In
this work, we report the synthesis of hydrophilic and surface-functionalized
superparamagnetic iron oxide nanoparticles (SPIOs) to utilize them
as nanomedicines for treating liver cancer via magnetic fluid hyperthermia
(MFH)-based thermotherapy. For this purpose, initially, we have synthesized
the SPIOs through co-precipitation/thermolysis methods, followed by
in situ surface functionalization with short-chained molecules, such
as 1,4-diaminobenzene (14DAB), 4-aminobenzoic acid (4ABA) and 3,4-diaminobenzoic
acid (34DABA) and their combination with terephthalic acid (TA)/2-aminoterephthalic
acid (ATA)/trimesic acid (TMA)/pyromellitic acid (PMA) molecules.
The as-prepared SPIOs are investigated for their structure, morphology,
water dispersibility, and magnetic properties. The heating efficacies
of the SPIOs are studied in calorimetric MFH (C-MFH) with respect
to their concentrations, surface coatings, dispersion medium, and
applied alternating magnetic fields (AMFs). Although all of the as-prepared
SPIOs have exhibited superparamagnetic behavior, only 14DAB-, 4ABA-,
34DABA-, and 4ABA-TA-coated SPIOs have shown higher magnetization
values (Ms = 55–71 emu g–1) and good water dispersibility. In C-MFH studies, 34DABA-coated
SPIO-based aqueous ferrofluid (AFF) has revealed faster thermal response
to the applied AMF and reached therapeutic temperature even at the
lowest concentration (0.5 mg mL–1) compared with
14DAB-, 4ABA-, and 4ABA-TA-coated SPIO-based AFFs. Moreover, 34DABA-coated
SPIO-based AFF has exhibited high heating efficacies (i.e., specific
absorption rate/intrinsic loss power values of 432.1 W gFe–1/5.2 nHm2 kg–1 at
0.5 mg mL–1), which could be mainly due to (i) enhanced
π–π conjugation paths of surface-attached 34DABA
coating molecules because of intrafunctional group attractions and
(ii) improved anisotropy from the formation of clusters/linear chains
of the SPIOs in ferrofluid suspensions, owing to interfunctional group
attractions/interparticle interactions. Moreover, the 34DABA-coated
SPIOs have demonstrated (i) very good cytocompatibility for 24/48
h incubation periods and (ii) higher killing efficiency of 61–88%
(via MFH) in HepG2 liver cancer cells as compared to their treatment
with only AMF/water-bath-based thermotherapy. In summary, the 34DABA-coated
SPIOs are very promising heat-inducing agents for MFH-based thermotherapy
and thus could be used as effective nanomedicines for cancer treatments.
