Self-Adaptive Magnetic Photonic Nanochain Cilia Arrays

The development of multifunctional artificial cilia may inspire a new generation of intelligent biomimetic microdevices and microfluidic systems, but remains a great challenge. Here, self-adaptive magnetic photonic nanochain cilia arrays (SMPNCAs) capable of achieving real-time and in situ visual microenvironment detection and self-adaptive fluid pumping are shown. By combining magnetic assembly and UV-assisted hydrogen bond-guided template polymerization in printing, SMPNCAs consisting of individual 1D periodic structure of magnetic nanoparticles encapsulated in pH-responsive hydrogel shells, as an example, are demonstrated to be printed on a glass substrate with defined patterns in one step. The as-printed SMPNCAs exhibit real-time adjustable interparticle distance (lattice constant) and total length in response to the reversible volume change of the hydrogel shell with the pH value of the pumped fluids. Consequently, they can sense the surrounding pH variation in real time by in situ displaying different diffracted color, and pump directional flows with self-adaptive flow velocity under a rotating magnetic field. Benefiting from the integration of the facile, robust printing fabrication, structure-color-based fast sensing, and self-adaptive fluid pumping, the SMPNCAs that are developed here promise a significant advancement in biomimicry and microfluidic systems.