Multiphase calcium phosphate nanorods produced by microwave-assisted molten salt synthesis: Particle size RSM optimization

This study reports the statistical optimization using surface response methodology and genetic algorithms of an auto-ignited microwave molten salt synthesis of multiphase calcium phosphates, as these molecular mixtures integrate both osteoconductive and osteoinductive properties with a good capacity to control biodegradation. The molten salts containing phosphate and calcium precursors were heated in a time- and power-controlled microwave oven to obtain CaP nanopowders. X-ray diffraction, scanning electron microscopy, and infrared spectroscopy were used to characterize the chemical composition and morphology of the resulting samples. Cytocompatibility was measured using an MTT assay. Bioactivity was studied using simulated body fluids for up to 21 days. Results were analyzed using a response surface methodology coupled to a genetic algorithm that showed that the optimal time, microwave power, and amount of synthesis medium were 4.1 min, maximum power, and 4.5 g, respectively. This enabled the production of particles with average lengths and diameters of 1,300 and 120 nm, respectively. The obtained material obtained showed good cytocompatibility, bioactivity, and controllable dimensions.