Transistor arrays for the direct interfacing with electrogenic cells

In this work, a floating gate field effect transistor (FET) for the coupling of electrogenic cells was presented. The design decoupled the transistor gate from the sensing area and arranged them one upon the other (sandwich design). Both parts were tuned individually: the transistors were optimised towards high transconductance and low noise, and the sensing area was adapted to the size of the investigated cells. Besides saving space, the sandwich design implied a protection of the vulnerable, thin gate oxide from the electrolyte solution, resulting in long-lasting and reusable devices. The first part of the fabrication process is compatible with a standard complementary metal oxide semiconductor (CMOS) process, including p-channel FETs, n-channel FETs and capacitors. The second part of the process, including the interconnect layer and the passivation layer protecting the devices from an electrolyte solution, was developed during these studies. To be compatible to the PECVD tool depositing the passivation layer, the interconnect layer was made out of polysilicon. To reduce the specific resistance of the feed lines, they were silicided with titanium. The passivation consisted of a layer stack of silicon dioxide, silicon nitride and silicon dioxide. The sensing areas were etched free and thermally oxidised to form a thin sensing dielectric and to enable a floating gate structure.The different chips of the fabricated wafers contained single electronic components, logical circuits, individually contacted sensor arrays, addressable sensor arrays, or arrays for recording and stimulation, simultaneously. The transistor's capability for extracellular coupling was successfully tested with different cellular systems. However, in comparison to open-gate FETs, the floating gate involved an additional drift that interfered with long-term measurements. For measurements in the range of minutes, the quasi-linear drift could easily be subtracted from the signal. The sandwich design of the transistors is space-saving and decouples the sensing area from the transistor gate. This makes the devices long-lasting and reusable. The additional electrical connection of the floating gate by means of a capacitor enables a capacitive stimulation of coupled cells. Thus, the presented floating gate FETs are a promising concept for the bidirectional extracellular coupling of electrogenic cells.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2006

Author dc:creator

• Meyburg, Sven

Contributors dc:contributor

• Offenhäusser, Andreas

• info:eu-repo/classification/ddc/570
• Biowissenschaften, Biologie
• Biosensor
• Feldeffekttransistor
• CMOS
• Adressierung
• Extrazelluläre Aufzeichnung
• Herzmuskelzelle
• Floating Gate
• HEK-Zelle
• field effect transistor
• FET
• addressing
• cell coupling
• cardiac myocyte
• HEK-cell

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122333%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:60631