“9.61x6.69” b2815 Tissue Engineering and Nanotheranostics
Magnetic Nanohybrids for Magnetic Resonance Imaging 133
Fig. 21. (a1), (a2) T 1 and T 2 -weighted in vivo MR images of MCF-7 tumor-
bearing nude mice before and after 2 h of injection (100 mL FA–Gd–Si–TiNPs
(500 mg/mL) in PBS by intratumoral injection) and (a3) photodynamic therapy
effect of various nanoparticles on tumor size. (b) In vivo T 1 -weighted MR images of
a 4T1-tumor bearing mouse after intravenous injection of UCMSNs at selected time
points: (a) 0 min; (b) 5 min; (c) 10 min; (d) 15 min. Reprinted with permission from
Refs. 52 and 53.
images (Figs. 21(b1)–21(b4) taken at different intervals of time. The
MRI results showed that signal intensity in tumor was increased
by time period and accumulated at tumor area due to enhanced perme-
ability and retention effect (EPR) of tumors. Moreover, in vivo
therapeutic effect of UCMSNs–HP on mice 4T 1 tumor is shown in
Figs. 21(b5)–21(b8). UCMSNs–HP–Dtxl + RT + NIR showed signifi-
cant influence to kill the tumor which they also observed in histological
examination after sacrifice into the mice. Hence, these MRI and PDT
results showed that a UCMSNs–HP material has potential against
cancer activity.
Another excellent and first report was published by Wu et al.^75
They synthesized Fe 3 O 4 –TiO 2 Janus hybrid nanoparticles for
T 2 -weighted MRI contrast agent and PDT applications. The longitu-
dinal and transverse relaxivities (r1 and r2) of Fe 3 O 4 –TiO 2 magnetic
nanohybrids with various concentrations were 1.444 mM^1 s^1 and
