One-pot synthesis of injectable methylcellulose hydrogel containing calcium phosphate nanoparticles

Abstract

A thermo-sensitive hydrogel based on calcium phosphate nanoparticles was prepared using a novel one-pot method in which added precursor salts induced a salt-out effect in the methylcellulose (MC) solution. The calcium phosphate nanoparticles were synthesized in situ from precursor ions (Ca²⁺ and HPO₄^2-) in the hydrogel, and residual ions (HPO₄^2- and Cl^-) in the formation of the nanoparticles decreased the gelation temperature of the MC solution. This one-pot synthesis was an effective way to streamline the previous multi-step process and to easily prepare a thermo-sensitive hydrogel containing bioactive nanoparticles. The thermo-sensitive properties of different concentrations of MC hydrogels were characterized by a rheometer and infrared (IR) spectroscopy. The gelation behavior of MC according to the addition of various salts was monitored by rheometer. With respect to a selected concentration and precursor, the structure of the MC hydrogel containing calcium phosphate nanoparticles was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and IR.

Keywords: Calcium phosphate nanoparticles; In situ formation; Injectable gel; Methylcellulose; Thermo-sensitive hydrogel.