Plasma systems for depositing biomolecules, pharmaceutical agents, and other therapeutic active agents onto surfaces are described. The systems may include a plasma device having one or more electrodes, a gas supply inlet, a plasma outlet exposed to ambient pressure, and an ignition system operatively connected to the electrodes for providing a non-thermal equilibrium plasma within the plasma chamber. A particulate delivery system may be used to introduce the active agent(s) as a dry powder into or downstream of the plasma, and to deposit the plasma-treated active agent(s) to produce a coating on a surface. The coating may retain the activity of the active agent(s).