‘Nano scale [is] magic scale’: on EPR, unicorns, and enchantment in nanomedicine

Nanotechnology is a scientific field where STS scholars have observed the influence of magical thinking. Here we contribute to that literature by describing a phenomenon in the field of drug delivery called the EPR (Enhanced Permeability and Retention) Effect. When the ‘nano’ boom of the 2000s brought intense interest from outside pharmacology, EPR spawned so many efforts and enterprises in nano-based drug delivery that it became the leading basis for nanomedicine’s promise. Following the 2016 failure of a prominent nano-biotech firm exploiting EPR, the collapse of the field offers insights into the role such theories or narratives played in the formation of nanomedicine and, more broadly, how contemporary technoscience may incorporate elements of enchantment—particularly where exposed to financialization.