Vicente L. Kupfer

Synthesis of α-aminophosphonates using a mesoporous silica catalyst produced from sugarcane bagasse ash

A new green synthesis route is proposed for obtaining a mesoporous material using sugarcane bagasse ash (SCBA) as the silica source. The material obtained was denoted by SBA-16 and its mesostructure was characterized by low-angle X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption techniques. Sulfonic acid groups were introduced to the as-synthesized material, resulting in an acid catalyst denoted by SBA-16/SO3H. The catalytic activities of SBA-16 and SBA-16/SO3H were investigated in Kabachnik–Fields reactions, where α-aminophosphonate compounds were produced. The results show that both products can be considered as promising catalysts, where SBA-16/SO3H showed a slightly better performance than SBA-16.

Bionanocomposites based on mesoporous silica and alginate for enhanced drug delivery

This work reports the preparation, the characterization and the prednisolone release profile of biocompatible hydrogel nanocomposites containing mesoporous silica (SBA) and alginate as a biomaterial for enhanced drug delivery with reduced burst effect and improved mechanical properties. Such systems, which were prepared using specific SBA/alginate-crosslinking chemistry, exhibited interconnecting pore hybrid network owing to both mesoporous silica and hydrogel characteristics. Activated SBA was shown to be a determinant factor in inhibiting initial burst by nearly 90% and the drug was released with minimal burst kinetics. The nanoparticles reduced the movements of polymer chains, affecting macromolecular relaxation, and the distribution of mesoporous silica within the hydrogel made drug release into surrounding liquid less favorable. The proposed systems are biocompatible with human immortalized RWPE-1 prostatic epithelial cells. This report offers an approach of up-to-date interest for the development of advanced biomaterials for further physiological and pathological applications.

Synthesis and characterization of the polyaniline dopant Schiff base

The Schiff base, N-salicilidenoanilina was used as dopant to induce polymerization of aniline and thus preparing polyaniline (PAni). The different conditions of preparation, including Schiff base structure, and the dosage of acidity reaction medium, were investigated to discuss the influence of these conditions relative conductivity of the resulting samples. The products were also characterized by Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis), electrochemical impedance spectroscopy (EIE). The results showed the synthesis conditions play an important in the formation and the final properties of the polyaniline