Fig. 1.2 Intracellular electrical recording by nanowire nanoFET device.aA 3D, free-standing
kinked nanowire FET probe bent up by stress release of the metal interconnects. The yellow arrow
and pink star mark the nanoscale FET and SU-8, respectively. Scale bars, 5μm.bTransition from
extracellular (I) to intracellular recordings during (II) cellular entrance recorded by a kinked
nanowire FET probe from beating cardiomyocytes. Green and pink stars denote the peak positions
of intracellular and extracellular signal components, respectively; (III) Steady-state intracellular
recording.cZoom-in signals of an intracellular action potential peak. Blue and orange stars
designate features that are possibly associated with inward sodium and outward potassium currents,
respectively. The letters‘a’to‘e’denotefive characteristic phases of a cardiac intracellular
potential, as defined in text. The red-dashed line is the baseline corresponding to intracellular resting
state Reprinted with permission from Ref. [ 18 ]. Copyright 2010 American Association for the
Advancement of Science..dSEM image of a BIT-FET device (S–D1) and control device (S–D2).
e(I), Representative trace (conductance vs. time) reflecting the transition from extracellular to
intracellular recording. (II) Magnified view of the trace inside the black dashed rectangle in (I). (III)
Magnified view of the trace inside the blue dashed rectangle in (II). The stars in (II) and (III) mark
the position of extracellular spikes. (IV) Magnified view of the peak inside the red dashed rectangle
in (I) Reprinted with permission from Ref. [ 93 ]. Copyright 2014 Nature Publishing Group.
with a phospholipid bilayer, on a silicon nanowire to bring the cytosol into contact
with the FET region on the bottom when the tube was inserted into cells (Fig.1.2d,
e). Multiplexed intracellular recordings from a single cell or cellular network have
been demonstrated with this technique. Based on these two concepts, several dif-
ferent intracellular electrophysiological recording techniques have been further
developed [ 94 – 96 ].
In addition to electrophysiological recording, nanowires and nanowire-related
structures have been used for delivery of biomolecular materials into cells that are
inaccessible by traditional methods [ 97 – 99 ] to interrogate genomic behavior of cells.
6 1 Introduction