Electrochemical determination of purine and pyrimidine bases using a 1,10-phenanthroline-Fe3O4 nanoparticles-graphene oxide-chitosan nanocomposite.

A 1,10-phenanthroline-Fe3O4 nanoparticles-graphene oxide-chitosan nanocomposite (Phen-Fe3O4 NPs-GO-Chi) was fabricated and used to modify a glassy carbon (GC) electrode. The modified surface of the electrode was characterized by field emission-scanning electrochemical microscopy. Then, the prepared electrode was used as a sensor for simultaneous determination of purine and pyrimidine bases in DNA. The Phen-Fe3O4 NPs-GO-Chi composite modified electrode showed excellent response toward guanine (G), adenine (A), thymine (T) and cytosine (C). The sensor displayed higher effective surface, an appropriate peak-to-peak separation, and a larger peak current compared to the bare electrode. The evaluated detection limits of G, A, T, and C concentrations are 12, 4, 22, and 9 µM over the concentration range of 15-500, 15-400, 40-1000 and 40-1400 µM, respectively. In addition, the results show that the modified electrode is stable for 7 days and has good repeatability and interfering molecules and ions have no significant effect on peak current. The proposed method was successfully applied for the determination of purine and pyrimidine bases in a fish DNA sperm sample as a real sample.

Poly (ε-Caprolactone)/Cellulose Nanofiber Blend Nanocomposites Containing ZrO2 Nanoparticles: A New Biocompatible Wound Dressing Bandage with Antimicrobial Activity.

Purpose: In the present study, the poly (ε-caprolactone)/cellulose nanofiber containing ZrO2 nanoparticles (PCL/CNF/ZrO2 ) nanocomposite was synthesized for wound dressing bandage with antimicrobial activity. Methods: PCL/CNF/ZrO2 nanocomposite was synthesized in three different zirconium dioxide amount (0.5, 1, 2%). Also the prepared nanocomposites were characterized by Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). In addition, the morphology of the samples was observed by scanning electron microscopy (SEM). Results: Analysis of the XRD spectra showed a preserved structure for PCL semi-crystalline in nanocomposites and an increase in the concentrations of ZrO2 nanoparticles, the structure of nanocomposite was amorphous as well. The results of TGA, DTA, DSC showed thermal stability and strength properties for the nanocomposites which were more thermal stable and thermal integrate compared to PCL. The contact angles of the nanocomposites narrowed as the amount of ZrO2 in the structure increased. The evaluation of biological activities showed that the PCL/CNF/ZrO2 nanocomposite with various concentrations of ZrO2 nanoparticles exhibited moderate to good antimicrobial activity against all tested bacterial and fungal strains. Furthermore, cytocompatibility of the scaffolds was assessed by MTT assay and cell viability studies proved the non-toxic nature of the nanocomposites. Conclusion: The results show that the biodegradability of nanocomposite has advantages that can be used as wound dressing.

Needle-shaped amphoteric calix[4]arene as a magnetic nanocarrier for simultaneous delivery of anticancer drugs to the breast cancer cells.

BACKGROUND: Chemotherapy as an important tool for cancer treatment faces many obstacles such as multidrug resistance and adverse toxic effects on healthy tissues. Drug delivery systems has opened a new window to overcome these problems. There has been a strong interest development of new platform and system for delivof chemotherapeutic agents. PURPOSE: In the present study, a green synthesis method was chosen and performed for preparation of a novel amphoteric calix[4]arene (Calix) macrocycle with low toxicity to the human body. MATERIALS AND METHODS: The amphoteric Calix was coated on the surface of Fe3O4 magnetic nanoparticles and used as a magnetic nanocarrier for simultaneous delivery of two anticancer agents, doxorubicin and methotrexate, against MCF7 cancer cells. Several chemical characterizations were done for validation of prepared nanocarrier, and in vitro loading and release studies of drugs were performed with good encapsulation efficiency. RESULTS: In vitro biological studies including hemolysis assay, erythrocytes sedimentation rate, red blood cells aggregation, cyto cellular internalization, and apoptosis evaluations were performed. Based on results, the developed nanocarrier has many advantages and capability for an efficient codelivery of DOX and MTX, which has a highly potent ability to kill cancer cells. CONCLUSION: All these results persuade us, this nanocarrier could be effectively used for cancer therapy of MCF7 breast cancer cells and is suitable for use in further animal studies in future investigations.

Effects of statins on the chemoresistance-The antagonistic drug-drug interactions versus the anti-cancer effects.

There has been growing interest in the potential anti-cancer activity of statins based on evidence of their anti-proliferative, pro-apoptotic, and radiosensitizing properties, but no studies have focused on the effects of statins on the chemoresistance. In spite of their direct cytostatic/cytotoxic effects on the cancer cells, statins via drug interactions may affect therapeutic effects of the chemotherapy agents and so cause chemoresistance in cancer cells. Here, we aim to present the molecular mechanisms underlying cytotoxic effects of statins on the cancer cells against those mechanisms by which statins may lead to chemoresistance, in order to clarify whether the positive effects of the co-treatment of statins on the efficiency of chemotherapeutic agents is due to the natural anti-cancer effects of statins or it is due to increasing the cellular concentrations of chemotherapy drugs in cancer cells.

Chitin/silk fibroin/TiO2 bio-nanocomposite as a biocompatible wound dressing bandage with strong antimicrobial activity.

Interconnected microporous biodegradable and biocompatible chitin/silk fibroin/TiO2 nanocomposite wound dressing with high antibacterial, blood clotting and mechanical strength properties were synthesized using freeze-drying method. The prepared nanocomposite dressings were characterized using SEM, FTIR, and XRD analysis. The prepared nanocomposite dressings showed high porosity above 90% with well-defined interconnected porous construction. Swelling and water uptake of the dressing were 93%, which is great for wound dressing applications. Haemostatic potential of the prepared dressings was studied and the results proved the higher blood clotting ability of the nanocomposites compared to pure components and commercially available products. Besides, cell viability, attachment and proliferation by MTT assay and DAPI staining on HFFF2 cell as a Human Caucasian Foetal Foreskin Fibroblast proved the cytocompatibility nature of the nanocomposite scaffolds with well improved proliferation and cell attachment. To determine the antimicrobial efficiencies, both disc diffusion method and colony counts were performed and results imply that nanocomposite scaffolds have high antimicrobial activity and could successfully inhibit the growth of E. coli, S. aureus, and C. albicans. Moreover, based on these results, the prepared chitin/silk fibroin/TiO2 nanocomposite dressing could serve as a kind of promising wound dressing with great antibacterial and antifungal properties.

Preparation of biocompatible and biodegradable silk fibroin/chitin/silver nanoparticles 3D scaffolds as a bandage for antimicrobial wound dressing.

One of the most serious challenge in wound care is difficulty of the infection control in wound healing process. Wound dressings with antimicrobial effects are useful to minimize the bacterial infections of wounds. In this study a biocompatible and biodegradable silk fibroin/chitin nanocomposite scaffolds with various content of silver nanoparticles (0.001, 0.01, and 0.1%) were fabricated via freeze-drying method for successful wound dressing application. The nanocomposite scaffolds have biocompatibility with high antimicrobial effects, good mechanical properties, and high porosity. Furthermore, swelling and water uptake, blood clotting, and biodegradability were also investigated. The antimicrobial evaluation with both disc diffusion method and colony counts imply that nanocomposite scaffolds have high antimicrobial activity and could successfully inhibit the growth of E. coli, S. aureus, and C. albicans. Also proliferation, cell viability, and cell attachment with MTT assay and DAPI staining on nHFFF2 cell, have proved the cytocompatibility nature of the nanocomposite scaffolds. All results revealed that prepared nanocomposite scaffolds are good candidate for wound dressing and could be use in further in-vivo uses.

(E,E)-N'-{4-[(2-Benzoyl-hydrazin-1-yl-idene)meth-yl]benzyl-idene}benzo-hydrazide.

In the title compound, C(22)H(18)N(4)O(2), the mol-ecules lie across an inversion centre. The dihedral angle between the mean planes of the central and terminal benzene rings is 66.03 (2)°. The mol-ecule displays trans and anti conformations about the C=N and N-N bonds, respectively. In the crystal, N-H⋯O hydrogen bonds, with the O atoms of C=O groups acting as acceptors, link the mol-ecules into a chain along [101].