Controlled release of 5-fluorouracil to melanoma cells using a hydrogel/micelle composites based on deoxycholic acid and carboxymethyl chitosan.

5-Fluorouracil (5-FU) is an antimetabolite drug widely used for the treatment of skin cancer. Despite its proven efficacy in treating malignancies, its systemic administration is limited due to severe side effects. To address this issue, topical delivery of 5-FU has been proposed as an alternative approach for the treatment of skin cancer, however, the poor permeability of 5-FU through the skin is still a challenge. Here, we introduced a pH-responsive micellar hydrogel system based on deoxycholic acid micelle (DCA Mic) and carboxymethyl chitosan hydrogel (CMC Hyd) to enhance 5-FU efficacy against skin cancer and reduce its systemic side effects by improving its delivery into the skin. The properties of the Mic/Hyd system were determined by Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta sizer, atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Drug release studies showed pH-dependent properties of the Hyd. The final formulation was demonstrated to have enhanced anticancer activity than 5-FU against the growth of melanoma cells. The 5-FU@Mic-Hyd could be a promising delivery platform with enhanced efficacy in the management of skin cancer without systemic toxicity.

Photocurrent generation by adsorption of two main pigments of Halobacterium salinarum on TiO2 nanostructured electrode.

Dye-sensitized solar cells (DSSCs), which are proposed as a substitute for silicon crystalline solar cells, have received considerable attention in the recent decade. They could be produced from inexpensive materials through low-cost processes. In the current work, a bio-sensitized solar cell is designed using abundant, cheap, and nontoxic materials. Bacteriorhodopsin and bacterioruberin are two natural biomolecules found in the cytoplasmic membrane of Halobacterium salinarum. These two pigments were immobilized on nanoporous titanium dioxide films successfully and employed as molecular sensitizers in DSSC with efficient photocurrent generation. The photovoltaic performance of DSSCs based on bacteriorhodopsin and bacterioruberin sensitizers was investigated. Under AM1.5 irradiation a short-circuit current of 0.45 mA cm(-2) , open circuit voltages of 0.57 V, fill factor of 0.62, and an overall energy conversion efficiency of 0.16% are achieved by employing a mixture of biomolecules as a sensitizer.

Light harvesting and photocurrent generation by nanostructured photoelectrodes sensitized with a photosynthetic pigment: a new application for microalgae.

Here in this study, successful conversion of visible light into electricity has been achieved through utilizing microalgal pigments as a sensitizer of nanostructured photo-electrode of dye-sensitized solar cells (DSSCs). For the first time, photosynthetic pigments extracted from microalgae grown in wastewater is employed to imitate photosynthesis process in bio-molecule-sensitized solar cells. Two designs of photoanode were employed: 10 µm nanoparticular TiO2 electrode and 20 µm long self-ordered, vertically oriented nanotube arrays of titanium dioxide films. Microalgal photosynthetic pigments are loaded on nanostructured electrodes and their photovoltaic performances have been investigated. To optimize the performance of solar cell, the time course of dye loading on the nanocrystalline TiO2 films is investigated. The performance of the cells is characterized by measuring the current-voltage (I-V) curves under AM1.5 (100 mW cm(-2)) irradiation condition. The highest efficiency of around ∼ 1%, quite comparable to green plants, is found for sensitizer-loading time of 1h.