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1.  Synthesis, characterization and in vitro biocompatibility study of Au/TMC/Fe3O4 nanocomposites as a promising, nontoxic system for biomedical applications 
The unique properties and applications of iron oxide and Au nanoparticles have motivated researchers to synthesize and optimize a combined nanocomposite containing both. By using various polymers such as chitosan, some of the problems of classic core–shell structures (such as reduced saturation magnetization and thick coating) have been overcome. In the present study, chitosan and one of its well-known derivatives, N-trimethylchitosan (TMC), were applied to construct three-layer nanocomposites in an Au/polymer/Fe3O4 system. It was demonstrated that replacement of chitosan with TMC reasonably improved the properties of the final nanocomposites including their size, magnetic behavior and thermal stability. Moreover, the results of the MTT assay showed no significant cytotoxicity effect when the Au/TMC/Fe3O4 nanocomposites were applied in vitro. These TMC-containing magnetic nanoparticles are well-coated by Au nanoparticles and have good biocompatibility and can thus play the role of a platform or a label in various fields of application, especially the biomedical sciences and biosensors.
PMCID: PMC4578445  PMID: 26425418
Au/polymer/Fe3O4 nanocomposites; Au nanoparticles; cell viability; magnetic nanoparticles; N-trimethyl chitosan
2.  DNA Interaction and DNA Cleavage Studies of a New Platinum(II) Complex Containing Aliphatic and Aromatic Dinitrogen Ligands 
A new Pt(II) complex, [Pt(DIP)(LL)](NO3)2 (in which DIP is 4,7-diphenyl-1,10-phenanthroline and LL is the aliphatic dinitrogen ligand, N,N-dimethyl-trimethylenediamine), was synthesized and characterized using different physico-chemical methods. The interaction of this complex with calf thymus DNA (CT-DNA) was investigated by absorption, emission, circular dichroism (CD), and viscosity measurements. The complex binds to CT-DNA in an intercalative mode. The calculated binding constant, Kb, was 6.6 × 104 M−1. The enthalpy and entropy changes of the reaction between the complex and CT-DNA showed that the van der Waals interactions and hydrogen bonds are the main forces in the interaction with CT-DNA. In addition, CD study showed that phenanthroline ligand insert between the base pair stack of double helical structure of DNA. It is remarkable that this complex has the ability to cleave the supercoiled plasmid.
PMCID: PMC3253441  PMID: 22235195
3.  New surface-modified solid lipid nanoparticles using N-glutaryl phosphatidylethanolamine as the outer shell 
Solid lipid nanoparticles (SLNs) are colloidal carrier systems which provide controlled-release profiles for many substances. In this study, we prepared aqueous dispersions of lipid nanoparticles using a modified, pH-sensitive derivative of phosphatidylethanolamine.
SLNs were prepared using polysorbate 80 as the surfactant and tripalmitin glyceride and N-glutaryl phosphatidylethanolamine as the lipid components. Particle size, polydispersity index, and zeta potential were examined by photon correlation spectroscopy. Morphological evaluation was performed using scanning electron microscopy, atomic force microscopy, and differential scanning calorimetry.
Photon correlation spectroscopy revealed a particle hydrodynamic diameter of 165.8 nm and zeta potential of −41.6.0 mV for the drug-loaded nanoparticles. Atomic force microscopy investigation showed the nanoparticles to be 50–600 nm in length and 66.5 nm in height. Differential scanning calorimetry indicated that the majority of SLNs possessed less ordered arrangements of crystals compared with corresponding bulk lipids, which is favorable for improving drug-loading capacity. Drug-loading capacity and drug entrapment efficiency values for the SLNs were 25.32% and 94.32%, respectively.
The SLNs prepared in this study were able to control the release of triamcinolone acetonide under acidic conditions.
PMCID: PMC3218572  PMID: 22114489
solid lipid nanoparticles; high-shear homogenization; triamcinolone acetonide; tripalmitin; phosphatidylethanolamine
4.  Identification of Binding Mode of a Platinum (II) Complex, PtCl2(DIP), and Calf Thymus DNA 
The Pt(II) complex, PtCl2(DIP) (DIP = chelating dinitrogen ligand: 4,7-diphenyl-1,10-phenanthroline), was synthesized and characterized by elemental analysis (CHN) and 1H NMR and UV-vis techniques. The binding of this complex to calf thymus DNA was investigated using various physicochemical methods such as spectrophotometric, circular dichroism, spectrofluorometric, melting temperature, and viscosimetric techniques. Upon addition of the complex, important changes were observed in the characteristic UV-Vis bands (hyperchromism) of calf thymus DNA (CT-DNA): increase in melting temperature, sharp increase in specific viscosity of DNA, and induced CD spectral changes. Also the fluorescence spectral characteristics and interaction of Pt complex with DNA have been studied. Pt bound to DNA showed a marked decrease in the fluorescence intensity. The results show that both the complex and the NR molecules can intercalate competitively into the DNA double-helix structure. The experimental results show that the mode of binding of the this complex to DNA is classical intercalation.
PMCID: PMC3202101  PMID: 22110411

Results 1-4 (4)