Current Development in Biomaterials-Hydroxyapatite and Bioglass for Applications in Biomedical Field: A Review

Abstract

Inorganic biomaterials, including different types of metals and ceramics are widely used in various fields due to their biocompatibility, bioactivity, and bioresorbable capacity. In recent years, biomaterials have been used in biomedical and biological applications. Calcium phosphate (CaPs) compounds are gaining importance in the field of biomaterials used as a standalone material or in more complex structures, especially for bone substitutes and drug delivery systems. The use of multiple dopants into the structure of CaPs compounds can significantly improve their in vivo and in vitro activity. Among the general information included in the Introduction section, in the first section of this review paper, the authors provided a background on the development of hydroxyapatite, methods of synthesis, and its applications. The advantages of using different ions and co-ions for substitution into the hydroxyapatite lattice and their influence on physicochemical, antibacterial, and biological properties of hydroxyapatite are also presented in this section of the review paper. Larry Hench's 45S5 Bioglass^®, commercially named 45S5, was the first bioactive glass that revealed a chemical bond with bone, highlighting the potential of this biomaterial to be widely used in biomedicine for bone regeneration. The second section of this article is focused on the development and current products based on 45S5 Bioglass^®, covering the historical evolution, importance of the sintering method, hybrid bioglass composites, and applications. To overcome the limitations of the original biomaterials, studies were performed to combine hydroxyapatite and 45S5 Bioglass^® into new composites used for their high bioactivity and improved properties. This particular type of combined hydroxyapatite/bioglass biomaterial is discussed in the last section of this review paper.

Keywords: 45S5 Bioglass®; bioceramics; biomaterials; hydroxyapatite.

Figure 1

Schematic diagram of different categories of biomaterials and their applications [8].

Figure 2

The molecular structure of hydroxyapatite—unit cell perspective of hexagonal crystal structure with P6₃/m symmetry [36,37].

Figure 3

Periodic table of elements—each element has a corresponding color (yellow, green, blue, pink, and orange) which suggests the total number of its literature reports. The only adventitious element is carbon because most HAp crystals precipitated under the atmospheric conditions contain finite amounts of the carbonate ion. For this statistic, Scopus and Google Scholar search engines were used [66].

Figure 4

Schematic representation of synthesis methods for doped hydroxyapatite and the effect of the doping ions on anticancer, antibacterial, and osteogenesis properties [90].