Magnetically Multiplexed Heating of Single Domain Nanoparticles

Selective hysteretic heating of multiple collocated sets of single domain magnetic nanoparticles (SDMNPs) by alternating magnetic fields (AMFs) may offer a useful tool for biomedical applications. The possibility of magnetothermal multiplexing has not yet been realized, in part due to prevalent use of linear response theory to model SDMNP heating in AMFs. Predictive successes of dynamic hysteresis (DH), a more generalized model for heat dissipation by SDMNPs, are observed experimentally with detailed calorimetry measurements performed at varied AMF amplitudes and frequencies. The DH model suggests that specific driving conditions play an underappreciated role in determining optimal material selection strategies for high heat dissipation. Motivated by this observation, magnetothermal multiplexing is theoretically predicted and empirically demonstrated for the first time by selecting SDMNPs with properties that suggest optimal hysteretic heat dissipation at dissimilar AMF driving conditions. This form of multiplexing could effectively create multiple channels for minimally invasive biological signaling applications.