Bionics (also known as biomimetics, biognosis, biomimicry, or bionical creativity engineering) is the application of methods and systems found in nature to the study and design of engineering systems and modern technology.
Unfortunately, we are not bestowed with such unique regenerating capabilities that the starfish or the common lizard possess to grow back our arms and legs, restoring them to their original state. Stem cell research may be the answer, but no one knows for sure and, till then, it’s going to be artificial implants and this is where bionics comes into the picture. Let’s take a look at all that could possibly be done to restore or reconstruct a damaged human body.
In simple terms, when we think about bionics, it is generally more about prosthetic arms or leg enhancement worn outside the body and, to some extend, even implanted sensor devices inside the body, which are essentially enhanced to carry out certain routine tasks.These are essentially life systems that are powered by motors/actuators and sensory arrays. These send neural signals from affected part of the body to the brain, by which Individual are Able to perform certain tasks independently.This approach results in a hybrid systems combining biological and engineering parts, which can also be referred as cybernetic organism (cyborg). This definition of bionics is best known to the general public in reference to the television series The Six Million Dollar Man, in which the titular cyborg character is referred to as a "bionic man".In medicine, Bionics means the replacement or enhancement of organs or other body parts by mechanical versions. Bionic implants differ from mere prostheses by mimicking the original function very closely, or even surpassing it.Researchers say substituting wires for nerves is still many years away. But what about now? We've known that computers can talk directly to the brain but is there a way that the brain can talk directly to a computer?
"When we have a thought, we know that there's activity, electrical activity, in the brain," says Kennedy. "So we're trying to pick up some of that activity, and use that in our simple systems just to control a computer cursor."
Here's how it works. Commands from the brain are read through a brain implant, placed inside the motor cortex, the part of the brain that controls body movement. As the patient thinks about a movement, the electrode picks up a signal, amplifies it, then transmitts it through the skin to a computer.In experiments, a quadriplegic man has been able to move a computer cursor just by thinking about it, and a monkey has moved a robotic arm in the same way.Even though these devices are still in the future, bionics are already around us. A cochlear implant, a morphine pump, or even an artificial heart are examples of this merging of electronics and biology, steadily bridging the gap between human and machine.
The history of bionics begins from ancient mythological times, where soldiers were reported to have replaced their mutilated limbs with artificial ones made of iron ore and gone out to battle. But the present day scenario is influenced by a variety of disciplines, viz, robotics,
bioengineering, brain-computer interface and MEMS, with nanotechnology taking Centre stage because it applies detailed precision to engineer body organs and make them function along with human tissues. Brain gates are also used in bionic field. The last few decades have been wonderful years for technological advances, both for the medical and the electronics industry in the form of miniaturised electronic components, sophisticated microchips and advanced computer systems—all functionally embedded in the human body. This particular human-to-machine interface, aptly termed as ‘Cyborg entities’ or ‘Bionic bodies’, has helped people with physical disabilities (the differently abled) by providing them with artificial Limbs, cochlear implants, artificial muscles and other organs to perform tasks, enabling them to lead a notably better lifestyle.
What would the human body be without muscles? Just a dangling skeleton! Quite a scary thought! So in the case of damaged muscle, is there a possibility of generating new muscles altogether! Well, yes— one such scenario is the use of EAP or Electroactive Polymers. These are often referred to as artificial muscles and are increasingly being used by researchers to assist humans to overcome deformities. Yoseph Bar-Cohen of NASA’s Jet Propulsion
Laboratory is the first among equals in the research on EAP. He has conducted several experiments, and has found that these polymers respond exactly like our normal muscles under the influence of electrical stimulation and therefore are the most likely candidates for use in the human body as well as robotic areas of work. EAP can be coupled with MEMS to produce smart actuators.
The heart is the hardest working muscle in the human body. Located almost in the centre of the chest, the adult human heart is about the size of two fists held side-by-side. At an average rate of 80 times a minute, the heart beats around 115,000 times in a day or 42 million times in a year. During an average lifetime, the human heart will beat more than three billion times, pumping an amount of blood that equals about one million barrels.
The cardiovascular system, composed of heart and blood vessels, is responsible for circulating blood through the human body to supply uswith oxygen and nutrients.
1. Four chambers (two atria and two ventricles) that receive blood from the body and pump out blood to it.
2. Blood vessels, which compose a network of arteries and veins that carry blood from heart the body.
3. Four valves to prevent backward flow of blood.
4.An electrical system of the heart that controls how fast it beats.
Considerable defect: Due to the over-activity in the parasympathetic nervous system the pace of the heart decrease in the sympathetic nervous system, the pace or speed of heartbeat decreases. In this state the pulse rate of heart is termed as ‘bradycardia.’ Bionic
heart is designed with a view to command this
disease.There are areas in the heart called pacemakers’ that send electrical signals to the rest of the heart, setting the speed or pace of the heartbeat. They help it speed upduring exercise or hard work, and to slow down again during rest. If natural pacemakers are injured or fail to do their job, a miniaturized medical device called a ‘cardiac pacemaker’ can be implanted in the chest wall.Bionic heart, also referred to as ‘cardiac pacemaker,’ is device used to treat bradycardia (heart rate that is too slow). The pacemaker is implanted under the skin in the upper chest and is attached to one or two leads that are placed next to or in the heart muscle. The cardiac pacemaker system consists of a pulse generator (pacemaker), one or two pacing leads (for single-chamber or dual-chamber pacing), and programmer.It monitors the heart’s rate and rhythm, improving the way a patient feels. Using a small amount of electricity (similar to that used by a healthy heart), the pacemaker restores proper heart rate and rhythm.
Pulse generator:.The pulse generator is the ‘brain’ of the cardiac pacemaker system. basically, it comprises a hybrid circuit and batteries. The hybrid circuit, which is a miniature computer, is so small that it is assembled under a microscope. It contains all the components necessary to operate a state-of-the-art, sophisticated device. The batteries for pacemakers are designed to be small and flat so as to fit into the pacemaker case. These are made of lithium iodine, which gives them maximum power and a life span of up to twelve years.
The pulse generator case is made of titanium—a metal that is ten times as strong as steel, but much lighter to assemble the pulse generator. The hybrid circuit and battery are placed in the titanium case in a specially designed ‘clean room’ that has no static or dust in it. Once the hybrid and the battery are in the casing, the casing is welded shut with a high-powered laser beam. This laser beam gives the pulse generator a hermetic seal, which means that the device is air-and liquid-tight. After welding, the top ‘header,’ of the pacemaker is
attached and the entire device is covered in a thin layer of plastic. This plastic coating further seals the pacemaker. A typical pulse generator is very small in size, often less than an ounce (0.0648 gm) in weigh it, less than two inches (5cm) wide and a quarter-inch (6mm) thin. It is
implanted in the upper chest just below the skin near the collarbone.
Pacing leads.An artificial pacemaker is a small unit that consist of batteries to produce the electrical signals that make the heart pump. At tat lied to the battery are two electrode that connect it with the heart. Under local anaesthesia, the pacemaker is ii implanted under the skin of the chest , and the electrodes are threaded through a vein near the collarbone and guided to the heart muscle. Fixed-rate pacemaker produce constant electrical impulse: at a rate preset by the healthcare provider. Demand-type pacemakers have a special component that allows themto monitor the heart and generate impulses only when necessary.
Programmer:The programmer enables the physician to evaluate the pacemaker’s performance aid change its settings non-invasively The programming console is made up of carefully tested, complex circuit boards that are bonded together in a sturdy unit. To facilitate
programming, the software provides high-speed processing and easy operation. Atthe touch of a button, the unique automated follow-up feature delivers customized information on pacemaker. Inaction and cardiac activity for therapy that is specifically tailored to each patient.
Types of pacemaker
Single-chamber pacemaker: A single-chamber pacemaker uses one pacing lead, which means that the device paces only one chamber of the heart— the atrium or, more commonly, the ventricle.
Dual-chamber pacemakers. Dual-chamber pacemakersfeature two leads. One lead paces the atria and the second lead paces the ventricles. Pacing closely approximates the natural pacing of the heart.
Rate-responsive pacemakers. Available in single- and dual-chamber versions, rate-responsive pacemakers incorporate a sensor that automatically adjusts the pacing rate based on changes in the patient’s level of physical activity. As a person’s level of physical exertion increases,
so does his heart rate. A rate-responsive device enables the pacemaker to mimic a patient’s ‘natural pacemaker’ and its response to increased activity.There are a number of different types of sensors used in today’s pacemakers. Pacemakers use either the Omnisense accelerometer sensor or the fifth-generation Minute Ventilation sensor technology. The main benefit of rate-responsive therapy is that the patient’s own physiology controls the pacing rate rather than a preprogrammed value. With rate responsiveness, patients can continue very active lifestyles, even after pacemaker implantation.
Drawbacks of bionic heart
There are few side effects or surgical complications associated with artificial pacemakers but, like any manmade device, they are subject to failure. They do need to be checked regularly. All pacemakers are sensitive to electrical interference from microwaves and electrical generators and hence vary in degree, depending upon how well shielded they are.
How long a pacemaker lasts depends upon a number of factors, including the energy output settings and the time for which the pacemaker actually paces the heart. As the pacemaker is used, the energy in the battery depletes. During follow-tip monitoring, the physician receives
information about the amount of energy used by the pacemaker. As replacement time nears, he is alerted to the fact that the device has reached the recommended replacement time (RRT).
At this time, the physician will schedule a replacement procedure. RRT occurs well before the battery is fully depleted, providing the physician with plenty of time to plan for replacement.Because the pulse generator is hermetically sealed to prevent fluid leakage intc) the electronic components, it is impossible to open the device and replace only the battery. Thus, when a battery needs to be replaced, the entire pulse generator needs to be replaced. The physician reopens the pocket holding the pulse generator, disconnects the old device from its leads, attaches a new pulse generator to the existing leads, places the new device into the pocket and sutures the pocket closed. Sometimes it is necessary for the physician to place new leads.
5. Bionic ear
The human ear is a vulnerable organ. It is divided into three parts: the outer ear, the middle ear, which is made up of ear drum (tympanic membrane) and a chain of tiny bones called ‘ossicles’, and the inner ear (the cochlea). The cochlea contains hair cells
that, when stimulated, generate an electrical current in the auditory nerve, which then transmits the signal to the hearing centre of the brain.
Interaction between the ear and tile brain: When we hear music, a telephone call or a pin drop, our auditory system converts them into vibrations of the three middle ear bones. The last middle ear born is attached to the cochlea, which transforms vibrations into electric potentials inside the sensory hair cells. This creates action potentials in auditory fibres (axons), which the auditory pathway produces located it our brain.
Considerable defects:Each region of the ear can smith damage and even the most powerful hearing aids are in effective if the function of the inner ear is impaired. Sensorineurnal hearing loss (nerve deafness) is the common type of hearing loss.Damage is more often seen in hair cells, which send the sound information (electrical signals) to the hearing nerve. Damaged hair cells are unable to send the sound information to the hearing nerve and the person experiences hearing loss.In most cases of severe sensorineural hearing loss, a doctor or audiologist will recommend that the person be evaluated for a bionic ear.A bionic ear (cochlear implant) is an artificial hearing device, designed to produce useful hearing sensations by electrically stimulating nerves inside the inner ear. It bypasses missing or damaged hearing hair cells and delivers more sound information directly to the hearing nerve.
A multichannel cochlear implants consist of two main components: the cochlear implant package and electrode array (or receiver stimulator), and the speech processor and headset.
All the parts of the cochlear implant system are placed under the patient’s skin behind the ear during implant operation. The implant package (or receiver stimulator) contains electronic circuits that can control the flow of electrical pulses into the ear. It also contains an antenna that receives the radio frequency signal from the external coil and a magnet that holds the external coil in place. Attached to the package are wire leads that join to the electrodes.
The 22-electrode array is inserted into the shell-like structure in the inner ear known as cochlea. The ball electrode is placed under a muscle near the ear. There is also a plate electrode on the outside of the receiver-stimulator package. The outer parts of the implant system are worn externally. The coil is held in portion against the skin by a magnet and the microphone is worn behind the ear. The body-worn speech processor can be worn in a pocket, in a belt pouch or in a harness. The earlevel processor is worn behind the ear.
The microphone detects Hearing process using a cochlear: Sounds and speech. The information from the microphone is sent to the speech Processor, which analyses the information and converts it into an electrical code. The coded signal travels via a cable to the transmitting coil carry the coded signal into the device inside the implant. The implant package decodes the signal. The signal contains the information that determines how much electrical current will be sent to different electrodes. The appropriate amount of electrical current passes down the appropriate lead wires to the chosen electrodes. Once the nerve ending in coclea is stimulated, the message is send to the brain along the hearing nerve. The brain can then try to interpret the stimulation as a meaningful sound.
ADVANTAGES OF BIONIC EAR
1. Magnification of faint or distant sounds.
2. Increase sound up to 30 decibels.
3. Using omni directional microphone it becomes highly
4. Pinpoints sounds and their direction.
5. Loud sounds not amplified and automatic safety circuit provision.
6.The electronic nose
Artificial odour detectors have been built since the 1950s but without much success. In the past few years, progression in chip technology and pattern recognition has made electronic noses available for use in ai y different areas, from pollution let ‘ction to food processing.
The Institute of Olfactory Research at Warwick University developed the first prototype of electronic nose in the mid-80s. High-tech companies are now selling commercial versions of the ‘Warwick nose.
An electronic nose is a device used to analyze thecontent of air through the zlassification of odours. Although the electronic noses use today are far from replacing the human olfactory system, the possible uses for this technology are endless. Human noses are employed all over the world to test different products. Human noses to determine their quality and freshness examine the odours of rod products such as grains, wines, whiskey and fish. Perfumes and deodourants are also tested to see whether they are appealing to the nose. The sense of smell is even used by doctors, which help classify common disorders. Certain problems such as pneumonia o diabetes give patient’s breath or fluids characteristic odours can be noticed by a trained nose. Electronic nose could be employed for the same job with more possibility.
How an e-nose works?
Electronic/artificial noses are being developed for automatic detection and classification of odours, vapors and gases.An electronic nose has a chemical sensing system (sensor array or spectrometer) and a path recognition system (artificial network). During operation, a chemical vapor or odour is blown over the sensor array, the sensor signals are digitized and fed into the computer, and the artificial neural network (implemented in software) then identifies the chemical. The benefits of electronic noses include compactness, portability, real-time analysis and automation. The e-noses work on the same principle as the human nose. Humans detect odors using up to 650 types of receptors found on cells high in the nasal passages.Scientists are still not sure how the human nose processes smells but the receptors generate ‘smell prints’ of odors they receive, which then pass on this information to the brain where it is stored.
With e-noses, the premise is the same but sensors take the place of human cell receptors and a microprocessor takes the place of the brain. The e-nose also creates smell prints of the odors it receives, which are then stored in a database. If it receives the same imprint in the future, it will recognize that odor from its database and inform the user of the smell. In order to better understand how an electronic nose works, you must first understand what makes up a smell or an odor. The odors humans perceive are often combinations of many different chemicals. The odor of coffee is made up of hundreds of different molecules. These odourant molecules usually have three basic properties. They are small and light with molecular masses below 300 Da, polar and hydrophobic.
An electronic nose must be able to recognize these molecules and certain combinations of these molecules. The combination of a sensing system and a pattern recognition system helps to perform this function. In the past, gas chromatography and mass spectrometry were used as the sensing systems, which were usually expensive and time consuming. Today, the use of chemical sensors has been established to analyze odours.
Essentially each odour leaves characteristic pattern of certain compounds. ANNs can detect more chemicals than the number of sensors they are utilizing. These also allow for less selective, and therefore less expensive, chemical sensors.The sensors basically measure the change in voltage due to the presence of certain chemicals. The chemicals in the air change the oxygen content over the sensors. Change in the oxygen content changes the resistance
across the sensor, which can be measured as a voltage drop from the normal or standardised conditions. This analogue signal must then be translated into a digital signal by an analogue-to-digital converter (ADC) for the computer to understand the information. The number of odour signatures the system can recognise depends on the number of sensors used and the
number of grey levels in the converter. The maximum signature number is given by g”, where ‘n’ is the number of sensors and ‘g’ is the number of grey levels. A 10-bit converter has a grey level value of ‘1024,’ so an array of three sensors could yield over a billion different signatures. Unfortunately, the actual number is far below this value.
In most of today’s machines, there is an extra piece in between the sensor and the computer. Electronic noses usually utilise a data preprocessor that is analogous to the olfactory bulb in the human olfactory system. The preprocessor compresses the signals and amplifies the
output to reduce noise and improve the sensitivity of the sensor. The digital signals are now ready to be analysed by the computer.The computer essentially compounds all the different
vectors from the change in resistance across the sensors and sums them into one or more characteristic vectors. The artificial neural networks are trained to distinguish certain odour from certain chemical combination. Pattern recognition is gained through giving the network known odours and classifying them with a signature. Then the nose is tested to see how well the ANN has learned. The results can be adjusted through experimentation.
The Pacific Northwest National Laboratory is exploring the technologies required to perform environment restoration and waste management in a cost-effective manner. This effort includes the development of portable, inexpensive systems capable of realtime identification of contaminants in the field. As part of this effort, ANNs are being combined with chemical sensor arrays and spectrometers for use in prototype electronic noses. Environmental applications of electronic noses include identification of toxic wastes, analysis of fuel mixtures, detection of oil leakages, identification of household odours, air-quality monitoring, factory emission monitoring and testing of ground water for odours.
Because the sense of smell is important to physicians, an electronic nose has applicability as a diagnostic tool. Electronic noses can examine odours from the body and identify possible problems. Odours in the breath can be indicative of gastrointestinal problems, sinus problems, infections, diabetes and liver problems. Infected wounds and tissues emit distinctive odours, which can be detected by an electronic nose. Odours coming from body
fluids such as blood and urine indicate liver and bladder problems.
An electronic nose for examining wound infections is under testing at South Manchester University Hospital. In similar applications, ANNs have also been used to track
glucose levels in diabetics, determine ion levels in body fluids and detect pathological conditions such as tuberculosis. While the inclusion of visual, aural and tactile senses into telepresent systems is widespread, the sense of smell has been largely ignored. Recently, Pacific Northwest National Laboratory proposed a more futuristic application of electronic noses for telesurgery. The electronic nose would identitify odours in the remote surgical environment. The identified odours would then be electronically transmitted to the other site, where an odour generation system would recreate them.
Currently, the biggest market for electronic noses is the food industry. Electronic noses can be used to augment or replace panels of human experts. These can also reduce the amount of analytical chemistry performed in food production, especially when qualitative results will do. Existing applications include inspection of food by odour, grading quality of food by odour, fish inspection, fermentation control, checking mayonnaise for rancidity,automated flavor control, monitoring cheese ripening, verifying whether orange juice is natural, beverage container inspection, plastic-wrap testing for containing odour of onions, microwave oven cooking control and whiskey grading.
Business and other applications
In the future world of Nathan Lewis, bomb squads won’t need dogs. They’ll have electronic sniffers to find explosives. The portable noses will also uncover sub-standard food, and sound an alarm if a car’s brake fluid smells deficient. This versatility intrigues NASA, says Lewis. No one knows what new gas may appear inside the space shuttle, but the Caltech nose could learn what the spacecraft smells like under normal conditions, and then ring a bell if the odours change. So the nose nickname I pinocchio— may someday fly to the moon. But today, it’s sniffing beer. Pinocchio is made up of small polymer sponges lined up like toothbrush bristles. Each sponge holds a different electrical a inductor and is connected through a myriad of wires.
When beer is introduced to the sensor, the sponges, swell and all of the conductors react to the ethanol, yeast and other scents But each conductor reacts differently. With the help of computer, Lewis ‘fingerprints’ the smell. The next time he holds a beer near Pinocchio, computer will show the same pattern
More exciting are the possible medical applications:
Warwick University scientists are researching the use of electronic noses to diagnose illness by smelling patients breath, and have recently been awarded a grant from the European Union (EU) to investigate the possibility of installing tiny electronic noses in phone receivers, so patients can simply breathe into the phone and wait for a diagnosis. A similar smell-transmission device may soon allow surfers on the Internet to ‘wake up and smell the coffee’ quite literally.
Researchers are investigating the use of breath analysis to identify the stages of the female menstrual cycle: the ability of electronic noses to detect ovulation could benefit both fertility treatment and birth control. Our unique body odour may become an alternative form
of identification, signaling the end of credit-card fraud, forgotten or misappropriated personal identification number (PIN), fake ID cards, etc. The Association for Payment Clearing Services, an organization set up to find solutions to these problems, is investigating the use of
electronic noses in banks, and companies may soon be able to replace security entry systems involving cards and codes with a device that recognizes each employee’s personal odour.
Different researchers have created e-noses for specific applications. The Libra nose, for example, created by an Italian team at Rome’s Tor Vergata University, was created to deted illnesses. It works on the basis that an illness creates certain chemical changes in the body that we cannot smell. But a machine trained to smell out certain scents could detect these odours. In the future, it could lead to early diagnosis of illnesses such as lung cancer, which perhaps could then be caught at a curable stage..
The z nose introduced by ECI available in either bench top handheld form is made up of single patened sensor, programmable gate array to control the sensor and a direct heated 1m length of capillary chromatography column. Within 10 seconds, it can measure the concentration of individual chemicals contained within odours through the use of 100’s of virtual chemical sensors.
The e-noses available so far are not as sensitive as the human nose, but these offer significant advantages.
1.they do not get bored with repetitive smelling tasks.
2.unpleasant smells such as industrial wastes etc does not make the electronic sniffer feel sick.
3.their smelling capacity does not get altered according to mood or unpredictable human factors.
4.it has a particular standard for each type of smell. 5.there is no health risk because of smelling toxic smells.
2.atmospheric moisture and humidity also result improper working of e-nose.
Pharmaceutical taste-assessment typically requires a large, trained taste panel, and sophisticated interpretation. The tests may require the same health safeguards as a clinical trial. All told, a properly conducted taste test adds time and money to the development process.We process taste at three levels: the receptor level, the circuit level, and the perceptual level. At the receptor level are approximately 10,000 chemoreceptor or taste buds, residing primarily on the tongue, with some delocalized receptors at the back of the throat. Clearly, any complication or insolubilization technique that inhibits interaction between the drug and the taste buds may also affect API dissolution and absorption profiles. It is thus critical to develop ODT performance and taste formulation together. Because pharmaceutical taste-assessment can demand large panels and elaborate analysis and raise safety and scheduling concerns, a full taste program can be time-consuming and expensive.Alternatively, the “taste study” may be reduced to an informal gathering of executives, who reach consensus on the best formulation without considering statistical significance or protocol. Data derived by such a method is highly subjective, limited, and potentially biased. An electronic tasting apparatus such as the e-tongue (Alpha M.O.S., Toulouse, France) offers one solution to these challenges. This technique compresses timelines and lets researchers gather taste and dissolution data simultaneously. Telescoping these steps reduces development time, development costs, subjectivity, bias, and safety concerns.
Key benefits of e-tongue taste evaluation
● helping quantify bitterness of drug actives when limited basic taste information
is available, especially if the drug supply is limited
● developing suitable matching bitter placebos for blinded clinical testing
● developing optimized taste-masked formulations
● measuring efficiency of complexation/coating within formulation
● serving a quality control function for flavored product and excipient.
The e-tongue mirrors the three levels of biological taste recognition:
the receptor level (taste buds in humans, probe membranes in the e-tongue); the circuit level (neural transmission in humans, transducer in the e-tongue) and the perceptual level(cognition in the thalamus in humans, computer and statistical analysis in the e-tongue).At the receptor level, the e-tongue uses a seven-sensor probeassembly to detect dissolved organic and inorganic compounds.
The probes consist of a silicon transistor with proprietary organic coatings, which govern the probe’s sensitivity and selectivity.Measurement is potentiometric, with readings taken against an Ag/AgCl reference electrode. Each probe is cross-selective to allow coverage of full taste profile.At the circuit level, the system samples, quantifies, digitizes, and records potential-meter readings. At the perceptual level, taste cognition happens not in theprobe, but in the computer, where the e-tongue’s statistical software interprets the sensor data into taste patterns. Depending on the study design, data analysis can produce a variety of information.Initial taste optimization studies explore the formulation properties with principle component analysis (PCA), discriminating among subtle differences in the formulation to display a large “distance” between samples For a new chemical entity for which no data are available regarding the taste of the compound, other than perhaps some information solicited from the synthetic chemist, it is often insightful to quantify bitterness as a function of known bitter agents. This approach can be taken using discriminate factorial analysis In this case, the API bitterness is comparable to that of a known concentration of urea. Knowing this gives the formulator a reference for comparison and a starting point for taste optimization. Moreover, this activity can provide a bitter matching placebo formulation for blinded clinical trials-tongue analysis can reveal the “distance” between formulation tastes. This data can suggest and quantify simple bitterness-reducing strategies such as adding low levels of sodium.
8. Bionic eye
Twenty-five million people worldwide are blind because one layer of cells on their retinas no longer works. By 2020, the figure is expected to double. Using information technology, researchers are developing an artificial retina. Their efforts have already started yielding results. For example, with the help of an experimental artificial retina, a man who has been blind for 50 years is now able to see. Artificial retina: the basics An artificial silicon retina (ASR) microchip has been developed to treat vision loss. It is a silicon chip 2 mm in diameter and 25 microns thick—less than the thickness of a human hair. It contains approximately 5000 microscopic solar cells, called ‘micro photodiodes,’ each with its own stimulating electrode.
These micro photodiodes convert the Light energy from images into electrochemical
impulses that stimulate the remaining functional cells of the retina in patients with age-related macular degeneration and retinitis pigmentosa types of conditions.The ASR microchip is powered solely by incident light and does not require the use of external wires or bat teries. When surgically implanted under the retina—in a location known as the ‘subretinal space’—it produces visual signals similar to those produced by the
photoreceptor layer. From their sub-retinal location, these artificial ‘photoelectric’ signals from the ASR microchip are in a position to induce biological visual signals in the remaining functional retinal cells, which may be processed and sent via the nerve to the brain.
The artificial retina system comprises of an array of artificial retinas comprises a detector element, a fiber-optic element directing incoming visible light or particular intensity to said detector element, emitting in output signal as a function of the intensity of the incoming visible light, and a coupler to couple the output signal of said detector element to the retina.
The artificial retina system is preferably hosed in a plastic enclosure made of material similar in composition to that of artificial lenses used in cataract lens replacements.Other advancement in the technique uses an integrated circuit (IC), which is coupled to the photodiode (or IR detector) and the coupler. The IC amplifies the output signal of the photodiode (or IR detector to and transmits the amplified output signal to the coupler.
A microlens is placed in front of the fibre optic element to focus incoming light onto the fibre-optic element. Additionally, a colour filter is placed in front of the microlens to pass light corresponding to a particular colour to the microlens. Alternatively, a coloured fibre-optic element that transmits light of a particular colour can be used, obviating the need to place a colour filter in front of the microlens. The coupler used is a scanning tunneling microscope (STM) tip. The STM tip receive an electrical signal from the photodiode (or IR detector) and transmits the electrical signal to the retinal nerve. STM tips are basically metal wires that are very finely sharpened at one end. ‘he tip is made of platinum. The unsharpened end of the tip is coupled to the photodiode (or IR detector), while the sharpened end is directed towards the retina for releasing current at a specific point on the retina. Another technology uses a metal P sheet In this embodiment, the metal sheet is disposed between the photodiode (or IR detector ) and retinal nerve. the metal sheet receives the output from the second photodiode (or IR detector) and in response transmits an electrical signal to the retinal nerves. In a preferred embodiment, the metal sheet is made of copper and has a curvature
corresponding to the curvature of the retina at the area near which the metal sheet is placed. Visual signals are captured by a small video camera in the eyeglasses of the blind person using a charge-coupled device (CCD) sensor. The CCD sensor digitizes the visual images intercepted by the camera. The digital representations of the images are then beamed via laser pulses onto a microchip implanted in the eye and processed through a microcomputer worn on a belt. The signals are transmitted to the electrode array in the eye.
The array stimulates optical nerves, which then carry a signal to the brain. The first prototype implants contain 16 electrodes. The next prototype, with 50 to 100 electrodes, is in preclinical trials. The project’s ‘next-generation’ device would have as many as 1000 electrodes, and researchers hope that it would allow the users to see images. Electrical stimulation of the visual cortex causes blind subjects to perceive small points of light, known as ‘phoshenes’ researchers are running tests to determine the map of patients phosphenes.the images that a patient sees composed of asmall number of white dots that he otherwise a dark visual field. The arrangement of these dots corresponds roughly to what is viewed by a small electronic pinhole camera affixed to an eyeglass.
Organizations working on artificial retina include The Blindness Foundation Group’s Research Center at Johns Hopkins University, Harvard Medical School, Massachusetts Institute of Technology and University of Utah, which is developing a silicon chip to be implanted in the visual cortex of the brain.
Two ways of stimulating the retina for artificial vision are currently well developed. One is sub-retinal stimulation, in which a sheet containing a microphotodiode array is inserted into the subretinal space to compensate for lost photoreceptor function and stimulate the outer retinal network. The other is epiretinal stimulation, in which retinal ganglion cells and their axons are stimulated with a multielectrode array attached to the vitreous side of the retina.
The researchers have built a prototype that contains 256 pixels, and are developing a more complete silicon- based system that can be used in autonomous robots and smart sensors. They also aim at using the silicon retina in cameras or remote monitoring for safety, identification and biometrics purposes.
Sub-retinal vs epi-retinal stimulation
1.Fixing the electrode array is easier with sub-retinal stimulation than epiretinal stimulation.
3. Sub-retinal stimulation needs a lot more elect I ii power than epiretinal stimulator. Sub-retinal -stimulation can use retinal circuitry. Epiretlnal stimulation requires the processing of visual information into speific patterns for stimulation of retinal ganglion cells.
One common drawback of both types of implants is that the implanted electrodes are, directly attached to the retina, so the risk of retinal damage at implantation is inevitable. Still a long way to go!The video camera is and complicated image processing software that are used to give machines the ability to see are relatively expensive. Since the devit e is not entirely implanted in the eye likely to suffer from reliability problems. The user of the implant muscles either continuously wear the eyeglass with the camera disposed thereon n keep it nearby for wearing when needed. It may be difficult expect the laser beam to reliably rnttin focused on the implant in the eye The silicon retina provides information about the edges of images rather than a wl el’ picture. Edge information is sufficient just for detecting and trt k hg objects. It will take 10years for tile silicon retina to be stable for use practically. Application Using optical output ‘will have years or so until optical available for interchip communication.
When signaI reach the visual cortex via the optical layer they influence not only the sum of tile brain but many layers of cells beneath it. The nerve again branches, the branches branch, those branches branch and so on. In addition, every cell influences the behaviour of the cells around it, and in turn each cell is influenced by a combination of inputs from many places. To add to the complexity, the entire system changes many times each second
Scope of improvement
The image processing approach requires the image to be captured by a sensor and digitised. This image is then usually preprocessed to reduce noise. After these stages, an information reduction approach can be used to provide essential environmental information, and/or attempt to understand objects in tile environment. Subjective improvements include improved perception of brightness, contrast, colour, movement, shape, resolotion and visual
field size. Scene understanding (high-level vision) is concerned with identifying features and extracting information. The scene structure is still there to a degree, but it is idealized or reduced. An example application might be to identify a bus stop, fire hydrant or traffic light. It may also be useful to know the distance to the object (number of steps, or time at current walking speed). Due to the limited number of phosphenes that can be generated by the current technology, it may be better to present a symbolic representation.
For example, a small part of the grid (perhaps 5x5) could be used for information on obstacle locations in the current environment. Auditory information could also be provided in natural language. A scene description mode could be useful.
Visual prosthesis constraints
Number of phosplienes. Current technoiogy limits the number of phosphenes that can be provided to tile patient. Additionally, the size, shape and brightness of phosphenes are not predictable, although recent work in a 4x4 retinal prosthesis shows promise iii overcoming these problems.
Real-time processing. A visual prosthesis system needs to perform in real time. However, this has been problematic for other image-based mobility systems, particularly those which are stereo-vision based. One way of providing real-time processing may be to restrict the field of view of the camera, although this would restrict the amount of preview (or time to anticipate problems) available to a blind traveler.
Obviously, the first users of artificial retina technology will be blind people. It will be a wonderful boon that will restore eyesight for millions of people. Once the resolution of an artificial retina exceeds that of the human eye and it becomes possible to combine it with zoom capability, artificial eye implants will also become attractive for people with perfectly healthy eyes.
If the future artificial retinas can be made from thin films that can shift their molecular configurations on-the-fly, it may be possible to even reconfigure (by straining eye muscles in some trained pattern) the retinas to look at different parts of the light spectrum as well. Imagine, instance, soldiers or police shifting their eyesight into the infrared when on a dangerous night-time operation. Or imagine just any person wanting to up his light sensitivity when outside at night or in a room with little available light.The researchers have built a prototype that contains 256 pixels, and are working to make a more complete silicon-based system that can be used in autonomous robots and smart sensors. The silicon retina can also be used in cameras for remote monitoring for safety, identification and biometrics purposes. Sufficiently advanced technologies developed to treat
diseases will inevitably morph into technologies that will enhance function. Research on artificial implants for blindness is laying the groundwork for the eventual development of vastly superior, artificially enhanced eyesight.
9. Bionic leg
Imagine a prosthetic knee that automatically adapts to the individual’s personal walking style and continually learns while optimizing control over time. by sensing knee position and loads applied to the limb at a rate of 1000 times each second, the knee is capable of analyzing the user’s gait and delivering the proper amount of resistance during each step.
Dynamic learning software continues to assist in optimizing this performance as the individual progresses to higher levels of function.
Leave fatigue at the door. The advanced software and processing technology coupled with the efficiency of magnetorheologic (MR) actuation means natural motion is no longer a relic of fiction. Through the reaction of forces with magnetism, walking effort is reduced to minimum levels for the amputee. Resistance is applied only when resistance is necessary. Walk longer. Walk farther.
Leave fear at the door. Force and position sensors detect proper foot placement for reliable and consistent stance release when it is desired.
Traverse and descend surfaces with increased confidence and decreased stress. Focus on the tasks of the day and not the task of walking. Walk with trust. Walk with confidence.It’s not a dream, but the first born product of the revolution. The RHEO KNEE™ by Ossur is the first microprocessor swing and stance knee system to utilize the power of artificial intelligence.
State-of-the-art bionic technology instantly adapts to real-world walking conditions. By utilizing customized resistance when resistance is required, the RHEO KNEE empowers the individual to quickly regain confidence in his or her ability to walk at any desired speed and traverse any terrain. Walk naturally. Walk comfortably.
The rheo knee
Continuous adaptation to gait
Dynamic learning matrix algorithm™ (dlma):The RHEO KNEE utilizes a software-based artificial intelligence to learn an individual’s walking style. From the moment the first step is taken, the RHEO KNEE is watching and beginning to calculate optimal values for swing phase resistance to match every walking speed. From small steps in a crowded restaurant to rapidly crossing a busy intersection, movement is matched consistently and accurately. As the range of walking speed and activity increases, the RHEO KNEE adapts appropriately. Through constant monitoring and optimization, the RHEO KNEE provides a virtual prosthetic adjustment to ensure that the individual’s walking style is maintained with each step.
Microprocessor controlled stance: Through advanced sensing and processing, the RHEO KNEE provides multiple safeguards against inadvertent stance release. Stance support is only released when the individual desires release of support, thus providing enhanced security when compared to existing mechanical systems. Disturbances in the walking path are automatically recognized and stance support is instantly activated to protect the individual from a potential stumble and fall. This results in the reduction of fear and anxiety while increasing confidence when walking.
extended-life and fast, easy-charging battery: The RHEO KNEE’s single Lithium Ion battery lasts up to 48 hours on a single charge. Equally important, recharging takes just 2 to 4 hours and can be done at home or on the road. The RHEO KNEE’s power switch also extends battery life by allowing the user to turn the RHEO KNEE off when it’s not in use.
The rheo knee
Natural and efficient motion
magnetorheologic (mr) fluid actuator: This advanced technology uses magnetic fields to vary the RHEO KNEE’s resistance. From firm and unyielding support when standing to light and free movement when turning a corner or walking in confined spaces, response is exceptionally smooth and fast. Unlike existing hydraulic systems, MR resistance is activated only when the individual needs it, allowing more natural and effortless motion.
Simplicity of operation
rheo logic software: This icon-based programming software runs on an HP iPAQ palm-based computer. The simple interface makes loading and modifying individual profiles easy and fast. This all adds up to a minimum amount of downtime and a maximum amount of time spent enjoying life.
Energy efficiency and comfort
Compatibility with flex-foot: The compact design of the RHEO KNEE allows for excellent compatibility with the highest energy storage and return foot available. This combination of legendary foot dynamics allows for a revolutionary transfemoral prosthetic system that makes walking natural, effortless and comfortable.
The University’s Role in Creating a Better Artificial Arm .A multi-disciplinary team of University of Utah researchers will focus on developing and testing a “peripheral nerve
interface” - an implanted device that would relay nerve impulses from nerves in the residual limb to a small computer worn on a belt and then to the bionic arm.
The University’s Role in Creating a Better Artificial Arm.
That would allow a person to move the artificial limb like a real one. Sensors in the artificial arm would send signals to the computer and on to the interface device, which would relay the signals to nerves in the remainder of the amputated arm and then to the brain, allowing the person using it to sense the arm’s motion and location, and to feel objects with the mechanical hand and fingers. A multi-disciplinary team of University of Utah researchers will focus on developing and testing a “peripheral nerve interface” - an implanted device that would relay nerve impulses from nerves in the residual limb to a small computer worn on a belt and then to the bionic arm.
That would allow a person to move the artificial limb like a real one. Sensors in the artificial arm would send signals to the computer and on to the interface device, which would relay the signals to nerves in the remainder of the amputated arm and then to the brain, allowing the person using it to sense the arm’s motion and location, and to feel objects with the mechanical hand and fingers .Researchers at other institutions, meanwhile,
will develop the prosthetic arm itself and will study other kinds of neural interfaces that could operate the bionic arm, including a device implanted to receive signals from the brain instead of nerves in the residual limb.
Clark stated, “This new arm will provide sensory feedback to make the arm feel like a person’s own arm. Existing prosthetic arms are so hard to use, and feel so unnatural, that sometimes people just don’t use them. They put them on the closet shelf.”
As principal investigator for the Utah part of the prosthetic arm program,
Clark will oversee the project. He also will participate particularly in interface device with hand-and-arm surgeon Douglas T. Hutchinson, an associate professor of orthopedics, and Nicholas Brown, a research assistant professor in orthopedic surgery. Other University of Utah co-investigators are Normann, who will enhance the electrode array’s capabilities for operating the bionic arm; bioengineering Professor Patrick Tresco , who will test the interface device and its components to ensure they are safe when implanted in people; Reid Harrison, an assistant professor of electrical and computer engineering, who will develop miniature electronic components such as amplifiers and signal processors; and Florian Solzbacher, an assistant professor of electrical and computer engineering, who will fabricate the array’s components, put them together and encapsulate the device so it can survive when implanted in people.
11.FUTURE OF BIONICS
These bionic organs can de used to develop a superhuman. Artificial eye can be used to view the images beyond the obstacles. Artificial nose can be used to detect the poisons, symptoms of various diseases. Mind power can be used to control the whole systems. The military persons to lift huge weights and run can use artificial legs and hands and run very fast. With e-nose can smell the presence of enemies? Certain video games would be developed which gives us the real presence in the game.
Bionics has helped disabled persons to enjoy their life. Their application to military, medicine, business etc helped the human species to live an easier and simpler life. Certain bionic devices are life saving devices.Hopefully scientists will be able to overcome all the issues, making it possible to develop an immortal superhuman.