Roles of trifluoroacetic acid, acetic acid and their salts in the synthesis of helical mesoporous materials

Helical mesoporous materials have attracted much attention due to their potential applications in catalysis and chiral recognition. In this paper, we have systematically studied the influence of trifluoroacetic acid, acetic acid and their salts on the synthesis of helical mesoporous materials in the presence of a cationic surfactant cetyltrimethylammonium bromide (CTAB) as a template. Results show that helical mesostructures can be successfully synthesized when CF(3)COO(-) anions were used as additives with an additive/CATB molar ratio (R) range of 0.1-0.375 for the CF(3)COOH/CTAB templating system and a relatively wider R range of 0.1-0.5 for the CF(3)COONa/CTAB templating system, which can be attributed to the influence of pH caused by the acid- or salt-form of additives. The pitch sizes of the helical mesostructures can be finely controlled by varying the additive/CTAB ratio. The results indicate that in order to synthesize helical mesostructures in a broad range of additive/CTAB ratios, the perfluorinated salt with a short fluorocarbon chain should be used. Our synthesis strategy can be used for the fabrication of helical mesostructured porous materials with adjustable pore and helical pitch sizes, which are important in their potential applications

Advances and challenges in retinoid delivery systems in regenerative and therapeutic medicine

Retinoids regulate a wide spectrum of cellular functions from the embryo throughout adulthood, including cell differentiation, metabolic regulation, and inflammation. These traits make retinoids very attractive molecules for medical purposes. In light of some of the physicochemical limitations of retinoids, the development of drug delivery systems offers several advantages for clinical translation of retinoid-based therapies, including improved solubilization, prolonged circulation, reduced toxicity, sustained release, and improved efficacy. In this Review, we discuss advances in preclinical and clinical tests regarding retinoid formulations, specifically the ones based in natural retinoids, evaluated in the context of regenerative medicine, brain, cancer, skin, and immune diseases. Advantages and limitations of retinoid formulations, as well as prospects to push the field forward, will be presented.Cerebrovascular Disease Grant and L’Oréal-UNESCO Portugal for Women in Scienc