Hydroxyapatite formation on cellulose cloth induced by citric acid

Hydroxyapatite (HAp) formation on cellulose cloth with the aid of citric acid was investigated. The cellulose cloths were soaked in simulated body fluid (SBF) solutions (1.5 SBF) with ion concentrations 1.5 times that of SBF (1.0 SBF) with and without citric acid and carbonate containing HAp crystals were found to form only in the 1.5 SBF solution that contained citric acid. The results were explained in terms of hydrogen bonding of citric acid to the cellulose cloth and its chelating ability of calcium ions. Practical application may involve the inclusion of citric acid in the 1.5 SBF solution to promote formation of HAp on previously bioinert cellulose cloth.