Power electronic drives for magnetically triggered gels

A Magnetically Triggered Composite Membrane for On-Demand Drug Delivery

“…Figure 2b shows the magnetic triggering of the composite membrane. The magnetic nanoparticles embedded in the membrane heated inductively when subjected to an external oscillating magnetic field, heating previously attributed to power absorption and subsequent magnetic relaxation of single-domain nanoparticles 45 . At the applied magnetic frequency and field amplitude, the water inside the semiadiabatic flow cell heated from 37°C to ~42°C over the course of ~10 minutes, at which point the temperature reached steady state.…”

“…The magnetic nanoparticles embedded in the membrane heated inductively when subjected to an external oscillating magnetic field, heating previously attributed to power absorption and subsequent magnetic relaxation of single-domain nanoparticles. 47 At the applied magnetic frequency and field amplitude, the water inside the semiadiabatic flow cell heated from 37 °C to ∼42 °C over the course of ∼10 min, at which point the temperature reached steady state. Heat generated by mag-netite induction heating was transferred to the adjacent thermosensitive nanogels, causing the nanogels to shrink and permit drug diffusion out of the device.…”

Nonresonant and Resonant Frequency-Selectable Induction-Heating Targets

“…Traditionally, induction heating has been used for applications that include cooking [4], as well as various industrial processes such as melting, annealing, and hardening [5]. However, in the past, induction heating was also successfully used to trigger single gel polymers without physical contact [6]. While ongoing research in the area of induction heating ranges from coil design [7] and load modeling [8] to control algorithms [9], the majority of these applications deal with single loads.…”

“…6(b) for this example. Because of the identical coupling and the even spacing in break-point frequencies, each target experiences power dissipation of at least 2.6 times more than any of the remaining targets when driven at its break-point frequency-as suggested by (6) and (7). From these equations, it is apparent that the degree of achievable preferential heating is modest.…”