Abstract
Amine and carboxylic acid-bifunctionalized iron oxide nanoparticles with robust silane linkages to the nanoparticle surface were prepared with a versatile direct grafting protocol. The contrast in chemistry of these two groups was highlighted by attaching a fluorophore, Rhodamine B isothiocyanate (RITC) onto the amine group and an antibody (EPCAM - epithelial cell adhesion molecule) onto the carboxylic acid groups. The iron oxide core and the RITC tags provide the MRI-fluorescent bi-modal imaging capability. The EPCAM antibody is specific to a protein ubiquitously expressed on the epithelial cell surface. These bifunctionalized nanoparticles target and then undergo facilitated uptake into pancreatic cancer cells (Panc-1) in a time course-monitored controlled study. The integrated optical imaging properties of these magnetic nanoparticles were utilized to monitor the interaction of the nanoparticles with the EPCAM receptors on the cell membrane of the Panc-1 cells. The time-course of the uptake for the targeted and the control particles by the cells was followed allowing the localization within the cell and the impact of particle functionalization to be identified. This system is a candidate for further development as a multi-modular imaging, diagnostic and delivery tool.