The invention provides porous three dimensional scaffold structures that may be used to deliver a bioactive agent, such as cells, into a location within the body. In one example form, the porous three dimensional structure may be a stent. In another example form, the porous three dimensional structure may be a microscale or nanoscale device for the delivery of the bioactive agent. The scaffold may include a substrate and one or more nests connected to the substrate. The nest(s) extend away from the substrate to define an enclosed volume on the substrate within each nest. The nests have openings that extend from an outer surface of the nest to the enclosed volume within each nest. The scaffold includes a bioactive agent disposed within the enclosed volume of at least one nest on the substrate. The bioactive agent is delivered to the patient when the scaffold is located within the patient.