Phoresis

Phoresis is a term describing the transport of a particle or organism by another body or a field, with movement driven by gradients or external forces rather than by active propulsion or chemical alteration of the carrier. The word derives from Greek and broadly means “bearing” or “carrying.”

In physical and chemical contexts, phoresis refers to the motion of dispersed particles through a medium under the influence of a gradient or force. This category encompasses several subtypes, including electrophoresis (movement in an electric field), dielectrophoresis (movement in a non-uniform electric field due to polarization), diffusiophoresis (movement in response to solute concentration gradients), thermophoresis (movement along a temperature gradient), and photophoresis (movement driven by light). Phoresis differs from simple diffusion because it involves directed forces or gradients that advect particles rather than relying on random thermal motion alone. In some frameworks, dielectrophoresis is treated as a specialized phoretic process.

In biology, phoresis describes a non-feeding association in which one organism (the phoront) is transported by another (the host) for dispersal. This relationship is not typically mutualistic and does not involve nutrient exchange or harm to the host in the classic sense. Common examples include mites or nematodes hitchhiking on insects or other animals to reach new habitats.

Applications of phoretic phenomena appear in laboratory techniques and devices, such as microfluidic sorting, particle manipulation, and the study of dispersion mechanisms, as well as in ecological and evolutionary contexts where phoretic dispersal shapes population dynamics. The concept thus spans physics, chemistry, and biology as a description of transport driven by forces or gradients rather than by active motion or metabolism.