Review on Biological Synthesis of Nano-Hydroxyapatite and Its Application in Nano-Medicine

Hydroxyapatite (HA) has many applications in medicine, dentistry, diagnosis, drug delivery systems, sewage treatment, bone remodeling, concentrating bacteria, covering implants, and antibacterial activity. Despite the numerous current applications of calcium phosphate compounds, particularly HA, their producing methods are being investigated to find the best processes. Several chemical and biological methods are used in calcium phosphate compounds synthesis. Researches have shown that compared to micrometer models, nanostructured HA has higher mechanical features and better biocompatibility in the human body. These properties optimize when nanometer components of HA are in similar size and shape with the least agglomerations. Biomineralization by microorganisms, which is a bacterial route, is a recent HA synthesis method. This paper is a review on the biosynthesis of HA emphasizing microbial methods. In this method, some bacteria and mold could be used in the nanometer production of HA. This type of bacterium commonly has a high amount of alkaline phosphatase enzymes. Desirable similarity to natural HA in the human body is the noticeable features of bacterial HA. Uniformity in the shape and size of synthesized particles that have the same crystallization is of other merits. Producing bacterial HA is easily reachable, one-step, inexpensive, harmless, and with high purity, and contrary to chemical synthesis, does not need heat treatment and precise pH adjustment.