A medical device and system capable of providing on-demand delivery of
biologically active material to a body lumen patient, and a method of
making such medical device. A first coating layer comprising a
biologically active material and optionally a polymeric material is
disposed on the surface of the medical device. A second coating layer
comprising magnetic particles and a polymeric material is disposed on the
first coating layer. The second coating layer, which is substantially
free of a biologically active material, protects the biologically active
material prior to delivery. The system includes the medical device and a
source of energy, such as an electromagnetic or mechanical vibrational
energy. When the patient is exposed to the energy source, the magnetic
particles move out of the second coating layer and create channels
therein through which the biologically active material can be released.