Synthesis of hyperbranched poly(amidoamine) conjugated silica (HBPcS) particles and their application to colorimetric detection of cadmium ion

Hyperbranched poly(amidoamine) conjugated silica (HBPcS) particles were synthesized by grafting poly(amidoamine) dendrimers on multiple-functional hybrid silica (MHS) particles containing three different organosilane functional groups. Due to advantageous combination of dendrimers, with ample and controlled amount of amine groups, and monodisperse and stable MHS particles from simple one-pot synthesis, the HBPcS particles can serve as multifunctional platforms for various applications. The growth of the amine functional groups of the HBPcS particles with the generation number was confirmed by monitoring the amide peaks in IR spectra as well as indirectly by monitoring the amount of the molecules that are bound to the functional groups. As a proof of principle, colorimetric sensors for Cd ions were prepared by employing the HBPcS particles and organic Cd ion sensing molecules. Notably, the sensor particles from HBPcS particles of different generations showed different detection ranges due to the increase in the amount of amine functionalities by grafting processes.