Methods are described of delivering biological material, which methods include the steps of providing a liquid formulation containing the biological material, supplying the liquid formulation to an outlet and subjecting liquid issuing from the outlet to an electrical field thereby causing electrohydrodynamic processing of the liquid without denaturing the biological material. In one example, the liquid formulation is provided by removing salts from a formulation containing biological material that does not denature in alcohol and then adding an alcohol to the formulation before supplying the liquid formulation to the outlet. An acid may be added to the liquid formulation before supplying the liquid formulation to the outlet.