavior of Fe3O4@SiO2 and PVA/MFCP nanostructures synthesized under optimal conditions are showed in Fig. 8. According to this Fig, the samples have thermal behavior including evaporation the solvent (near 100 °C), destruction trapping solvent (around 140°C) and disintegrate the main structure. The data obtained from this curve showed that PVA/MFCP nanostructures have higher thermal stability (235 °C than 187 °C). As an important result, synthesis of nanostructures with desirable components could enhance the thermal stability of compound with high degree. This product can be used in different area such as novel catalyst with high thermal stability [29, 30].
Anticancer properties
Anticancer activity of PVA/MFCP nanostructures on MCF-7 breast cancer cells in 24 and 48 hours at a concentration of 200 µg/mL showed the maximum effect and were about 40% and 32% than control, respectively (Fig. 9).
IC50 values of PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures at 24h and 48h were calculated as 152 µg/mL and 119 µg/mL, respectively.
From the results of anticancer activity, it can be concluded that the effectiveness of PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures depends on time and concentration.
Antimicrobial properties
According to our previous report, the antimicrobial properties of magnetic nanoparticles were investigated on Fusarium oxysporum (PTCC 5115) as fungi and Gram-positive pathogenic strains including Staphylococcus aureus (PTCC 1189) and Rhodococcus equi (PTCC 1633), Gram-negative pathogenic strains including Proteus mirabilis (PTCC 1776), Escherichia coli (PTCC 1399) and Salmonella enterica subsp. enterica (PTCC 1709) that were prepared from the Persian Type Culture Collection (PTCC), Tehran, Iran. In this study, the antimicrobial properties of PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures on the mentioned strains were evaluated and the results were presented in Table 1.
Table 1
Antimicrobal activities of PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP
Product / Antibiotics
|
Fungi
|
gram- positive
|
gram- negative
|
5115
|
1189
|
1633
|
1776
|
1399
|
1709
|
MIC
|
MFC
|
MIC
|
MBC
|
MIC
|
MBC
|
MIC
|
MBC
|
MIC
|
MBC
|
MIC
|
MBC
|
P/MFCP
|
256
|
256
|
128
|
256
|
8
|
32
|
16
|
32
|
8
|
16
|
32
|
128
|
SID MNPs[14]
|
128
|
256
|
256
|
512
|
16
|
32
|
16
|
32
|
8
|
16
|
64
|
128
|
Drug a [14]
|
-
|
-
|
0.5
|
1
|
1
|
4
|
0.5
|
2
|
4
|
8
|
4
|
8
|
Drug b [14]
|
32
|
64
|
8
|
16
|
8
|
16
|
16
|
16
|
-
|
-
|
8
|
16
|
P/MFCP: PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures as novel magnetic fibrous composite polymer
SID MNPs: Fe3O4@SiO2@CPS@SID@Ni
MIC, MBC and MFC Values reported as µg/mL
For fungi; Drug a: Tolnaftate, Drug b: Terbinafine; For bactria; Drug a: Gentamicin, Drug b: Penicillin
|
As shown in the Table 1, antimicrobial activity of PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures and Fe3O4@SiO2@CPS@SID@Ni based on minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were evaluated and have been compared with Tolnaftate, Terbinafine as commercial antifungal drugs and Gentamicin, Penicillin, as commercial antibacterial drugs.
Based on MBC and MFC Values, the results of antimicrobial activity from PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures was very similar to Fe3O4@SiO2@CPS@SID@Ni.
The results showed that Tolnaftate as commercial antifungal drug did not effect on Fusarium oxysporum, but PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures and Fe3O4@SiO2@CPS@SID@Ni showed MFC 256 µg/mL in addition, Penicillin's commercial drug did not effect on Escherichia coli, but PVA/Fe3O4@SiO2@CPS@SID@Ni MFCP nanostructures and Fe3O4@SiO2@CPS@SID@Ni with MBC 16 µg/mL showed acceptable effects.