Hypericin-loaded oil-in-water nanoemulsion synthesized by ultrasonication process enhances photodynamic therapy efficiency.

Hypericin (Hy) is a hydrophobic photosensitizer used in photodynamic therapy for cancer therapeutic. In this study, Hy-loaded oil-in-water (O/W) nanoemulsions (NEs) were produced by the ultrasonication method combing different biocompatible oils and surfactants to enhance Hy aqueous solubility and bioavailability. Experimental parameters were optimized by the characterization of droplet size, zeta potential, and physicochemical properties. In vitro studies based on the release profile, cytotoxicity, cell morphology, and Hy intracellular accumulation were assayed. Hy at 100 mg L-1 was incorporated into the low viscosity (~0.005 Pa s) NEs with spherical droplets averaging 20-40 nm in size and polydispersity index <0.02. Hy release from the NE was significantly higher (4-fold) than its suspension (p < 0.001). The NEs demonstrated good physical stability during storage at 5 °C for at least six months. The Hy-loaded NEs exhibited an IC50 value 6-fold lower than Hy suspension during PDT against breast cancer cell lines (MCF-7). Cell microscopy imaging confirmed the increased cytotoxic effects of Hy-loaded NEs, showing damaged and apoptotic cells. Confocal laser scanning microscopy evidenced greater Hy delivery through NE into MCF-7 cells followed by improved intracellular ROS generation. Our results suggest that the Hy-loaded NEs can improve hypericin efficacy and assist Hy-PDT's preclinical development as a cancer treatment.

Paper-Based Microfluidics Immunoassay for Detection of Canine Distemper Virus

ABSTRACT Paper-based devices present low-cost and are versatile, making them very attractive for clinical analysis. To manufacture those devices wax patterns are printed on paper surface and upon heating the wax permeates through the entire thickness of the paper, creating hydrophobic barriers that delimit test areas. Antibodies produced in rabbits against canine distemper virus (CDV) were physically adsorbed on the surface of gold nanoparticles (AuNPs) and incubated with CDV viral antigens, forming the immunocomplex. Anti-CDV antibodies were immobilized into the microchannels by physical adsorption, forming the test region. The test solution containing conjugated AuNPs was applied at the bottom of the microchannel and it was eluted with a phosphate buffer solution 0.01 M pH 7.4. When the solution containing the AuNPs reached the test zone the recognition of antigens contained on the immunocomplex occurred with the consequent development of a red line, which represents a positive outcome for the test. This method demonstrated the success of physical immobilization of antibodies on AuNPs and the physical immobilization of antibodies on cellulose's surface. This colorimetric assay brings simplicity and versatility to clinical analyses, presenting potential for CDV diagnosis.

Self-assembled FePt nanocrystals with large coercivity: reduction of the fcc-to-L1(0) ordering temperature.

Herein we report the synthesis and properties of Fe(55)Pt(45) nanoparticles, both monodisperse and self-assembled into hexagonal close-packed and cubic arrays of 4.0 +/- 0.2 nm size in an L1(0) structure, obtained by a modified polyol process. The new synthetic route improved the control over the particle composition, thereby reducing the temperature required to convert from face-centered cubic (fcc) to face-centered tetragonal (fct) phase by some 30-50 degrees C without additives. Annealing at 550 degrees C for 30 min converts the self-assembled nanoparticles into ferromagnetic nanocrystals with large coercivity, H(C) = 11.1 kOe. Reducing the fcc-to-fct (L1(0)) ordering temperature avoided particle coalescence and decreased the loss in particle positional order without compromising the magnetic properties, as is generally observed when additives are used.