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Abstract

Calcium phosphate growth on chitin phosphorylated fibres was studied using scanning electron microscopy and energy dispersive X-ray analysis (SEM, EDX), micro-Fourier transform infrared spectroscopy (FTIR), and solid state magic angle spinning nuclear magnetic resonance (MAS NMR) techniques. The C6 chemical shift positions of 13C MAS NMR in the chitin fibres phosphorylated using urea and H3PO4 are obvious indicating that phosphorylation takes place not in the C1 but in the C6 region. Micro-FTIR and 31P MAS NMR suggested that ammonium hydrogen phosphate formed during the phosphorylation procedure. Chitin fibres phosphorylated using urea and H3PO4 and then soaked in saturated Ca(OH)2 solution at ambient temperature, which lead to the formation of thin coatings formed by partial hydrolysis of the PO4 functionalities, were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5xSBF solution for as little as one day. The thin layer after Ca(OH)2 treatment functioned as a nucleation layer for further calcium phosphate deposition after soaking in 1.5xSBF solution. EDX-measured Ca : P ratios of the coatings of Ca(OH)2-treated phosphorylated chitin in 1.5xSBF solution suggested that calcium-deficient apatite was formed.

Biomimetic Systems for Hydroxyapatite Mineralization Inspired By Bone and Enamel

“…It is biodegradable and nontoxic and can be isolated from the shells of crabs, lobsters, and other crustaceans. Chitin can be phosphorylated using H 3 PO 4 and urea 221. Soaking this acidic polymer with saturated Ca(OH) 2 solutions resulted in the growth of a thin layer of calcium phosphate.…”

Cellulose phosphates as biomaterials. I. Synthesis and characterization of highly phosphorylated cellulose gels

“…Synthetic calcium phosphates generally induce the formation of an apatite layer in simulated plasma solutions. Some other synthetic biomaterials have also shown the capability of inducing the formation of an apatitic mineral, namely polymers containing phosphate functionalities,35–38 including phosphorylated cellulose derivatives 39–41. However, only low degrees of phosphorylation were used because of the lack of techniques that would allow highly phosphorylated products to be obtained.…”

Selective monophosphorylation of chitosan via phosphorus oxychloride

“…For example, phosphorylated chitosan effectively complexes Ca 2+ to enhance tooth enamel remineralization and prevent future acid-catalyzed demineralization. 26,41 We examined the Ca 2+ chelation properties of P-chitosan by measuring total calcium chelation as a function of phosphorylation degree (Table 3). P-chitosan chelation was compared to that observed from control chitosan (i.e., no phosphorylation).…”