Evaluation of antiplasmodial activity and cytotoxicity assays of amino acids functionalized magnetite nanoparticles: Hyperthermia and flow cytometry applications.

We report the synthesis of magnetite nanoparticles (MNP) and their functionalization with glycine (MNPGly), ß-alanine (MNPAla), L-phenylalanine (MNPPhAla), D-(-)-α-phenylglycine (MNPPhGly) amino acids. The functionalized nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), electron paramagnetic resonance (EPR), vibrating sample magnetometry (VSM), Mössbauer spectroscopy (MS), magnetic hyperthermia (MH), dynamic light scattering and zeta potential. The functionalized nanoparticles had isoelectric points (IEP) at pH ≃ 4.4, 5.8, 5.9 and 6.8 for samples MNPGly, MNPAla, MNPPhGly and MNPPhAla, respectively, while pure magnetite had an IEP at pH 5.6. In the MH experiments, the samples showed specific absorption rate (SAR) of 64, 71, 74, 81 and 66 W/g for MNP, MNPGly, MNPAla, MNPPhGly, and MNPPhAla, respectively. We used a flow cytometric technique to determine the cellular magnetic nanoparticles plus amino acids content. Magnetic fractionation and characterization of Resovist® magnetic nanoparticles were performed for applications in magnetic particle imaging (MPI). We have also studied the antiproliferative and antiparasitic effects of functionalized MNPs. Overall, the data showed that the functionalized nanoparticles have great potential for using as environmental, antitumor, antiparasitic agents and clinical applications.

Copolymer-nanocapsules of zinc phenyl-thio-phthalocyanine and amphotericin-B in association with antimicrobial photodynamic therapy (A-PDT) applications against Candida albicans yeasts.

Antimicrobial Photodynamic Therapy (A-PDT) is a modern and non-invasive therapeutic modality. Nanostructures like the polymeric nanocapsules (NC) has proved to be a system that has enormous potential to improve current antimicrobial therapeutic practice. NC of Zinc phenyl-thio-phthalocyanine and Amphotericin B association (NC/ZnS4Pc + AMB) built with poly(lactide-co-glycolide) (PLGA) 50:50 using the preformed polymer interfacial deposition method were developed at a 0.05 mg mL- 1 theoretical concentration to improve antifungal activity with two actives association and assistance from PDTa. It showed an average particle diameter of 253.8 ±â€¯17.3, an average polydispersity index of 0.36 ±â€¯0.01, and a negative Zeta potential average of -31.03 ±â€¯5.54 for 158 days. UV-vis absorption and emission spectroscopy analyses did not show changes in photophysical properties in the steady-state of NC/ZnS4Pc + AMB counterparts free ZnS4Pc. The encapsulation percentage of actives was 89.24 % and 7.40 % for ZnS4Pc and AMB, respectively. Cell viability assay using NIH/3T3 ATCC® CRL-1658 ™ cells line showed no cytotoxicity for the concentrations tested. The photodynamic activity assay using NC/ZnS4Pc + AMB diluted showed fungal toxicity against Candida albicans yeast with energetic fluences of 12 J.cm-2 and 25 J.cm-2 by a decrease in cell viability. The MFC assay demonstrated a fungistatic activity for the conditions employed in the PDTa assay. The results show that NC/ZnS4Pc + AMB is a promising nanomaterial for antimicrobial inactivation using PDT.

In vivo biocompatibility of Resilon compared with gutta-percha in a pre-clinical model.

BACKGROUND: The aim of this study was to investigate in vivo biocompatibility of Resilon, compared with gutta-percha, at short and long-term following implantation in a rat subcutaneous implantation model. MATERIALS AND METHODS: Male Wistar rats were implanted subcutaneously with either Resilon or gutta-percha or were sham controls. Tissues were harvested at 8 days or 60 days after implantation and were evaluated histologically for inflammation and fibrous encapsulation. The severity of histologic injury, scored on a scale of 0-4 and quantitative analysis of the capsule wall thickness were determined for statistical analysis. Data were analyzed by Student t-test, one-way analysis of variance, Kruskal-Wallis or Mann-Whitney's tests as appropriate. A value of P ≤ 0.05 was considered statistically significant. RESULTS: No behavioral changes or visible signs of physical impairment were observed at 8 days or 60 days post-implantation. Histopathologic observation of the implanted sites at each time-point showed that both Resilon and gutta-percha implants induced foreign body reaction, showing minimal to mild inflammatory reactions in most cases, which diminished significantly with time. Compared with gutta-percha, the capsule wall was thinner (P < 0.05) after Resilon implantation at day 8 and significantly (P = 0.01) thicker at day 60. In addition, capsule wall thickness showed a trend to increase with time after implantation in the Resilon groups (P < 0.05), opposed to the significant decrease (P = 0.016) observed after implantation in the gutta-percha groups, suggesting lesser long-term biocompatibility of Resilon. CONCLUSION: Our findings validate Resilon as an in vivo biocompatible material. However, our data suggest that long-term biocompatibility of Resilon, despite validated, is inferior to that of gutta-percha control.

Contour integration in the primary visual cortex of the opossum.

To investigate whether contour integration is a generalized mammalian feature we studied single cells in V1 on the South-America opossum ( ), a plesiomorphic animal believed to retain basic characteristics of early mammals. We observed that when a cell's receptive field (RF) was masked (i.e. an artificial scotoma was produced), sweeping a long bar (several times the length of the RF) at the cell's preferred orientation elicited robust responses in many cells (28/103, or 27%). Therefore, some cells in the primary visual cortex of the opossum interpolate under conditions consistent with physical occlusion. The present results indicate that the property of contour integration appears to be a basic property of the mammalian visual system.