Solution combustion synthesis (SCS) of theranostic ions doped biphasic calcium phosphates; kinetic of ions release in simulated body fluid (SBF) and reactive oxygen species (ROS) generation

Abstract

Theranostic ions offer suitable platforms for cancer theranostics; here, the effect of doping various amounts of theranostic ions (i.e., Sr²⁺, Fe²⁺, and Ti⁴⁺ ions) on the physicochemical properties and biological activities of calcium phosphates (CaPs) were investigated. The solution combustion synthesis (SCS) was conducted at different amounts of ions (i.e., = 0.1, 0.25, 0.5 mol). Desirable physicochemical properties were obtained in doped samples with 0.1 mol of ions. The particle size of the Sr, Fe, and Ti-doped samples was decreased from 68 to 39, 24, and 29 nm, respectively. The surface charge of the mentioned samples was changed from -20 to -24, -28, and -25 mV, respectively. Besides, the specific surface area of the mentioned samples was significantly increased from 38 to 79, 65, and 106 m²/g, respectively. It was found that bioactivity of doped CaPs improved ~95%, which relied on the high adsorption and desorption rate of Ca²⁺ ions in the simulated body fluid (SBF). The in vitro cell-based results demonstrate the potent effect of CaPs and theranostic ions doped CaPs on the reactive oxygen species (ROS) generation. In the presence of CaPs, the intracellular ROS generation is increased by about 60%. Besides, the intracellular ROS generation is improved in Sr²⁺, Fe²⁺, and Ti⁴⁺ ions doped CaPs by about 66, 64, and 68%. As a result of the high generation of ROS, the bone nodule formation of cell treated CaPs and theranostic ions doped CaPs is improved 25%-37%. Finally, it can be concluded that the use of the SCS approaches for doping of theranostic ions causes well-physicochemical properties and high biological activities.

Keywords: Bioactivity; Bone tissue engineering; Calcium phosphates; Reactive oxygen species; Solution combustion synthesis; Theranostic ion.