An injection catheter system that includes (a) an actuator; (b) an outer needle comprising a sharp tip and a tubular body defining a lumen, and extending distally from the actuator; and (c) an inner needle at least partially disposed within the lumen and extending distally from the actuator, the inner needle having a distal tip configured such that at least a portion of the distal tip has a surface contour with an interstitial cavity adapted to receive a therapeutic gel. The system is configured such that (a) in a first position, the distal tip is fully disposed within the lumen to temporarily retain the therapeutic gel in the interstitial cavity and (b) in a second position, the outer needle is retracted proximally, exposing the interstitial cavity to deliver the therapeutic gel to a target area in a body.