The preparation of polypyrrole/Fe3O4 nanospheres by a facile mini-emulsion polymerization method is investigated using poly(ethylene glycol), poly(ethylene oxide), poly(vinyl alcohol), and hyaluronic acid as, surfactants. Hyaluronic acid is deemed the most suitable surfactant since it results in well-dispersed nanospheres of 80-100 nm, and offers the advantages of biocompatibility, cell adhesive property, and the availability of functional groups for attachment of other molecules. These polypyrrole/Fe3O4 nanospheres are magnetic and can be further functionalized with a cancer antibody, herceptin. Our results show that this combination of hyaluronic acid and herceptin results in high specific uptake of the nanospheres by cancer cells.