Microelectronic Pill Essay Example for Free

microelectronic Pill Essay1 ABSTRACTThe contrivance of transistor enabled the first use of radiometry capsules, which used simple circuits for the internal study of the gastro-intestinal (GI) tract. They couldnt be used as they could transmit only from a single channel and also due to the coat of the components. They also suffered from light reliability, low sensitivity and short lifetimes of the devices. This led to the industry of single-channel telemetry capsules for the staining of disease and brachydactylousities in the GI tract where restricted atomic number 18a prevented the use of traditional endoscopy. They were later modified as they had the disadvantage of victimization laboratory type sensors such as the glass pH electrodes, impedance thermometers, etc.They were also of very large size. The later modification is similar to the above instrument but is smaller in size due to the application of existing semiconductor fabrication technologies. These technologies led to the formation of MICROELECTRONIC PILL. Microelectronic pill is basically a multichannel sensor used for remote bio medical exam measurements using micro technology. This is used for the real time measurement arguings such as temperature, pH, conductivity and dissolved oxygen. The sensors ar fabricated using electron smooth and photolithographic pattern integration and were nurseled by an application specific integrated circuit (ASIC).2 INTRODUCTIONWhen Microelectronic pill is swallowed, then it will travel through the Gastro Intestinal Tract simultaneously perform multi parameter in situ physiological analysis After completing its mission it will come out of the remains by normal bowel movement The pill is 16mm in diameter 55mm long weighing near 5 gram It records parameters like temperature, pH, Conductivity, Dissolved Oxygen in real time. It measures the body core temperature. also compensates with the temperature induced signal changes in other sensors. It also identifies local changes associated with TISSUE INFLAMMATION ULCERS.3 utilise science USED IN MICROELECTRONIC PILLION-SELECTIVE FIELD EFFECT TRANSISTOR(ISFET) The ISFET measures pH. It cannister reveal pathological conditions associated with abnormal pH levels These abnormalities include Pancreatic disease Hypertension Inflammatory bowel disease The activity of agitation bacteria The level of acid excretion Reflux of oesophagus Effect of GI specific drugs on target organs. The pair of direct contact Gold electrodes measures conductivity, by measuring the contents of water common salt absorption, bile secretion the breakdown of organic components into charged colloids etc. in the GI tract. Since the gold has outstrip conductivity among all the elements, Therefore it gives true value of conductivity as measured. DIRECT CONTACT fortunate ELECTRODE The three electrode electrochemical cell detects the level of dissolved oxygen in solution.It measures the oxygen gradient from th e proximal to the distal GI Tract It investigates Growth of aerobic or bacterial infection Formation of radicals create cellular injury pathophysiological conditions like inflammation Gastric ulceration. It develops generation enzymes linked with amperometric biosensors. ASIC The ASIC (Application Specific Integrated Circuit) is the control unit that connects together other components of the micro system. It contains an parallel signal conditioning module run the sensors, 10-bit analogue to digital (ADC) digital to analogue (DAC) converters, digital data processing module The temperature circuitry bias the diode at incessant 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. The conductivity circuit operates at D.C. It measures the resistance across the electrode pair as an inverse function of solution condu ctivity. An incorporated potentiostat circuit operates the O 2 sensor with a 10 bit DAC controlling the working electrode authority w.r.t the reference Analogue signals are sequenced through a multiplexer before being digitized by ADC. ASIC sensors consume 5.3 mW world-beater corresponding to 1.7 mA of current. restrict CHIP Size of transmitter = 8 ? 5 ? 3 mm Modulation Scheme = frequence Shift Keying (FSK) Data Transfer Rate = 1 kbps Frequency = 40.01 MHz at 20 C Bandwidth of the signal generated 10 KHz It consumes 6.8 mW power at 2.2 mA of current.RADIO TRANSMITTOR4ExperimentalThe electronic pill comprise a biocompatible capsule, which consists of a chemically resistant polyether-terketone (PEEK) coating, the four microfabricated sensors, the ASIC control chip and a discrete component radio transmitter (Fig. 1). The unit I powered by two SR44 Ag2O batteries (3.1 V), which provides an operating time of 35 hours at the rated power consumption of 15 mW. The sensors were fabricat ed on two recognize 55 mm2 silicon chips located at the front end of the capsule. The temperature sensor is embedded in the substrate, whereas the conductivity sensor is directly exposed to the surroundings.The pH and oxygen sensors were enclosed in two separate 8 nL electrolyte chambers containing a 0.1M KOH solution retained in a 0.2 % calcium alginate gel. The electrolyte maintains a stable potential of the integrated Ag/AgCl reference electrodes used by the two sensors. The oxygen and pH sensor are covered by a 12 ?m thick film of teflon and nafion respectively, and protected by a 15 ?m thick dialysis membrane of polycarbonate. The signals were conditioned by the ASIC and then transmitted to a local receiver (base station) at 40.01 MHz prior to data acquisition on a PC. The applied simplex communication link, based on a direct sequence spread spectrum communication system, can handle data from several pills at the same time.4 APPLICATIONIt is used in the medical diagnosis of ge stro-intestial tract disease.5 CONCLUSIONThe electronic pill will be further miniaturised for pitying ingestion by the incorporation of the transmitter on silicon and a reduction in power consumption by the implementation of a standby modus and serial bitstream data compression. The integration of radiation sensors and the application of indirect imaging technologies such as ultrasound and impedance tomography will improve the detection of tissue abnormalities and radiology treatment associated with cancer and chronic inflammation.6 REFERENCES1 www.wikipedia.com2 www.seminar-only.com3 Cane, C., I. Gracia, and A. Merlos, Microelectronics Journal.