Impact of Photothermal and Magnetomechanical Treatments with Au-Fe Layered Microdisks on Cell Viability

Hybrid magnetic–plasmonic nanoparticles offer a promising platform for cancer therapy by combining localized photothermal heating with nanoscale mechanical stimulation under remote laser irradiation and low-frequency alternating magnetic fields. However, the therapeutic potential of combining these effects remains insufficiently explored. In this study, we investigated the individual and combined effects of photothermal therapy (PTT) and magnetomechanical therapy (MMT) on the viability of Huh7 hepatocarcinoma cells in vitro using two types of layered Au–Fe microdisks (~1000 nm in diameter) with different layer sequences, i.e., Au(10)/Fe(70)/Au(10) (AFA) and Fe(50)/Au(10)/Fe(50) (FAF), where the values in parentheses denote the layer thicknesses in nanometers. The photothermal conversion efficiencies of the AFA and FAF microdisks in agarose were 35% and 53%, respectively, exceeding the values measured in aqueous solutions. After 24 h of incubation, both types of microdisks exhibited low intrinsic cytotoxicity up to concentrations of 100 µg/mL, at which the cell viability was reduced by no more than 7%. Application of either PTT or MMT enhanced cytotoxicity for both microdisk types. PTT was more effective for AFA microdisks, resulting in 29% cell death, whereas MMT showed greater efficacy for FAF microdisks, inducing 17% cell death. Notably, simultaneous PTT and MMT produced the strongest and synergistic therapeutic effect, leading to approximately 50% cell death. These findings demonstrate the potential of hybrid Au–Fe microdisks as multifunctional agents for combined photothermal and magnetomechanical cancer therapy.