Magnetothermal stimulation is key in biomedical applications like tumor ablation, drug delivery, and regenerative therapies. A common method involves injecting magnetic particles that heat under an alternating magnetic field (AMF). However, uncontrolled heating can damage healthy tissues. Maintaining temperatures below 45 °C is critical. Using materials with a Curie temperature (Tc) near this limit offers a self-regulating solution, as magnetization—and thus heating—drops sharply at Tc. This study explores Mn0.65Fe1.30P0.65Si0.37 (MCM), a magnetocaloric material composed of non-toxic elements and featuring a tunable Tc. It is engineered to exhibit a Tc of 43 °C, close to the safe physiological threshold. MCM particles are encapsulated in a wax matrix to form a composite that responds to AMF exposure. Heat generated by MCM particles triggers the wax phase transition, while the obtained Tc enables the composite to achieve self-limiting thermal regulation under magnetic field exposure. Biocompatibility tests using human umbilical vein endothelial cells (HUVECs) show over 90% cell viability in direct and indirect contact. Stability tests in phosphate buffers at 37 °C confirm controlled degradation over 28 days. These results demonstrate that MCM is a promising, burn-free magnetic material for safe, localized heating, supporting its use in self-regulating, temperature-responsive biomedical systems.

We present a novel silicon-based organ-on-chip (OoC) device featuring integrated microelectrodes to assess barrier function in biological tissue co-cultures. The microfluidic device consists of two vertically-stacked microchannels separated by a submicron-thin, microporous silicon nitride membrane, enabling in vivo-like proximity for co-cultured tissues. The integrated four-probe electrode geometry on slanted microchannel sidewalls ensures unobstructed optical access to the membrane and consistent measurement repeatability. Experimental validation through electrical impedance spectroscopy supported the device's sensitivity to sodium chloride concentration. Fabricated through a scalable, wafer-scale batch process, the device additionally demonstrated biocompatibility and optical transparency, representing a significant advancement for in situ tissue barrier assessments.