In vitro apatite-forming ability of hydrogels derived from sodium carboxymethylcellulose

Hydrogels able to form a bone-like hydroxyapatite (HAp) layer in the body environment are attractive materials as scaffolds for tissue engineering because they show osteoconductivity, i.e. bone-bonding property. In the present study, we synthesized hydrogels from sodium carboxymethylcellulose (sCMC), a water soluble polymer, through modification with a cross-linking agent, either ethylenediamine (EDA) or 3-aminopropyltriethoxysilane (APTES), followed by treatment with an aqueous solution containing calcium chloride aqueous solution. Formation of the bone-like HAp on the hydrogels was evaluated after immersion in a simulated body fluid (SBF). Hydrogels modified with the cross-linking agents EDA or APTES, and treated with 0.1 mol/dm³ of calcium chloride aqueous solution, formed a bone-like HAp layer on their surfaces after immersion in SBF for 3 days. Modification of organic polymers rich in carboxyl groups with APTES and CaCl₂ offers a new method to produce biomaterials with greater potential for forming HAp, which provides high affinity to living bone because the incorporation of silanol groups confers the high ability to induce HAp formation.