(a) Array of Au/ITO electrode patterned on Nuclepore® membrane and SEM image of electrode surface, (b) Schematic drawing of NO sensor components (not in scale, thick arrows indicate adhesive side); i) PE® insulating tape; ii) pAu/ITO electrode; iii) TeflonAF®-treated Celgard® membrane; iv) Nuclepore® membrane; v) Durapore® membrane filter; vi) HybriWell® chamber; vii) KCl/HCl internal solution; viii) Ag/AgCl wire; ix) a hole on (i-a) for GPM exposure to sample; x) a hole on (i-c) for contact to internal electrolyte; two electrodes, (ii) and (viii), are connected to potentiostat (P), (c) image of microfluidic NO detector; i) a lead connected to WE; ii) Ag wire from Ag/AgCl pseudo-RE; iii) Cu conducting tape for electrical contact between WE and a lead; iv) waste reservoir; v) sensing region where GPM of NO sensor exposed through a hole (x); vi) cell culture area on microchannel; vii) inlet for calibration solution; viii) inlet for culture media.