Rational Design of Self-Propelling Particles for Unified Cargo Loading and Transportation.

Recent studies on electrically powered active particles that can both self-propel and manipulate cargo load and release, have focused on both spherically shaped Janus particles (JP) and on a parallel electrically conducting plates setup. Yet, spherically shaped JPs set a geometrical limitation on the ability to smartly design multiple dielectrophoretic traps on a single active particle. Herein, these active carriers are extended to accommodate any desired shape and selective metallic coating, using a standard photolithography method. The resulting designed positive and negative dielectrophoretic traps of controlled size, location, and intensity, performed as sophisticated active carriers with a high level of control over their mobility and cargo loading. In addition to cargo loading, the engineered particles exhibit interesting motion in an electrically insulating substrate setup, with in-plane electric field, and, in particular, a tilt angle, and even flipping, that strongly depended on the field frequency and amplitude, hence, exhibiting a much more diverse and rich behavior than spherical JP. The engineered self-propelling carriers are expected to open up new possibilities for unified, label-free and selective cargo loading, transport, and delivery of complex multi-particles.