Usage of Microelectronic Pills In Today’s World

 What are exactly microelectronic pills?

Our body has a very delicate system. Most of the time, it is difficult to diagnose a disease which leads to the treatment being delivered too late. Late treatment can eventually lead to the death of a person.

The solution to this problem in the health care industry was thought of by Professor John Cooper and Eric Johnson of Glasgow University in 1972. Finally came the idea is known as the electronic pill.

An electronic pill is a medical monitoring system. It measures parameters such as temperature, Ph levels, airflow and dissolved oxygen. They can take pictures and send them back to the system. They can be easily swallowed. The preferred sizes of these tablets are 16mm wide, 55 mm long, and weigh 5 grams. They are also required to be covered with a polyether-terketone (PEEK) resistant coating.

Fig 1: Microelectronic pill with the dimension of its components

When it moves through the gastro-intestinal tract it will start detecting abnormalities and diseases. Then it delivers all the information to an external system. All this information sharing happens in real-time. The external system in this case is a full network synced computer which is a distance of one meter or more.

What is the structure of a microelectronic pill?

The major parts of electronic pills are the four sensors, an ASIC chip, a radio transmitter and a power source.

Fig 2: Structure of Components inside a microelectronic pill

Radio-Transmitter: It is something that will transfer data from the base station to the end which will receive the signal. The size of this is around 8X4X3 mm. The data transfer rate is 1 Kbps. The frequency is about 40KHz. The bandwidth of the signal is 10 kHz. The current capacity is 2.2 milli-Ampere. The power Capacity is 6.8 milli-Watt.

ASIC Chip: Also known as application-specific integrated circuit chip. It is a type of microchip that is designed for a specific application, such as a specific transmission protocol or a hand-held computer. It contains 10-bit ADC & DAC Converters, a Digital processing module, Analog Signal Conditioning Module and Relaxation Oscillator circuit. 

Fig 3: ASIC Chip for microelectronic pills

Temperature Silicon Diode-Sensor: It is one of the sensors that is there inside a microelectronic pill. Its function is to measure core body temperature and can prove to be useful in the detection of Tissue Inflammation and Ulcers.

Ion-Selective Field Effect Transistor: Also known as ISFET. It is used to measure ph. This is basically because it is coated with a material that is sensitive to chemical changes. The material used for fabricating the IFSET electrode is 4-inch p-type silicon wafer. This ph determination leads to the determination of reflux of the esophagus, inflammatory bowel disease, hypertension and the effect of GI-specific drugs on target organs.

Direct Gold Electrode: Conductivity is another attribute that is needed inside a microelectronic pill. This is because this attribute gives us insights into salt and water absorption, the breakup of organic matter into charged colloids, and bile secretion. The choice of material for this is gold because it has the best conductivity of all and therefore gives a more accurate value.

Three Electrode Electrochemical Cell: It is the main part of the electronic pill. It can calculate the rate of dissolved oxygen and also the amount of aerobic activity of bacteria in the large and small intestines.

Fig 4: Sensors inside the microelectronic pills

 

·        How does a microelectronic pill work?

All these components are connected to the ASIC chip. This ASIC chip is housed on two S48Ag2O batteries. These have a capacity of working for 35 hours, the supply voltage of 3.1 V and power consumption of 15.5 Mw. The sensors are housed on two chips which are located at the front end of the capsule. Both ph and oxygen sensors are hosted on two separate 8 NL electrolyte chambers which contain 0.1 concentrated KOH and 0.2% calcium alginate gel. The oxygen sensor is encapsulated in a 12µm thick film of Teflon and the ph sensor is protected by a similar thickness layer of Nafion. On top of these additional protection is given to these sensors by 15µm thick dialysis member of polycarbonate.

These sensors collect the data and are then transferred into an ASIC chip. This data is then sent to the base station. From this base station, doctors look at the readings and identify the problem.

Fig 5: Schematic Diagram of working of microelectronic pill

 

A new variant of microelectronic pill known as the visual pill makes use of the camera. By using the camera technology, the entire picture is captured and is sent using the wireless network. Earlier the pills that were available did not have high bandwidth because they made use of Medical Implant Communication Services (MICS) which had a bandwidth limit of 300KHz.

But the recent microelectronic pills are using UWB communications which are higher bandwidth technology. The speed available here is of 100Mbps. In medicinal circles, these pills are being referred to as “Magical Pills for Health Care”. 

Fig 6: A microelectronic pill

·              What are its advantages?

1.      It is extremely efficient in finding the malfunctioning areas and diseases within remote areas in our body like the infections of the gastrointestinal tract, pancreatic disease, inflammation of the bowel region, and esophagus reflux which is generally out of reach of traditional endoscopic devices.

2.      It can be used in any environment including the corrosive environment of the GI tract.

3.      Because it works in standby mode, therefore, consumes less power.

4.      It is small in size therefore it consumes less space.

5.      Because of its long battery, it can perform even long complicated operations easily.

6.      Because the range of transmission is only one meter, therefore, there is no noise interference.

·        What are its disadvantages?

1.      The ultrasonic and impendence techniques cannot be performed by it.

2.      It cannot detect radiation abnormalities.

3.      It is very expensive and is therefore not available in many regions.

4.      The size of the microelectronic pill is too big for babies to have. 

·        Conclusion:

A High-Capacity radio system is needed for a microelectronic pill to generally examine the digestive tract. But better methods and imaging techniques and also the use of larger bandwidth techniques like UWB antennas and receivers can be used to investigate the impact of technology on microelectronic pill technology. At higher frequencies, attenuation phenomenon occurs but this causes advantages as well. These include the flow of data without compressing, resulting in low power usage, less delay in real-time and increased picture resolution.