Multifunctional calcium carbonate microparticles: Synthesis and biological applications

Multifunctional composites based on calcium carbonate (CaCO3) spherical microparticles stabilized through the embedding of CdSe/ZnS/SiO2 nanoparticles into surface pores were fabricated. The stabilization of the vaterite polymorph of CaCO3 through nanoparticles embedding was necessary to generate a spherical, porous morphology of the microparticles. The CdSe/ZnS quantum dots were obtained and dispersed in aqueous solution after coating them with a silica shell via a reverse microemulsion approach. Green and red-emitting CaCO3-CdSe/ZnS/SiO2 microcomposites were analyzed via confocal laser-scanning fluorescence microscopy were to demonstrate their potential for imaging applications. The acetylcholinesterase (AChE) enzyme was immobilized into the pores of the spherical CaCO3-CdSe/ZnS/SiO2 microcomposites and the resulting hybrid material was used as a platform for the design of a pesticide biosensor. The detection limit for the paraoxon pesticide in aqueous solutions was determined to be of 4.6 nM.