A device for treatment of cells with particles is disclosed. The device includes a semi-permeable membrane positioned between two plates, the first plate defining a first flow chamber and comprising a port, a flow channel, a transverse port, and a transverse flow channel, the first flow chamber constructed and arranged to deliver fluid in a transverse direction along the first side of the semi-permeable membrane, the second plate defining a second flow chamber and comprising a port. A method for transducing cells is disclosed. The method includes introducing a fluid with cells and viral particles into a flow chamber adjacent a semi-permeable membrane such that the cells and the viral particles are substantially evenly distributed on the semi-permeable membrane. The method also includes introducing a recovery fluid to suspend the cells and the viral particles, and separating the cells from the viral particles. A method of activating cells is disclosed.