Implementation of multichannel sensors for remote biomedical applications

K J Sree Bhargava

II B.Tech.,ECE, Gudlavalleru Engineering College,Gudlavalleru.

Mobile No –9494382847,email:jagannadhbhargav@gmail.com.

ABSTRACT

A micro electronic pill is basically a multi channel sensor used for remote bio medical measurements using microtechnology this has been developed for the internal study and detection of diseases and abnormalities in the gastro intestinal GI tract where restricted access prevents the use of traditional endoscopy the measurement parameters for detection include real time remote recording of temperature, pH, conductivity and dissolved oxygen in the GI tract This paper with the design of the micro electronic pill which mainly consists of an outer biocompatible capsule encasing 4 channel micro sensors a control chip, a discrete component radio transmitter and 2 silver oxide cells.

I.INTRODUCTION

Our body is a sensitive system. At some situations, doctors can’t easily detect diseases and hence it becomes too late to cure it. Use of electronic pill helps us to easily detect the diseases and can take sudden action against it. In 1972, Professor John Cooper and Dr. Eric Johannessen from Glasgow University, U.K has led to the development of electronic pill. It is a medical monitoring system. Measurement

parameters of electronic pills include temperature analysis, pH measurements, conductivity and dissolved oxygen. And they can also capture images and sent it into a system. Electronic pills are swallowable. It has a 16mm diameter, a length of 55mm and 5gram weight. This pill is covered by chemically resistant polyether-terketone (PEEK) coating.

Fig. A wireless electronic pill system with antenna

dimensions.

When it moves through gastro-intestinal track it starts to detect diseases and abnormalities. A small electronic pill can easily reach areas such as small intestine and large intestine and can deliver real time information to an external system. Total information will be displayed in a

monitor. The electronic pill travels to the digestive system, collects data and sends it into the computer with a distance of 1 meter and more.

II.STRUCTURE OF DEVICE:

Main parts of electronic pills are four sensors, an ASIC chip, a radio, transmitter and a power source, LED, Camera

II(i).RADIO TRANSMITTER:

Radio transmitter transmits all the data from base station to the receiving end. Size of the radio transmitter is about 8x4x3 mm. Frequency shift Keying is the modulation scheme used in this radio transmitter. Data transfer rate is 1 Kbps. Frequency is about 40.01 KHz at 20o C. 10 KHz is the bandwidth of the signal that was generated by the radio transmitter. It consumes 2.2 mA of current at 6.8 mW power.

II(ii).CONTROL CHIP:An array consisting of both temperature sensor & pH sensor platforms were cut from the wafer & attached onto 100-µm- thick glass cover slip cured on a hot plate. The plate acts as a temporary carrier to

assist handling of the device during level 1 of lithography whenthe electric connections tracks, electrodes bonding pads are defined. Bonding pads provide

electrical contact to the external

electronic circuit

II(iii).BIO-COMPATIBLECAPSULE ENCASING MICRO SENSOR:

This device consists of 4 microelectronic sensors. They are:

SILICON DIODE which is used to identify the body temperature. They are the commonly used temperature sensors in electronic equipments. This temperature sensor is attached in the substrate. The main advantage of this sensor is that, it is a silicon integrated circuit at very low cost.

Fig. Circuit diagram for pH sensor

Ion selective Field Effect transistor:

ISFET is used for measuring ion concentration in solution. There are so many diseases which occur due to abnormal pH level. They are; reflux of oesophagus, inflammatory bowel disease, hypertension, activity of fermenting bacteria, pancreatic disease, level of acid excretion and effect of GI specific drugs on target organs.

Direct Contact Gold Electrode:

It helps to measure conductivity. Gold has the best conductivity compared to other elements, so it gives accurate value. Conductivity measures are done by measuring the contents of water and salt absorption, breakdown of organic compounds into charged colloids and the bile secretion.

Three-Electrode Electrochemical Cell;

It is the main sensor in electronic pill. It is used to calculate rate of dissolved oxygen and identify the activity of aerobic bacteria in small intestine and large intestine

Fig.3-electrode electrochemical cell

II(iv).DIAGNISING DISEASE WITH CAMERA

The capsule contains a camera, an LED light, a battery and a built-in antenna. The antenna transmits the images to a small recording unit that the patient wears on their waist during the study. The unit is

slim and lightweight and allows patients to go about their everyday activities with ease and comfort.”As the capsule travels through the esophagus, stomach and small intestine, it takes photographs rapidly. The photographs are transmitted to the recording unit worn by the patient. At the end of the study, the photographs are downloaded from the receiver into a computer and reviewed by the specialists and Doctors. Using computer software, a video is made out of the images captured during the procedure. And this camera able to take photos in 360 degrees with high clarity and UWB telemetry can send up to 100 frame per second (fps).

Fig.diagnising internal parts with camera pill

III.WORKING OF DEVICE

All All these sensors are controlled by application specific integrated circuit. Also, all the other components of the electronic pill are connected to ASIC.ASIC consist of analog signal conditioning, 10bit analog to digital convertor/digital to analog convertor, relaxation oscillator circuit (OSC) and digital signal processing circuit. All these circuits are powered by two SR48 Ag2O

batteries. It has 35 hours working capacity and supply voltage is about 3.1V. Power consumption is 15.5 mW. SENSORS are fabricated on two silicon chips that are located at the front end of the capsule. Both pH and oxygen sensors are enclosed by two separate 8 nL electrolyte chambers containing a 0.1 KOH solution retained in a 0.2% calcium alginate gel.  Oxygen sensor is covered by 12 µm thick film of Teflon and the pH sensor is covered by 12 µm thick film of nafion. Both sensors are protected by a 15 µm thick dialysis membrane of polycarbonate. All the data is collected by ASIC and sent to the base station. From this base station doctors identify the problem

Visual based electronic pill consists of a camera. By using this camera entire picture can be captured and it is send through a wireless connection. Earlier, the electronic pills have narrow band transmission and have limited number of camera pixels. The allowable bandwidth in Medical Implant Communication Services (MICS) is only 300 KHz. It is very difficult to transmit high quality videos during real time transmission. In UWB

communication (wideband technology), data rate transmission is equal to or higher

Fig. Working of the device

than 100 Mbps.After diagnosis, the

electronic pill can come out through bowel movement. In medical field other name for electronic pill is “Magical pill for health care”, because it is very easy to detect disease infected areas or any other abnormalities. Mainly electronic pills areclassified into two types; first one includes Camera, which collect disease detected areas and send it to the system, and the second one contains only Sensors. These sensors measure pH level, temperature, oxygen level etc

IV.Merits,Demerits and other applications of device

MERITS

Capsule endoscopy may show tumours in the small intestine or other parts of the digestive tract.

It is beneficial to detect the diseases and malfunctioning in the remote areas of gastro intestinal track just like pancreatic disease, inflammatory bowel disease, activity of fermented bacteria, acidic level and esophagus reflux which is out of reach for conventional endoscopic device.

It can be used in corrosive surrounding of GI tract.

It consumes very less power as it operates in Programmable Standby Mode.

Its practical application is very simple as it has very small in size.

The battery lasts for 40 hours which is sufficient to carry out any type of complete internal diagnosis.

DISADVANTAGES

It is unable to detect radiation abnormalities.

The treatment through Micro Pill is very expensive and is not available in many regions.

The size of pill is small but it is not as small that can be digested by small babies

.OTHER APPLICATIONS

The generic nature of microelectronic pill makes it adaptable for use to environmental and industrial applications ,pollutiondetection, control of fermentation process and inspection of pipelines. The integration of radiation sensors and the application of indirect imaging technologies such as ultra sound and impedance tomography, will improve the detection of tissue abnormalities and radiation treatment associated with cancer and chronic inflammation.

V.FUTURE SCOPE:

Temperature sensors will not only be used to measure changes in the body core temperature, but may also identify local changes associated with tissue inflammation and ulcers. Likewise, the pH sensor may be used for the determination of the presence of pathological conditions associated with abnormal pH levels, particularly those associated with pancreatic disease and hypertension, inflammatory bowel disease, the activity of fermenting bacteria, the level of acid excretion, reflux to the oesophagus, and the effect of GI specific drugs on target organs.

The conductivity sensor will be used to monitor the contents of the GI tract by measuring water and salt absorption, bile secretion and the breakdown of organic components into charged colloids. Finally, the oxygen sensor will measure the oxygen gradient from the proximal to the distal GI tract.

This will, in future enable a variety of syndromes to be investigated including the growth of aerobic bacteria or bacterial infection concomitant with low oxygen tension, as well as the role of oxygen in the formation of radicals causing cellular injury and pathophysiological conditions (inflammation and gastric ulceration). The implementation of a generic oxygen sensor will also enable the development of first generation enzyme linked amperometric biosensors, thus greatly extending the range of future applications to include, e.g., glucose and lactate sensing, as well as immunosensing protocols.

VI.CONCLUSION:

A high capacity radio system is currently necessary for electronic pill technology in order to visually examine the digestive track wireless with better and detailed images Techniques and methodologies have been presented in this document for the use of wideband technology in a miniaturized electronic pill to provide a high capacity wireless channel. A prototyping system including UWB transmitter/receiver and antennas has been developed to investigate the feasibility of a high data rata transmission for the electronic pill technology. Integration of antenna with the UWB transmitter electronics has been considered in a capsule shaped structure. Although it is known that tissue imposes strong attenuation at higher frequencies, we have shown there are some advantages to use wideband technology. Due to the high data rate capacity (e.g. 100 Mbps), a wideband electronic pill can transmit raw video data without any compressing, resulting low-power, less delay in real-time and increased picture resolution. With a high definition camera such as 32.0megapixels, UWB telemetry can send up to 100 frame per second (fps). We believe that the wideband pill helpful for the development of internal study of body parts and fast diagnosing of disease.

REFERENCES:

[1] R. Salmore, “Our heritage: A history of gastroenterology and gastroenterology nursing,” Gastroenterol. Nursing, vol. 21, no. 2, pp. 40–43, 1998.

[2] K. M. Reavis and W. S. Melvin, “Advanced endoscopic technologies,” Surg. Endos., vol. 22, pp. 1533–1546, 2008.

[3] A. Moglia, A. Menciassi, P. Dario, and P. Cuschieri, “A clinical update: Endoscopy of small bowel tumors,” Lancet, vol. 370, pp. 114–116, 2007.

[4] G. Iddan and P. Swain, “History and development of capsule endoscopy,” Gastrointest. Endos., vol. 14, pp. 1–9, 2004.

[5] A. Loeve, P. Breedveld, and J. Dankelman, “Scopes too flexible and too stiff,” IEEE Pulse, vol. 1, no. 6, pp. 2154–2287, Dec. 2010.

[6] C. P. Swain, F. Gong, and T. N. Millis, “Wireless transmission of a color television moving image from the stomach using a miniature CCD camera, light source and microwave transmitter,” Gut, vol. 39, no. A26, 1996, (abstract).

[7] A. Moglia, A. Menciassi, M. O. Schurr, and P. Dario, “Wireless capsule endoscopy: From diagnostic devices to multipurpose robotic systems,” Biomed. Microdevices, vol. 9, pp. 235–243, 2007.

[8] J. Bradbury, “Journey of the center of the body,” Lancet, vol. 356, p. 2074, 2000.

[9] P. Valdastri, R. J. Webster, III, C. Quaglia, M. Quirini, A. Menciassi, and P. Dario, “A new mechanism for mesoscale legged locomotion in compliant tubular environments,” IEEE Trans. Robot., vol. 25, no. 5, pp. 1047–1057, Oct. 2009

[10]. Djemouai, and M. Sawan, “Wiley Encyclopedia of Electrical and Electronics Engineering,” vol. 17, pp. 413, 1999.

[11] E. A. Johannessen, L. Wang, L. Cui, T. Tang, M. Ahmadian, A.Astaras, S. Reid, P. Yam, A. Murray, B. Flynn, S. Beaumont, D.Cumming, and J. Cooper, Implementation of multichannel sensors for remote biomedical measurements in a microsystem formats,” IEEE Transactions on Biomedical Engineering, vol. 51, no. 3, pp. 525-535, March 2004.

[12] P. Mohseni, K. Najafi, S. J. Eliades, and X. Wang, “Wireless multichannel biopotential recording using an integrated FM telemetry circuit,” IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 13, no. 3, pp. 263-271, September 2005.

[13] M. R. Haider, S. K. Islam, and M. Zhang, “A low-power signal-processing unit for in vivo monitoring and transmission of sensor signal,” Sensors & Transducers, vol. 84, issue 10, pp. 1625-1632, October 2007.

[14] H. S.Wolff, “The radio pill,” New Scientist, vol. 12, pp. 419–421, 1961. S. J. Meldrum, B. W. Watson, H. C. Riddle, R. L. Bown, and G. E. Sladen, “pH profile of gut as measured by radiotelemetry capsule,” Br. Med. J., vol. 2, pp. 104–106, 1972.

[15] D. F. Evans, G. Pye, R. Bramley, A. G. Clark, T. J. Dyson, and J. D. Hardcastle, “Measurement of gastrointestinal pH profiles in normal ambulant human subjects,” Gut, vol. 29, no. 8, pp. 1035–1041, Aug. 1988.

[16] R. H. Colson, B. W. Watson, P. D. Fairlclough, J. A. Walker-Smith, C. A. Campell, D. Bellamy, and S. M. Hinsull, “An accurate, long-term, pH sensitive radio pill for ingestion and implantation,” Biotelem. Pat. Mon., vol. 8, no. 4, pp. 213–227, 1981.