Bentonite Clays for Therapeutic Purposes and Biomaterial Design

Abstract

Bentonite is a natural clay composed mainly of montmorillonite with other associated minerals such as feldspar, calcite and quartz. Owing to its high cation exchange, large surface area and ability to form thixotropic gels with water and to absorb large quantities of gas, it presents a large medicinal application. This review focuses on the promising potential of bentonite clays for biomaterial design and for therapeutic purposes. PubMed, ACS publications and Elsevier were searched for relevant papers. We have also evaluated the references of some pertinent articles. Healing properties of bentonite are derived from the crystalline structure of the smectite group, which is composed of two octahedral alumina sheets localized between two tetrahedral silica sheets. This structure is behind the ability to intercalate cationic bioactive agents and undergoes interaction with various toxic species and exchanging in return species such as Fe3+, Cu2+, Al3+ Ca2+ or Na+, presenting antibacterial activity and providing essential minerals to the body. Furthermore, due to to its layered structure, bentonite has wide application for the design of biomaterials providing, thus, the stability of bioactive agents and preventing them from aggregation. Numerous publications have cited bentonite extensive applications as an alternative and complementary treatment for numerous health conditions as a detoxifying agent and for the preparation of several bionanocomposites.