Turning Up the Heat: Wireless Induction Heating for Multitemperature Microscale Reactions

Temperature control is central to high-throughput experimentation (HTE), yet reliable heating in disposable plastic multiwell plates remains challenging. Global heating is inefficient in low-thermal-conductivity plastics, can produce well-to-well temperature gradients, and may degrade plasticware or contaminate reactions under excessive or uneven heating. Temperature screening across multiple set points is also highly desirable but difficult to implement at plate scale with conventional approaches, because different temperatures typically require separate plates or hardware, increasing effort and introducing batch effects. Here, we introduce a wireless induction-heating platform that places small metal balls in each well to generate heat directly in the reaction mixture. By heating within each well of a disposable plastic plate, metal ball-mediated induction enables stable in-well temperatures and programs multiple discrete temperature zones within a single multiwell plate by varying only the metal ball count under a single global induction setting. Fiber-optic probe measurements of in-well temperature show a rapid approach to stable temperature plateaus with minimal thermal crosstalk under the conditions employed, and we provide calibration relationships linking induction setting and metal ball count to in-well temperature. The same metal balls also support tumble-stir mixing and can be reagent-coated for ChemBead-style solid delivery. We demonstrate the platform through temperature-resolved microscale cross-coupling screens and a 384-member library synthesis in disposable 384-well plates.