A scaffold is a physical structure. Manufactured tissue scaffolds can be produced to replace damaged parts, or sometimes to act as a centre for natural; tissue to attach, promoting regeneration of damaged tissue or structure. For example it might be a 3D-printed structure in the right shape for a missing are of bone, the material chosen so that the body forms attachments and integrates the structure into itself.

I think 'drung delivery' is a misspelling for "drug delivery" A 'scaffold' in this context is a delivery method to insert genes/cells/drugs into the human body. A tissue scaffold would deliver or inject tissue into the body, I would assume.