6533b839fe1ef96bd12a5963

RESEARCH PRODUCT

Bio-inorganic Nanomaterials for Biomedical Applications (Bio-silica and Polyphosphate)

subject

description

Bio-silica represents the main mineral component of the sponge skeletal elements (siliceous spicules), while bio-polyphosphate (polyP), a multifunctional polymer existing in microorganisms and animals, acts, among others, as reinforcement for pores in cell membranes. These natural inorganic bio-polymers, which can be readily prepared, either by recombinant enzymes (bio-silica and polyP) or chemically (polyP), are promising materials/substances for the amelioration and/or treatment of human bone diseases and dysfunctions. Bone defects in human, caused by fractures/nonunions or trauma, have an increasing impact and have become a medical challenge in the present-day aging population. Frequently, those fractures require surgical intervention which ideally relies on autografts or suboptimally on allografts. Therefore, it is pressing and likewise challenging to develop bone substitution materials to heal bone defects. During the differentiation of osteoblasts from their mesenchymal progenitor/stem cells and of osteoclasts from their hemopoietic precursor cells, a lineage-specific release of growth factors and a trans-lineage homeostatic cross-talk via signaling molecules take place. Hence, the major hurdle is to fabricate a template that functions in a way mimicking the morphogenetic, inductive role(s) of the native extracellular matrix. In the last few years, two naturally occurring polymers that are produced by deep-sea sponges, the biogenic polyphosphate (polyP) and biogenic silica (bio-silica), have also been identified as promoting morphogenetic agents on both osteoblasts and osteoclasts. These polymers elicit cytokines which affect bone mineralization (hydroxyapatite (HA) formation). In this manner, bio-silica and polyP cause an increased release of BMP-2, the key mediator activating the anabolic arm of the HA-forming cells, and of RANKL. In addition, polyP inhibits the progression of the pre-osteoclasts to functionally active osteoclasts. Based on these findings, new bioinspired strategies for the fabrication of bone biomimetic templates have been developed applying 3D-printing techniques.