Recombinant maxi-K Channels
on Transistor, A Prototype of Ionoelectronic Interfacing
Authors: B. Straub, E. Meyer, and P. Fromherz
Presenter: Todd Finkler
Disclaimer
You are about to enter the world of the unknown. The presenter’s background is in computer engineering, more specifically in networks. NOT in biological
engineering or biology or medical or in any field that would make this topic easy. However, this topic is interesting to the presenter, so the presenter is wading
forth into an area of unknown. If you chose to enter, you do so at your own risk. You may or may not get correct answers to your questions. You may or may
not walk away from this talk more confused than when you entered the room. There are some really smart people who are examining this field and the
presenter is not one of them. If you cannot read this, tough. If you can read this, I did not make this small enough. My bad. The presenter will not be held
responsible for any misguided teachings from this presentation. If you cannot agree to this, you know where the door is since you came through the door to get
here. This disclaimer is meant for entertainment purposes only, and is by no means intended to be serious. If, up to this point, you are still reading this and
you still think this is serious, you need to take a break from school – especially since it is still so early in the semester. And if you are still reading this, you have
a much longer attention span than I have. But that is good, because you will probably one of the few who actually pay attention to the whole presentation.
Thanks for paying attention this long. Thanks also to those who have supported my efforts to this point, including Weiwei for asking a barrage of questions
while I was developing these slides. Additionally, thanks to Koranan for her patience in getting this presentation at the last minute. And finally, thanks also to
Professor Newcomb for hopefully giving me an “A” in this class for the semester. Enough with this nonsense and lets move on with the presentation. The
following is a repeat of the above. You are about to enter the world of the unknown. The presenter’s background is in computer engineering, more specifically
in networks. NOT in biological engineering or biology or medical or in any field that would make this topic easy. However, this topic is interesting to the
presenter, so the presenter is wading forth into an area of unknown. If you chose to enter, you do so at your own risk. You may or may not get correct
answers to your questions. You may or may not walk away from this talk more confused than when you entered the room. There are some really smart people
who are examining this field and the presenter is not one of them. If you cannot read this, tough. If you can read this, I did not make this small enough. My
bad. The presenter will not be held responsible for any misguided teachings from this presentation. If you cannot agree to this, you know where the door is
since you came through the door to get here. This disclaimer is meant for entertainment purposes only, and is by no means intended to be serious. If, up to
this point, you are still reading this and you still think this is serious, you need to take a break from school – especially since it is still so early in the semester.
And if you are still reading this, you have a much longer attention span than I have. But that is good, because you will probably one of the few who actually pay
attention to the whole presentation. Thanks for paying attention this long. Thanks also to those who have supported my efforts to this point, including Weiwei
for asking a barrage of questions while I was developing these slides. Additionally, thanks to Koranan for her patience in getting this presentation at the last
minute. And finally, thanks also to Professor Newcomb for hopefully giving me an “A” in this class for the semester. Enough with this nonsense and lets move
on with the presentation. The following is a repeat of the above. You are about to enter the world of the unknown. The presenter’s background is in computer
engineering, more specifically in networks. NOT in biological engineering or biology or medical or in any field that would make this topic easy. However, this
topic is interesting to the presenter, so the presenter is wading forth into an area of unknown. If you chose to enter, you do so at your own risk. You may or
may not get correct answers to your questions. You may or may not walk away from this talk more confused than when you entered the room. There are
some really smart people who are examining this field and the presenter is not one of them. If you cannot read this, tough. If you can read this, I did not make
this small enough. My bad. The presenter will not be held responsible for any misguided teachings from this presentation. If you cannot agree to this, you
know where the door is since you came through the door to get here. This disclaimer is meant for entertainment purposes only, and is by no means intended
to be serious. If, up to this point, you are still reading this and you still think this is serious, you need to take a break from school – especially since it is still so
early in the semester. And if you are still reading this, you have a much longer attention span than I have. But that is good, because you will probably one of
the few who actually pay attention to the whole presentation. Thanks for paying attention this long. Thanks also to those who have supported my efforts to this
point, including Weiwei for asking a barrage of questions while I was developing these slides. Additionally, thanks to Koranan for her patience in getting this
presentation at the last minute. And finally, thanks also to Professor Newcomb for hopefully giving me an “A” in this class for the semester. Enough with this
nonsense and lets move on with the presentation. The following is a repeat of the above.
Joining Computer and Brain
Why Important?
 The challenge – different charge carriers

◦ Computer – electrons in solid ion lattice
◦ Brain – electrons in polar fluid
A Little Biology…
How Cells Transmit Signals…
How Cells Transmit Signals
(cont.)
Passing the Signal
What Cell to Use?

HEK293 – What?
◦ Human Embryonic Kidney cell line with
sheared adenovirus 5 DNA

HEK293 – Why?
◦ Conductance properties
◦ Well-defined ion channel
What Interface?

human slowpoke (hSlo)
maxi-KCa channel
◦ Perfectly controlled by patchclamp
◦ Displays high single-channel
conductance yielding large
membrane current.
◦ Is target for estradiol –
potentially useful for biosensor
Neuron on Transistor
Applying Voltage to the Cell
58 mV
53 mV
45 mV
40 mV
30 mV
-23 mV
-68 mV
Average Transistor Signal
VJ/IM = 73 mV/nA
Relations
VJ = RJAJMgJM(VM – V0) where:
VJ is the extracellular voltage in the gap
RJ is the gap’s ohmic resistance
AJM is the area of the attached membrane
gJM is the average specific K+ conductance
IM = AMgM(VM – V0)
VJ / IM is constant experiementally, so…
gJM / gM must be constant for all VM
And…
Boltzmann’s equation can describe their voltage-dependent
gating
g/gbar = 1/(1 + e[z(V0.5 – VM)/Vth] ) where…
z
is the gating charge
V0.5 is the half-maximum activation at a max specific gbar
Conductance Measurements
Questions