Preparation and characterization of sodium alginate/phosphate-stabilized amorphous calcium carbonate nanocarriers and their application in the release of curcumin

Phosphate-stabilized amorphous calcium carbonate (ACCP) has excellent biocompatibility, bioactivity, and biodegradability, and can be easily synthesized and stored. However, unmodified ACCP, as a controlled drug release carrier, decomposes rapidly in an acidic environment and highly depends on the system's pH value, which can not meet the need for long-term release of active substances, thus limiting its application scope. To realize the specific pH responsiveness of ACCP nanoparticles, we designed and synthesized monodisperse sodium alginate/ACCP (Alginate/ACCP) composite nanoparticles in this paper. After ultrasonic treatment, nanoparticles with an average particle size less than 200 nm could form stable water dispersion that could be dispersed for up to 10 d. Based on the specific pH sensitivity of sodium alginate, the drug-controlled release performance of composite nanoparticles and the therapeutic effect of drug-loaded nanoparticles on A549 cancer cells were studied. The results indicated that under the same pH condition, the curcumin (Cur) release rate of composite nanoparticles gradually decreased with sodium alginate addition. When the dosage of sodium alginate was 1.0 mg ml−1, the cumulative drug release rate of nanoparticles in 40 h was only about 35%. Besides, the drug-loaded nanoparticles showed the excellent killing ability of cancer cells, and the survival rate of cancer cells decreased in a concentration-dependent manner. Therefore, through reasonable optimization design, we can synthesize composite nanoparticles with excellent sustained-release properties to provide a new strategy for cancer cells' long-term treatment.