The present invention provides a catheter for use in delivering and/or recovering materials to and/or from a tissue site in the body, the catheter comprising one or more macroporous regions adapted to selectively deliver molecules and/or recover cells from the tissue site, based on one or more physical-chemical-biological characteristics. The macroporous region can be provided in the form of a helical hollow wires, and can be adapted to both recover cells from the tissue site (e.g., bacterial or other cells present in interstitial fluid) and optionally to permit the infusion of medicament to the site, under corresponding conditions.
