Formation and characterization of bioactive membranes obtained from natural polymers reinforced with biominerals

Abstract

Polymeric membranes, especially those consisting of biopolymers, are used in different application areas, for example, packaging and food coverage in food industry. Furthermore, we can find applications of these materials in medical area, in appropriate devices to be applied in vivo. The modification of these membranes through incorporation of inorganic particles is a strategy widely used in order to improve physical chemical characteristics desirable for application. In this way, materials formed by calcium carbonates and phosphates, minerals abundantly found in natural systems, and knowingly biocompatible, can be used for this application. So, the aim of this project is the development of new biopolymer membranes, which present combinations of organic and inorganic phases at the nanoscale, aiming the formation of bioactive hybrid materials with controllable properties and structures. These membranes must be bioactive stimulating hydroxyapatite growth in order to mimic bone tissue regeneration and have degradation rate compatible with the repair speed of this tissue. Special attention will be paid to the preparation and characterization of self-supporting membranes composed of collagen and biopolymers such as carrageenan, reinforced with phosphates and calcium carbonates. The incorporation of the inorganic phase in the organic matrix will be made through the exposure of hydrogels formed by the association of polymer chains with ions Ca2+, coming from solution of CaCl2, and PO43- from H3PO4, present in the aqueous solution in which the chosen biopolymers will be dissolved, in the atmosphere of NH3(g) and CO2(g) generated from the decomposition of (NH4)2CO3 in closed desiccator. Initially, hybrid biopolymer membranes are obtained using different percentages in weight of biopolymers varying the time of exposure to NH3 (g) and CO2 (g). Posteriorly, it will be characterized with respect to its composition is using vibrational spectroscopy by infrared-visible (FTIR) and microscopically by techniques scanning electron microscopy (SEM) and atomic force microscopy (AFM). The mineral phase deposited in these membranes is evaluated using X-ray diffraction (XRD). More, it will be characterized concerning to surface energy and wettability using contact angle measurements. The best results will be selected for osteoblast culture tests in vitro. The reabsorption and bioactivity of the samples will be study by immersing the membranes obtained after modification with biominerals fluid simulated body. It is intended to aid this project get potentially applicable materials such as bone tissue regenerating and accelerating the osteogenesis process.