Provided herein are methods of activating immune cells. The method includes providing a population of immune cells and contacting the population of immune cells with a first agent and a second agent. The first agent includes an immune cell activator attached to a first binder moiety, and the second agent includes at least one capture oligomer. The at least one capture oligomer is capable of associating with the first binder moiety. Also provided are kits for activating immune cells.