Layer by layer deposition of hydroxyapatite onto the collagen matrix

Layer by layer (LbL) deposition is a useful method for deposition of many inorganic (including metals, oxides and phosphates) and organic (including polymers and proteins) components on a large range of substrates. The LbL deposition of hydroxyapatite (HA) onto a collagen matrix involves HA synthesis on the collagen matrix starting from electrically charged precursors such as Ca2+ and PO43− at a proper pH to precipitate the desired calcium phosphate.The LbL deposition process was continuously monitored in order to study the amount of HA deposited in each layer. The deposition of the first layers of HA was concluded to be highly influenced by the collagen matrix. When the collagen matrix is crosslinked with glutaraldehyde, the matrix structure is not modified during the deposition, and the porosity will decrease with the number of layers until saturation is reached. Following pore saturation, HA will be only deposited onto the mineralized collagen matrix surface. The obtained composite materials were characterized by XRD, SEM, DTA-TG and FTIR.