Time-Controlled Nanoscale Delivery System

Molecular communication (MC), a bio-inspired technology, is emerging as an alternative way of communication by overcoming the limitations of conventional electromagnetic waves. As the demand for practical implementation of MC grows, physical components of MC (<i>e.g.</i>, transmitter and receiver) have been fabricated through the integration of nano-/micro-technology. However, challenges such as slow speed of information molecule (IM) transmission, dispersion of IMs into the surrounding medium, and interference between sequentially transmitted IMs persist in employing the transmitters. Furthermore, sequential delivery of multiple IMs with an adjustment of their time intervals to enhance the communication efficiency remains as a significant challenge. Herein, we report a time-controlled delivery system that utilizes nanomotors as transmitters achieving precise multi-cargo delivery with desired time intervals. Nanomotors consisted of multi-metal nanorod (<i>i.e.</i>, nickel head, gold bridge, silver flexible filament, and gold tail) are encapsulated with poly (N-isopropylacrylamide) (pNIPAm) based hydrogel, and nanomotors with various dimensions transport multi-cargo as IMs (<i>e.g.</i>, Indigo carmine and Carminic acid) at different speeds under the same magnetic field. Consequently, nanomotors release IMs on-demand at desired locations upon near-infrared (NIR) irradiation, leading to IM delivery with high spatiotemporal density. Continuous linear sweep voltammetry (LSV) confirmed the sequential delivery of multiple IMs with time intervals of several minutes, indicating that nanomotors can transport IMs at higher transmission rate compared to diffusion-based methods. Furthermore, IM delivery using nanomotors exhibited higher signal intensity and reduced intersymbol interference (ISI), which enables a continuous signal transmission with a lower error rate in communication. We believe our time-controlled multi-cargo delivery via nanomotors can serve as transmitters paving a way to realize practical MC systems, such as disease detection and monitoring. This will allow us to understand communications in biological/biomimetic systems or unexplored environments.