The objective of this project was to develop a new, computationally efficient, multiscale numerical model to simulate the directional and tumble motions of self-propelled chemotactic particles (live bacteria, or bacterial or chemical robots) in spatially and temporarily varying chemoattractant (e.g., nutrients) gradients in geometrically complex domains by accommodating cells scale adaptation dynamics and signal processing, and particle-scale fluid-particle hydrodynamics.