Fig. 21. Representative optical microscopy images of MCF-7 cells illustrating morphological alterations following magnetothermal treatment of FG@SAPD core–shell DOX-loaded nanoparticles under an alternating magnetic field (VK10 ×10 magnification). Cells were exposed to AMF-induced heating at 45 °C for (a) 5 min and (b) 10 min, and at 55 °C for (d) 5 min and (e) 10 min. Control groups include cells incubated with FG@SAPD for (c) 5 min and (f) 10 min in the absence of AMF under normothermic conditions (37 °C).