Gadolinium and Polythiophene Functionalized Polyurea Polymer Dots as Fluoro-Magnetic Nanoprobes

A rapid and one-pot synthesis of poly 3-thiopheneacetic acid (PTAA) functionalized polyurea polymer dots (Pdots) using polyethyleneimine and isophorone diisocyanate is reported. The one-pot mini-emulsion polymerization technique yielded Pdots with an average diameter of similar to 20 nm. The size, shape, and concentration of the surface functional groups could be controlled by altering the synthesis parameters such as ultrasonication time, concentration of the surfactant, and crosslinking agent, and the types of isocyanates utilized for the synthesis. Colloidal properties of Pdots were characterized using dynamic light scattering and zeta potential measurements. The spherical geometry of Pdots was confirmed by scanning electron microscopy. The Pdots were postfunctionalized by 1,4,7,10 tetraazacyclododecane-1,4,7,10-tetraacetic acid for chelating gadolinium nanoparticles (Gd3+) that provide magnetic properties to the Pdots. Thus, the synthesized Pdots possess fluorescent and magnetic properties, imparted by PTAA and Gd3+, respectively. Fluorescence spectroscopy and microscopy revealed that the synthesized dual-functional Gd3+-Pdots exhibited detectable fluorescent signals even at lower concentrations. Magnetic levitation experiments indicated that the Gd3+-Pdots could be easily manipulated via an external magnetic field. These findings illustrate that the dua- functional Gd3+-Pdots could be potentially utilized as fluorescent reporters that can be magnetically manipulated for bioimaging applications.

Automated summary

A rapid one-pot synthesis of PTAA functionalized polyurea polymer dots was achieved, and the resulting dots were further functionalized with gadolinium nanoparticles for fluorescence and magnetic properties. The synthesized dual-functional Gd3+-Pdots showed detectable fluorescent signals even at lower concentrations and could be easily manipulated via an external magnetic field.