Cooperative signaling and directed migration of bio-nanomachines in mobile molecular communication

In this paper, we propose a molecular communication system where bio-nanomachines cooperate in signaling and move directionally toward a target area in the environment. In the proposed system, bio-nanomachines, upon entering a target area, release signal molecules in pulses, and nearby bio-nanomachines respond to the signal molecules by further releasing signal molecules in pulses. When bio-nanomachines are distributed around a target area, signal molecules propagate over long distance as a traveling wave in the environment, where the direction of a traveling wave encodes the location information about a target area. Bio-nanomachines outside a target area implement the relay-and-stop mechanism; they relay signal molecules and stop for a short period of time in order to bias their motion toward a target area based on the direction of a traveling wave. Numerical results show that the proposed system outperforms existing systems in terms of the number of bio-nanomachines that move closer to target areas. Application of the proposed system is anticipated to improve the performance of cooperative drug delivery using bio-nanomachines.