kinked silicon nanowires with nanofets encoded near the kink were synthesized using gold nanocluster catalyzed vapor - liquid - solid growth method as previously described .
probe fabrication was carried out on si substrates ( nova electronic materials , flower mound , tx ) with 600 nm sio2 coated with 100 nm ni , which serves as relief layer , and pre - baked ( 65 c for 2 min ) su8 2000.5 photoresist . kinked nanowires were deposited on desired region from ethanol dispersion using a micropipette , and then ebl was used to define nanowire end of the probe and pl used to pattern the remainder of the 4.5 mm long su8 probe body , which also serves as lower passivation of metal interconnects .
subsequently , a combination of ebl and pl steps were used to define the metal connections scaling from the kinked nanowire arms to the millimeter - scale end of the probe , where cr / pd / cr ( 1.5/120/60 nm ) was used for contacts to the nanowire , and cr / au ( 5/200 nm ) for the rest of the interconnections .
top su8 passivation / structural layers were defined using a 500 nm thick su8 2000.5 for the tip region covering the metal contacts , and a 50 m thick low - stress su8 layer ( glm 2060 , gersteltec ) for the majority of the probe body , which can increase the overall mechanical strength .
the kinked nanowire end of the probe was protected with 300 and 500 nm thick layers of lor 3a and s1805 ( microchem ) defined by pl .
after etching the ni layer ( 40% fecl3:39% hcl : h2o=1:1:20 ) , the floating probe structure was removed using tweezers and glued on the printed circuit board connector portion of the probe body that is mounted in the 3d manipulator
. the protective cap is removed immediately prior to measurements following uv exposure , and measurements were made in similar manner to previous chip - based device studies .
additional fabrication details , as well as cell culture and measurement protocols are described in the supplementary information .
 recording intracellular bioelectrical signals is central to understanding the fundamental behaviour of cells and cell - networks in , for example , neural and cardiac systems14 . 
 the standard tool for intracellular recording , the patch - clamp micropipette5 is widely applied , yet remains limited in terms of reducing the tip size , the ability to reuse the pipette5 , and ion exchange with the cytoplasm6 . 
 recent efforts have been directed towards developing new chip - based tools14,713 , including micro - to - nanoscale metal pillars79 , transistor - based kinked nanowire10,11 and nanotube devices12,13 . 
 these nanoscale tools are interesting with respect to chip - based multiplexing , but , to date , preclude targeted recording from specific cell regions and/or subcellular structures . here 
 we overcome this limitation in a general manner by fabricating free - standing probes where a kinked silicon nanowire with encoded field - effect transistor detector serves as the tip end . 
 these probes can be manipulated in three dimensions ( 3d ) within a standard microscope to target specific cells / cell regions , and record stable full - amplitude intracellular action potentials from different targeted cells without the need to clean or change the tip . 
 simultaneous measurements from the same cell made with free - standing nanowire and patch - clamp probes show that the same action potential amplitude and temporal properties are recorded without corrections to the raw nanowire signal . 
 in addition , we demonstrate real - time monitoring of changes in the action potential as different ion - channel blockers are applied to cells , and multiplexed recording from cells by independent manipulation of two free - standing nanowire probes . 
Methods Summary
Supplementary Material