Table 2. Physico-chemical properties of targeted SPIO nanoparticles.

Dopant	Ligand	Pre-Conjugation Size (nm)	Post-Conjugation Size (nm)	Pre Conjugation Zeta (mV)	Post Conjugation Zeta (mV)	r1 (mM−1s−1)	r2 (mM−1s−1)
Er	None	27.00	33.54	−5.63	−10.01	6.2	262.9
Ho	HER2-Affibody	28.07	33.47	−4.47	−10.53	10.3	135.2
Sm	RGD	27.77	35.57	−6.09	−6.48	9.2	158.5
Gd	LDS	29.07	34.84	−5.77	−8.61	8.1	172.6