New water-soluble Fe3O4@SiO2 magnetic nanoparticles functionalized with levetiracetam drug for adsorption of essential biomolecules by case studies of DNA and HSA

Sol-Gel Synthesis of Dy-Substituted Ni0.4Cu0.2Zn0.4(Fe2-xDyx)O4 Nano Spinel Ferrites and Evaluation of Their Antibacterial, Antifungal, Antibiofilm and Anticancer Potentialities for Biomedical Application

Background

The constant rise of microbial biofilm formation and drug resistance to existing antimicrobial drugs poses a significant threat to community health around the world because it reduces the efficacy and efficiency of treatments, increasing morbidity, mortality, and health-care expenditures. As a result, there is an urgent need to develop novel antimicrobial agents that inhibit microbial biofilm formation.

Methods

The [Ni_0.4Cu_0.2Zn_0.4](Fe_2-xDy_x)O₄(x≤0.04) (Ni-Cu-Zn) nano spinel ferrites (NSFs) have been synthesized by the sol–gel auto-combustion process and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and transmission electron microscopy (TEM). The antimicrobial, antibiofilm and antiproliferative activities of Ni-Cu-Zn NSFs were also examined.

Results

The XRD pattern confirms the secondary phase DyFeO₃ and Fe₂O₃ for substituted Dy³⁺ samples, and the crystallite size ranged from 10 to 19 nm. TEM analysis of NSFs revealed that the particles were cube-shaped and 15nm in size. NSFs exhibited significant antimicrobial, antibiofilm and antiproliferative activity. At concentration of 1 mg/mL, it was found that the NSFs (ie, x=0.0, x=0.01, x=0.02, x=0.03 and x=0.04) inhibit biofilm formation by 27.6, 26.2, 58.5, 33.3 and 25% for methicillin-resistant Staphylococcus aureus (MRSA) and 47.5, 43.5, 48.6, 58.3 and 26.6% for Candida albicans, respectively. SEM images demonstrate that treating MRSA and C. albicans biofilms with NSFs significantly reduces cell adhesion, colonization and destruction of biofilm architecture and extracellular polymeric substances matrices. Additionally, SEM and TEM examination revealed that NSFs extensively damaged the cell walls and membranes of MRSA and C. albicans. Huge ultrastructural alteration such as deformation, disintegration and separation of cell wall and membrane from the cells was observed, indicating significant loss of membrane integrity, which eventually led to cell death. Furthermore, it was observed that NSF inhibited the cancer cell growth and proliferation of HCT-116 in a dose-dependent manner.

Conclusion

The current study demonstrated that the synthesized Ni-Cu-Zn NSFs could be used to develop potential antimicrobial surface coatings agents for a varieties of biomedical-related materials and devices in order to prevent the biofilms formation and their colonization. Furthermore, the enhanced antiproliferative properties of manufactured SNFs suggest a wide range of biomedical applications.

Interaction of human hemoglobin (HHb) and cytochrome c (Cyt c) with biogenic chloroxine-conjugated silver nanoflowers: spectroscopic and molecular docking approaches

In this research, the biological activity of the antibacterial drug Chloroxine-conjugated biogenic AgNPs (COX-AgNPs) was investigated in simulated physiological conditions (pH = 7.40). Different spectroscopic methods such as UV-visible, fluorescence, and circular dichroism spectroscopic and docking simulation were employed to evaluate the structural changes in the most important blood proteins (human hemoglobin (HHb) and Cytochrome c (Cyt c)) in the presence of COX-AgNPs. The results showed that the COX-AgNPs can bind to HHb and Cyt c and the secondary structure of these proteins remains unchanged, which is crucial in providing insights into the side effects of newly synthesized drugs on their carriers.Communicated by Ramaswamy H. Sarma.

Multispectroscopic and molecular docking studies on DNA binding of guaifenesin drug

The interaction mechanism of guaifenesin drug; (RS)-3-(2-methoxyphenoxy)propane-1,2-diol; and calf thymus DNA was characterized by multiple spectroscopic and molecular docking approaches. The changes in drug electronic absorption with increasing DNA concentration and also the observed significant quenching of guaifenesin emission in the presence of DNA proved the complex formation between guaifenesin and DNA during the interactions. Both the binding constant and thermodynamic parameters for the interaction have been calculated in 283, 298, and 310 K at pH 7.4. The results Δ H 0  = 17.87 kJ/mol and Δ S 0  = 143.31 J/mol.K confirmed the role of hydrophobic force in the guaifenesin-DNA interaction. Circular dichroism study showed that guaifenesin causes decrease in the negative band of CT-DNA and at the same time the positive band increases which indicated the transition of DNA conformation from B to A. KI quenching experiment specifies that guaifenesin binds to DNA via nonintercalative mode. The competitive studies based on known Hoechst 33258 and methylene blue probes proved the groove binding mode in guaifenesin-DNA adduct. Further, full agreement of molecular docking simulation with the experimental results of binding constant and interaction mode, support high accuracy of the results.

Exploring the binding mechanisms of inorganic magnetic nanocarrier containing L-Dopa with HSA protein utilizing multi spectroscopic techniques

In this study, the interaction of Fe₃O₄@CaAl-LDH@L-Dopa nanoparticles (NPs) with human serum albumin (HSA) was investigated in simulated physiological conditions applying UV-visible, fluorescence, and circular dichroism (CD) spectroscopic techniques. The consequences of UV-vis and CD spectroscopy demonstrated that the interaction of HSA to Fe₃O₄@CaAl-LDH@L-Dopa NPs enforced some conformational alterations within HSA. The fluorescence spectroscopy analysis indicated that by enhancing temperature, the Stern-Volmer quenching constant (K_sv) was decreased, which is relevant to a static quenching mechanism. The binding constant (K_b) was 7.07 × 10⁴ M^-1 while the number of the binding site (n) was 0.94 which is in compromise with its binding constant. Also, thermodynamic parameters (ΔH° > 0, ΔG° < 0, and ΔS° > 0) have suggested that hydrophobic forces perform a key role in the interaction of HSA with Fe₃O₄@CaAl-LDH@L-Dopa NPs. Displacement studies successfully carried out using the Warfarin and Ibuprofen have predicted that the binding of Fe₃O₄@CaAl-LDH@L-Dopa NPs to HSA is situated at site II (subdomain IIIA).Communicated by Ramaswamy H. Sarma.

Multispectroscopic analysis, atomic force microscopy, molecular docking and molecular dynamic simulation studies of the interaction between [SnMe2Cl2(Me2phen)] complex and ct-DNA in the presence of glucose

In this study, the spectroscopic methods (UV-vis, fluorimetric), Atomic force microscopy, and computational studies (molecular docking and molecular dynamic simulation) were used to investigate the interaction of [SnMe₂Cl₂(Me₂phen)] complex with CT-DNA in the presence of glucose. The results showed the complex in the medium containing glucose has less effect on calf thymus DNA (ct-DNA) than the medium without glucose. Cytotoxicity of [SnMe₂Cl₂(Me₂phen)] complex on MCF-7 cells was examined and showed Sn(IV) complex possesses potential cytotoxicity against this cell line. Molecular docking study showed that Sn(IV) complex interacts with DNA by groove binding mode. Radius of gyration (Rg) was smaller upon binding of the Sn(IV) complex suggesting a more compact structure of DNA in the presence of Sn(IV) complex.Communicated by Ramaswamy H. Sarma.

Synthesis of Ni0.5Co0.5-xCdxFe1.78Nd0.02O4 (x ≤ 0.25) nanofibers by using electrospinning technique induce anti-cancer and anti-bacterial activities

Here we report the electrospinning synthesis of Cd-substituted Ni-Co ferrite Ni_0.5Co_0.5-xCd_xFe_1.78Nd_0.02O₄ (x ≤ 0.25) nanofiber (NFs) with a very low concentration of Nd as a dopant. The structure and surface morphology of the Ni_0.5Co_0.5-xCd_xFe_1.78Nd_0.02O₄ (x ≤ 0.25) NFs were analyzed by X-ray powder pattern (XRD), transmission and scanning electron microscopes (TEM) along with Energy-dispersive X-ray (EDX). We have examined the biological applications of the Ni_0.5Co_0.5-xCd_xFe_1.78Nd_0.02O₄ (x ≤ 0.25) NFs on both cancerous cells and bacterial cells. We have found that Ni_0.5Co_0.5-xCd_xFe_1.78Nd_0.02O₄ (x ≤ 0.25) NFs produced inhibitory action on the human colorectal carcinoma cells (HEK-293) and also showed inhibitory action on the bacterial strains (S. aureus and E. coli) respectively. Finally, this is the first report on the synthesis of Cd- substituted Co-Ni ferrite nanofibers using electrospinning technique exhibiting anti-cancer and anti-bacterial activities.Communicated by Ramaswamy H. Sarma.

Synthesis of niobium substituted cobalt-nickel nano-ferrite (Co0.5Ni0.5NbxFe2-xO4 (x ≤ 0.1) by hydrothermal approach show strong anti-colon cancer activities

The combination of two or more nanoparticles found to be effective strategy to synthesize nanocomposites for better drug delivery and treatment. In the present study, we have combined cobalt (Co), nickel (Ni), niobium (Nb), and iron oxide (Fe₂O₄) and prepared niobium substituted cobalt-nickel nano-ferrite nanocomposites (Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) by using hydrothermal approach. We have characterized the structure and morphology of nanocomposites by using XRD, EDX, TEM and SEM methodologies. We have examined the impact of nanocomposites (Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) on cancerous cells (human colorectal carcinoma cells, HCT-116) by using MTT assay. We have also checked the impact of nanocomposites on normal and non-cancerous cells (human embryonic kidney cells, HEK-293) to confirm the specificity of their actions. Post- 48 h treatment of Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) led to dose-dependent inhibition of cancer cells growth and proliferation. However, no cytotoxic effect was observed on the normal cells (HEK-293). In addition, DAPI stained nuclear DNA staining analysis demonstrates that the Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) treatment also caused nuclear DNA disintegration which is the marker for programmed cell death. These results demonstrate that synthesized nanocomposites Co_0.5Ni_0.5Nb_xFe_2-xO₄ (x ≤ 0.1) selectively target the colon cancer cells and induce cancer cell death.Communicated by Ramaswamy H. Sarma.

Studies on the interaction of antibiotic drug rifampin with DNA and influence of bivalent metal ions on binding affinity

In this paper, the interaction between rifampin, a known antibiotic used against tuberculosis, and DNA helix is investigated by applying multiple biophysical and molecular modelling approaches in an aqueous solution at pH 7.4 and 5. It was proved that the fluorescence quenching of labeled probe DNA by rifampin is a result of the complex formation of rifampin in groove of DNA. Binding parameters were calculated using the logarithmic Hill equation to provide a quantitative term of the binding affinity between rifampin and DNA sites. The resulting ΔH⁰ = -122.76 ± 0.07 kJ/mol and ΔS⁰ = -308.19 ± 238.78 J/mol K confirms the role of the Van der Waals' forces and hydrogen bonding in the rifampin-DNA complexation. Furthermore, the influence of bivalent metal ions on the binding affinity was resulted in order of Cu(II) > Ca(II) > Co(II) > Zn(II).

Intercalation of manganese-mefenamic acid complex into double stranded of calf thymus DNA

The interaction of the [Mn(mef)₂(phen)H₂O] complex in which mef is mefenamic acid drug and phen is 1,10 phenanthrolin ligand with calf thymus DNA (ct-DNA) was studied by using different spectroscopic methods, molecular docking and viscometery. The competitive fluorescence and UV-Vis absorption spectroscopy indicated that the complex interacted with ctDNA via intercalating binding mode with the binding constant of 1.16 × 10⁴ Lmol^-1. The thermodynamic studies showed that the reaction between the complex and ctDNA is exothermic. Furthermore, the complex induced changes in DNA viscosity. Circular dichroism spectroscopy (CD) was employed to measure the conformational changes of ctDNA in the presence of the complex and verified intercalation binding mode. The molecular modeling results illustrated that the complex interacted via intercalation by relative binding energy of -28.45 kJ mol^-1.