A method of attaching a molecule-of-interest to a microtube, by co-electrospinning two polymeric solutions through co-axial capillaries, wherein a first polymeric solution of the two polymeric solutions is for forming a shell of the microtube and a second polymeric solution of the two polymeric solutions is for forming a coat over an internal surface of the shell, the first polymeric solution is selected solidifying faster than the second polymeric solution and a solvent of the second polymeric solution is selected incapable of dissolving the first polymeric solution and the second polymeric solution comprises the molecule-of-interest, thereby attaching the molecule-of-interest to the microtube. An electrospun microtube comprising an electrospun shell, an electrospun coat over an internal surface of the shell and a molecule-of-interest attached to the microtube.
