Biomedical Engineering Reference
In-Depth Information
Fig. 6.9
Program cell death (apoptosis)
Fig. 6.10
Interfacial potential change between solution and FSG for incubation time
Maybe both changes would be included in the electrical signal. Moreover, the FSG-
based FET without cells showed no potential shift after the addition of TRAIL,
although the effect of background noises such as temperature change, change in ion
concentration, and so on was observed in introducing it into the sample. Thus, it is
important to compare the signal of target sensor with the one of control sensor to
consider various background noises. Actually, the potential shift for the FSG-based
FET seemed to be larger than the signal for apoptosis measured by the IG-FET. This
may be because the surface area of FSG was larger than that of IG-FET, resulting
in the increase of number of adhered cells due to fibrous electrode. However, the
FSG-based FET needs to be improved in order to detect potassium ion specifically
and selectively by modifying chemically the fiber surface.
A biosensing technique to measure molecular charge distribution at cell mem-
brane was developed using a principle of semiconductor. In this research, a
cantilever of atomic force microscopy (AFM) was utilized in order to contact with
cell membrane and to move electrode at nanoscale, and a “gatelever” with platinum
tip was developed to detect charges at cell membrane using AFM. The gatelever as
electrode is extended from MOS-FET as one of the EG-FETs. Actually, negative
charges based on sialic acids and so on at cell membrane were detected using AFM
with gatelever-based FET. As a result, membrane protein with some charges at cell
membrane can be detected at nanoscale using the proposed system.
