Dissipation and swimming efficiency of encapsulated active particles

We derive exact analytical expressions for the power dissipation (PD) and swimming efficiency (SE) of an active particle enclosed in a droplet in a Brinkman medium. Our analysis reveals that the SE of an encapsulated particle strongly depends on droplet size and environmental factors, including the viscosity ratio and medium porosity. For the active particles considered, the locomotion mode (slip- versus torque-driven) does not affect SE. For biomedical applications such as drug delivery, Lighthill's SE (ratio of towed rigid particle PD to swimming PD) determines which active particles (self-propelled or field-driven) would be more energetically favorable.