Fig. 1

Characterization of cannulation materials. a 5/0 polypropylene suture with a mushroom-shaped tip. b Twisted 6/0 polypropylene suture with a loop tip. c iTrack™ with an inflated tip. d 5/0 polypropylene suture with a rough and sharp margin. e Twisted 6/0 polypropylene suture with a smooth tip. f The measurement of contact angle. A 5 µl droplet (red arrow) of distilled water from a very thin tube (yellow arrow) was used for contact angle measurement of polypropylene sutures (blue arrow). The angle (red angle) between the droplet (red arrow) and the surface of the suture (blue arrow) was 150°, which indicated the polypropylene was hydrophobic and stable in water. g Fourier transform infrared (FTIR) spectra of the polypropylene suture and iTrack™