The present disclosure provides apparatuses and systems for delivering a measureable absorbed-dose of a gaseous activating agent to a fluid including a biological liquid and/or cells. The apparatuses or systems include a gas-fluid contact device configured to controllably rotate or oscillate a control member having an interior surface in contact with the fluid and a control system configured to control rotation or oscillation of the contact member by the gas-fluid contact device. In some embodiments, the control system is further configured to control absorption of the gaseous activating agent by the fluid. The present disclosure also provides methods of treating a fluid including a biological liquid or cells with a gaseous activating agent to controllably activate the fluid.
