fig4

Figure 4. Miniature piezoresistive tactile sensors for catheters. (A) A tube-type tactile sensor consisting of an aqueous 50 mM KCl electrolyte as a conductor (left part) and its response sensing curve filtrated at 14 Hz (middle, right plot) and 5 Hz (bottom, right plot) compared to a commercial transducer (top, right plot) in an in vivo test^[58]. (B) A PI/SU-8 MEMS gauge pressure sensor (left part) and its response sensing signal curve of carotid arterial blood pressure and heart rate in a male mouse during inhalation of isoflurance (right plot)^[59]. (C) A PEDOT:PSS/PDMS MEMS force sensor for triaxial catheter contact force measurements (left part) and its output voltage with respect to time (top, right plot) and sensitivity (bottom, right plot)^[61]. MEMS: Microelectromechanical systems; PDMS: polydimethylsiloxane.