A Revolution in Electronic & Medical Sector…….

MICRO ELECTRONIC PILL

Presented by :pushpa n

GUIDE: HOD:MR.ISHWAR CHANDRA MR.PROF. NAGENDRA

Microelectronic pill is a swallowable pill which records parameters like temperature, pH, Conductivity, & Dissolved Oxygen in real time.[1]

Professor Jon Cooper and Dr Erik Johanessen from Glasgow University, U.K led to the development of a microelectronic pill.[1]

When Microelectronic pill is swallowed, it will travel through the Gastro Intestinal Tract & simultaneously perform multiparameter physiological analysis.[2]

After completing its mission it will come out of the body by normal bowel movement.[2]

The pill is 16mm in diameter & 55mm long weighing around 5 gram[2].

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

A “Microelectronic pill” is a basically a multichannel sensor used for remote biomedical measurements using microtechnology. [1]

This has been developed for the internal study and detection of diseases and abnormalities in the gastrointestinal (GI) tract where restricted access prevents the use of traditional endoscope. [1]

The measurement parameters for detection include real – time remote recording of temperature, pH, conductivity and dissolved oxygen in the GI tract.[1]

What is MICROELECTRONIC PILL?

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

Endoscopy has restricted access to gastrointestinal (GI) tract.[1]

First radio telemetry capsules utilized simple circuits for in vivo telemetric studies of the gastro-intestinal tract. [1]

These units could only transmit from a single sensor channel, and were difficult to assemble due to the use of discrete components. [1]]

The first attempts of conducting real-time physiological measurements suffered from poor reliability, low sensitivity, and short lifetimes of the devices.[1]

Microelectronic pill overcomes these disadvantages. It incorporates a four-channel micro sensor array for real-time determination of temperature, pH, conductivity and oxygen.[1]

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

Microelectronic pill :1-access channel2-4sensors(mounted on two silicon chips (chip1&chip2)3-capsule4-rubber ring5-control chip6-PCB chip carrier7-radio transmitter8- silver oxide batteries 9- reverse side of the PCB 10- crystal oscillator

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

The sensors were fabricated on two silicon chips located at the front end of the capsule.

a) Chip 1 comprises the silicon diode temperature sensor, the pH ISFET sensor and a two electrode conductivity sensor.

b) Chip 2 comprises the oxygen sensor.

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

The ISFET measures pH.

The advanced meters have real-time clocks for time/date stamping, calibration alerts and high/low pH alarms.

Three new series of ISFET probes include the Red-Line general purpose series , Hot-Line series , Stream-Line series.

It can reveal pathological conditions associated with abnormal pH levels.

ISFET used to measure ion concentrations in solutions

ION-SELECTIVEION-SELECTIVEFIELD EFFECT TRANSISTORFIELD EFFECT TRANSISTOR

(ISFET)(ISFET)

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

The silicon diode temperature sensor is an extremely common form of temperature sensor used in electronic equipment.

The principle of the sensor is that the forward voltage of a silicon diode is temperature-dependent.

Its main advantage is that it can be included in a silicon integrated circuit at very low cost.

Silicon Diode Temperature SensorSilicon Diode Temperature Sensor

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

The pair of direct contact Gold electrodes measures conductivity, by measuring the contents of water & salt absorption, and fluids in the GI tract.

When the fluids flow into the pill, the voltage difference between the electrodes results in the flow of current due to ions present in fluids, which determines the conductivity.

Since the gold has best conductivity among all the elements, Therefore it gives true value of conductivity as measured.

TWO ELECTRODE CONDUCTIVITY TWO ELECTRODE CONDUCTIVITY SENSOR(GOLD ELECTRODE)SENSOR(GOLD ELECTRODE)

3- electrode electrochemical cell:

The 3-electrode electrochemical cell is used to detect the level of dissolved oxygen in solution.

The oxygen sensor measures the oxygen gradient from the proximal to the distal GI tract.

Oxygen Sensors are based on the electrocatalytic reduction of oxygen at the electrode surface.

It investigates of growth bacterial infection, cellular injury & Gastric ulceration.

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

The ASIC (Application Specific Integrated Circuit) is the control unit that connects together other components of the microsystem.

It contains an analogue signal –conditioning module operating the sensors, 10-bit analogue to digital (ADC) & digital to analogue (DAC) converters, & digital data processing module.

The temperature circuitry bias the diode at constant current so that change in temperature reflects a corresponding change in in diode voltage.

The pH ISFET sensor is biased as a simple source at constant current with the source voltage changing with threshold voltage & pH.

1. S. Mackay and B. Jacobson, " Endoradiosonde ,& quot; Nature, vol. 179, pp. 1239-1240, 1957. 2. H. S. Wolff, & quot; The radio pill ," New Scientist, vol 12, pp. 419-421, 1961.

The conductivity circuit operates at D.C. It measures the resistance across the electrode pair as an inverse function of solution conductivity.

An incorporated potentiostat circuit operates the O2 sensor with a 10 bit DAC controlling the working electrode potential w.r.t the reference.

Analogue signals are sequenced through a multiplexer before being digitized by ADC.

ASIC & sensors consume 5.3mW power corresponding to 1.7mA of current.

(a), the associated explanatory diagram (b), and a schematic of the architecture (c) illustrating the interface to external components. MUX (four-channel multiplexer), ADC, DAC, and OSC (32-kHz oscillator).

Size of transmitter = 8×5×3 mm

Modulation Scheme = Frequency Shift Keying (FSK)

Data Transfer Rate = 1 kbps

Frequency = 40.01 MHz

Bandwidth of the signal generated 10 KHz

It consumes 6.8 mW power at 2.2 mA of current.

2 SR44 Ag2O batteries are used.

Operating Time > 40 hours.

Power Consumption = 12.1 mW

Corresponding current consumption = 3.9mA

Supply Voltage = 3.1 V

RANGE :

Temperature from 0 to 70°C

pH from 1 to 13

Dissolved Oxygen up to 8.2 mg per liter

Conductivity above 0.05 m-mho/cm.

Full scale dynamic Range analogue signal = 2.8 V

ACCURACY :

pH channel is around 0.2 unit above the real value

Oxygen Sensor is ±0.4 mg/L.

Temperature & Conductivity is within ±1%.

It is being beneficially used for disease detection & abnormalities in human body. There fore it is also called as MAGIC PILL FOR HEALTH CARE

Adaptable for use in corrosive & quiescent environment

It can be used in industries in evaluation of water quality, Pollution Detection, fermentation process control & inspection of pipelines.

Micro Electronic Pill utilizes a PROGRAMMABLE STANDBY MODE, So Power consumption is very less.

It has very small size, hence it is very easy for practical usage

High sensitivity, Good reliability & Life times.

Very long life of the cells(40 hours), Less Power, Current & Voltage requirement (12.1 mW, 3.9 mA, 3.1 V)

Less transmission length & hence has zero noise interference.

It cannot perform ultrasound & impedance tomography.

Cannot detect radiation abnormalities

Cannot perform radiation treatment associated with cancer & chronic inflammation.

Micro Electronic Pills are expensive & are not available in many countries.

Still its size is not digestible to small babies

Further research are being carried out to remove its draw backs.

Designed to perform real-time measurements of the GI tract, providing the first wireless transmitted multichannel recordings of analytical parameters.

Microelectronic pill in future will improve the detection of tissue abnormalities and radiation treatment associated with cancer and chronic inflammation.

The overall concept will be to produce an array of sensor devices distributed throughout the body or the environment, capable of transmitting high-quality information in real-time.

WEB REFERENCE:-

1. http://ubimon.doc.ic.ac.uk/bsn/public/Jon_Cooper.pdf

2. http://citeseerx.ist.psu.edu

3. http://www.forumsains.com

BOOK REFERENCE:-

1. S. Mackay and B. Jacobson, "Endoradiosonde," Nature, vol. 179, pp. 1239-1240, 1957.

2. H. S. Wolff, "The radio pill," New Scientist, vol 12, pp. 419-421, 1961.