In one aspect of the present disclosure, an apparatus for delivering a powdered agent into a subject's body may include a powder chamber housing the powdered agent. The apparatus also may include a chassis in fluid connection with the powder chamber. The chassis may include a first passage for receiving a pressurized gas, a second passage for receiving the powdered agent from the powder chamber, and a junction in fluid communication with the first passage and the second passage. At least a first portion of the pressurized gas is introduced into the powdered agent at the junction to fluidize the powdered agent.