There is presently provided a suspension of immiscible particles in a solution, wherein the particles comprise an agglomeration of a bioactive agent, for example an anti-cancer agent; and a plurality of conjugates of a hyaluronic acid and a flavonoid, for example a catechin-based flavonoid, wherein the particles are on average from about 15 nm to about 300 nm in diameter and wherein the bioactive agent is releasably retained in the particles by the flavonoid. The suspension is useful for delivery of the bioactive agent to cells, including cancer cells. There are also provided a therapeutic formulation comprising the suspension, as well as methods for using the suspension and therapeutic formulation, including for delivery of a bioactive agent to a cell and for treating a disease, including cancer.