One application of SPMR is the detection of disease and cancer. This is accomplished by functionalizing the NP with biomarkers, including cell antibodies (Ab). The functionalized NP+Ab may be subsequently attached to cells targeted by the biomarker in cell cultures, blood and marrow samples, as well as animal models.
A variety of biochemical procedures are used to conjugate the NP with the biomarker. The resulting NP+Ab are either directly mixed with incubated blood or diseased cells, or injected into animals. Following injection the functionalized NP reside in the bloodstream until encountering cells that are specific to the biomarker attached to the Ab.
Conjugation of NP with Ab followed by attachment to cells is accomplished by identifying particular cell lines expressing varying levels of the Ab by flow cytometry. The Ab is conjugated to the superparamagnetic iron oxide NP by different methods including the carbodiimide method. The conjugated NP+Ab are then incubated with the cell lines and may be examined by transmission-electron microscopy (TEM) to confirm that the NP+Ab are attached to the cells. Other methods to determine whether NP are present on the surface of the cell are confocal microscopy, Prussian blue histochemistry, and SPMR. The resulting carboxylate functionality of the polymer-encapsulated NPs by this method allows conjugation of amine groups on the Ab to the carboxylate anions on the surface of the NPs using standard two-step EDC/NHS chemistry.