Preparation and characterization of gelatin microgels by calcium carbonate template

Abstract

The following work was focused in the study, preparation and characterization of gelatin microgels based in the structure of a porous CaCO3 template in its polymorphs form vaterite (spherical). The importance of this research is because the template is cheap, non-toxic and easy to produce and to decompose by EDTA at basic pH. The template was prepared by mixing the same volume of salts, Na2CO3 and CaCl2. It was characterized by optical microscopy, scanning electron microscopy (SEM), nitrogen sorption, Thermogravimetric Analysis (TGA) and zeta potential. The obtained results demonstrate that the template has a particle size of about 4 μm with a wide distribution of mesopores. The microgel has been obtained by two ways by using the CaCO3 template. The first one is the use of physisorption (physical adsorption) and the second one is the co-precipitation. Only the second way provide quantitative results. As a gelatin cross-linker, genipin and transglutaminase have been chosen by its nature, biocompatibility and low toxicity. Genipin has given the best results because transglutaminase could be more influenced by pH and may contain partial charges. Finally, gelatin microgels have been characterized by SEM, optical microscopy, TGA and Z potential. Microgels cross-linked with genipin have a size distribution similar to CaCO3 microparticles and a slight negative charge in solution