Preparation of succinylated cellulose membranes for functionalization purposes.

The anhydroglucose chains of cellulose possess hydroxyls that facilitate different chemical modification strategies to expand on, or provide new applications for membranes produced by the bacteria Gluconacetobacter xylinus. Conjugation with biomolecules such as proteins, especially by the amine groups, is of great value and interest for the production of biomaterial derivatives from bacterial cellulose. To assist in these modifications, cellulose was succinylated in order to prevent steric hindrance and to create an attachment point for conjugation. Bacterial cellulose membranes were first treated in dichloromethane and reacted with succinic anhydride through a series of conditions. The membrane structure remained intact after these first processes and the product was confirmed by Infra-Red spectroscopy and solid state nuclear magnetic resonance and characterized by X-ray diffraction, thermogravimetry and atomic force microscopy. Hydrolyzed collagen was used as a model protein of interest to be conjugated to these membranes, which furnished a biomaterial functionalized over its surface.

Revealing the Binding Process of New 3-Alkylpyridine Marine Alkaloid Analogue Antimalarials and the Heme Group: An Experimental and Theoretical Investigation.

Synthetic 3-alkylpyridine marine alkaloid (3-APA) analogues have shown good antimalarial activity against Plasmodium falciparum. However, despite their structural originality, their molecular target was unknown. Herein, we report a proposal for the antimalarial mechanism of action of 3-APA analogues through interference with the process of hemozoin (Hz) formation. The interaction between 3-APA analogues and heme groups was investigated employing an in silico approach and biophysical techniques such as ultraviolet-visible light (UV-vis) titration and electrospray ionization-mass spectrometry (ESI-MS). The in silico approach was performed based on pure ab initio electronic structure methods in order to obtain insights at the molecular level concerning the binding process of antimalarial drugs at their target site, the heme group. In silico results showed that the formation of heme:3-APA complexes at a molecular ratio of 2:1 are more stable than 1:1 complexes. These results were further confirmed by experimental techniques, such as UV-vis and high-resolution mass spectrometry (ESI-TOF), for two of the most active 3-APA analogues.