CMOS MICROELECTRODE ARRAY FOR MONITORING ELECTROGENIC CELLS

8/7/2019 CMOS MICROELECTRODE ARRAY FOR MONITORING ELECTROGENIC CELLS

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CMOS MICROELECTRODE ARRAY

FOR MONITORING ELECTROGENIC

CELLSPRESENTED BY,RENIT RAGHAVAN

S7 EC

ROLL NO:44

INTERNAL GUIDE:REMYA RAMESH



OVERVIEW

´ Introduction´ History

´ Electrogenic cells

´ Why CMOS?

´ System architecture

´ Application

´ Advantages

´

Future enhancement´ Conclusion

´ Reference



INTRODUCTION

´ Its a new biochip consisting of an array of

microelectrodes with fully integrated analog

and digital circuitry

´ CMOS MEAs are used for the stimulation and

recording of activity from electrogenic cells

´ Its generally a metallic electrode with similar

diameter as the cell



HISTORY

´Recording electrical oscillations in the brainbegan in 1875

´ Traditional methods include patch clamp and

voltage-sensitive dyes

´MEAs was discovered in the early 1970s bywise and thomas

´ In the year 2001 single chip solutions withfully-integrated CMOS multiplexing andbuffering circuitry was presented



ELECTROGENIC CELLS

´ Cells that exhibit the ability to become

electrically active are called electrogenic cells.

´

Cardiomyocyte (heart cells) or neurons (braincells) are examples of electrogenic cells

´ They rely on electric signals to communicate

with each other

´ They have the ability to produce voltage

changes called action potentials



ELECTROGENIC CELLS

´ Biochemical processes in vertebrates arebased on the activity of these cells

´ Diseases based on malfunction of

electrogenic cells are among the most serioushealth problems

´ The cell activity can be measured

extracellularly by using a microelectrode



ELECTROGENIC CELLSMAMMALIAN NEURONS



ELECTROGENIC CELLS

cardiomyocytes(heart cells) or neurons(brain cells)



WHY CMOS?

´ Complementary metal-oxide-semiconductor(CMOS) is a technology for constructing

integrated circuits

´ High noise immunity and low static powerconsumption

´ It offers some decisive advantages, in

particular multiplexers and on-chip electronics



CMOS CHIP



MEA(MICROELECTRODE ARRAY)

´ In a MEA, numerous electrodes are arranged

in an array on a planar substrate

´

Neural signals are delivered or obtainedthrough MEA

´ Neurons and muscle cells create ion currents

through their membranes when excited

´ When recording, the electrodes on an MEA

transduce the change in voltage



VITRO MEA



CMOS MEA¶S

´MEAs fabricated in CMOS are called CMOS

MEAs

´

The use of CMOS electronics overcomes thedrawbacks of traditional MEAs

´ CMOS electronics offer on-chip multiplexers

´ It has MOS switches, which allow to use the

electrode for both, recording and stimulation



S YSTEM ARCHITECTURE

´ The chip size is 6.5mm by 6.5mm

´ It consists of 128 electrodes in an 8x16 array

´ The pitch of the pixel unit is 250 micro meter

´ A digital control unit is integrated on the chip

´ It consists of 16 ADC and a DAC

´ An on-chip temperature sensor monitors the

chip operating temperature



MICROGRAPH OF CMOS MEA





SYSTEM ARCHITECTURE

´ Action potential in an electrogenic cell causes

ion flow across the cell membrane

´

This induce charges on the metal electrode´ Offsets of the electrode potential of up to 1 V

and drifts of up to 100 mV within a few

seconds have been measured

´ A high-pass filter has been used as the first

read-out stage



SYSTEM ARCHITECTURE

´ The signals then pass a low-pass filter with a

corner frequency of about 5 kHz to prevent

high-frequency aliasing

´ Finally, a buffer with a larger bandwidth has

been realized to further amplify the signal and

to allow for multiplexing

´ To achieve good signal-to-noise ratio, an 8-bit

A/D converters has been used



RESULTS

Neural spike recording using cmos-mea



APPLICATION

´MEA finds a multitude of applications in both

applied and pure science

´ It is used to study about brain

´ Used for the detection of chemical and

biological toxins

´ To study about health problems



FUTURE ENH ANCEMENT

´ An MEA with more number of electrodes

´ Integration of more sensors

´

Use of stimulation buffer



CONCLUSION

´ CMOS MEA is a monolithic extracellular

recoding system

´ A new technology for the neuroscientist

´ Viable approach to recover skeletal muscle

function and to restore visual perception



ADVANTAGES

´ CMOS MEA include multiplexers and on chip

electronics

´ Improved signal to noise ratio

´ Low power consumption

´ On-chip A/D and D/A conversion



REFERENCE

´ Bates, J.B., Chu, Y.T., 1992. Electrode²

electrolyte interface impedance:experiments

and model. Ann. Biomed. Eng. 20 (3), 349²

362.´Maher, M.P., Pine, J., Wright, J., Yu Chong, T.,

1999. The neurochip: a new multielectrode

device for stimulating and recording fromcultured neurons





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CMOS MICROELECTRODE ARRAY FOR MONITORING ELECTROGENIC CELLS