 Welcome to the NPTEL lecture series. So, today we are introducing a new course on bioelectricity. So, the course consists of 40 lectures and the course has been divided into 5 different modules and each module is fairly independent of each other. I will try to treat each module as a independent cluster. So, that at one point which each module you want to really go through first may help you, barring aside some of the very fundamental basics. The basic requirements what I kind of expect from this that up to your high school you have gone through some of the very very basics of electricity that the charge is being carried in different forms it could be an ionic charge, it could be flow of electrons. So, the way and this much fundamental understanding of Ohm's law which is v is equal to I R at any point of time voltage is equal to product of current and resistance. As long as these simple concept or concept of capacitor what is a capacitor and what is an amplifier that is good enough for you to you know appreciate this course what is the philosophy of this course. So, today what I will do I will give you some basic idea about the philosophy of this course and then I will move on to the overall layout of this course why bioelectricity there is electricity all over the place. So, all of you are aware of that your I am talking because sound energy is converted into electrical signals electrical impulses I am standing in this room it is completely lighted because that is the source of electricity which is taking care of it. So, what is the origin of electricity electricity is very much a part and parcel of the biological systems if you look all around you. So, for example, think of the nerve impulses those are nothing electrical impulses which are flowing in your body the way your cardiac beat cardiac cells beat the way your heart beats that is nothing, but flow of electrical impulses which regulates the flow of blood all over your body the memory accusation phenomena it is an electrical phenomena the motor actions the propagation of nerve impulse the way your muscles respond to some kind of a stretch some kind of a strain. So, there is a there is a translation of mechanical energy into electrical signals or say for example, in the case of touch me not leaf you touch the leaf it force it is a electrical phenomena it is a bioelectrical phenomena think of the situation of venus fly trap the which catches the insects these are the plants which catch is insects. So, basically the insect comes touches on certain surfaces of the flower and the flower starts closing it is another electrical phenomena. So, there are some touch sensors which senses that impulse and translate that impulse into electrical signals and the end result is the trap gets closed and the insects gets trapped inside that whole flower and it is being finally digested and used for food. So, these are the carnivorous plants similarly there are several inanimate objects which exhibit electrical phenomena something like back in the hornet nest this is back in 1970s there are significant research which was done it is in the hornet nest it has been observed that hornet nest has a thermoregulatory property and the thermoregulation is driven by the hornet cell cap which is present there. So, in other words this hornet cap is a thermoelectric membrane those of you from your basics high school if you remember something like peltier effect seabake effect where which are thermoelectric. So, you give thermal energy it is translated into electrical energy or vice versa you give electrical energy to a material it is converted into thermal energy. So, these kind of thermoelectric materials are being seen across nature apart from it you will see the examples of fireflies or think of situation of photosynthesis where solar energy is leading to the emission of an electron and that electron eventually basically a photon is being absorbed and electron is being emitted and then that electron hops through inside the plant cell and leads to the generation of food which is under photosynthesis photo means light synthesis is a process by which bigger molecules are being synthesized. So, all these phenomena what you look across nature are bioelectrical phenomena and they have been exploited or they have been understood from different perspective. So, bioelectricity is a very broad term first to start off with the whole body is governed by bioelectrical phenomena and understanding of this individual bioelectrical phenomena has profound implications in understanding our whole existence. So, if you look the way it has progressed in last two centuries I would say definitely one and a half centuries the progress in measurement of charges electrical impulses leads to the development of the whole field of bioelectricity look back the time of Volta look back the time of when the impulse was recorded from the frogs muscle the twitch which was recorded. So, these are long back Volta Galvani these are some of the like stalwarts or you can say the founder father of the whole field of electricity. So, it is it dates back to that time from the time actually as a matter of fact electricity was initially being very correctly observed in biological systems it is long back. And then of course the whole field of electrical engineering developed and parallely the progress of bioelectrical phenomena or understanding bioelectricity became a function of the different devices we got developed in the domain of electricity and electronics especially in the later half of the last century post 1950s with the discovery of silicon based electronics there happened a tremendous improvement in the in the development of amplifier circuits or in the development of different electronics electro meter which could measure current at the peak or nano ampere level with decent amount of accuracy. So, if we look at the one side is all this phenomena which is taken place there is other side where we are talking about all the different measurement techniques because whenever we talk about biological systems essentially we are measuring currents of peak or ampere nano ampere into likewise very low currents we are talking about we are not talking about a grid where huge huge amount of currents are flowing through we are talking about something which is fairly low. So, in order to measure such current you need different kind of devices you cannot afford to use your regular multimeter to do those recordings. So, you need very high impedance devices which can measure those. So, if you look back since nineteen or from seventeen hundred I would say the field has take quantum jumps with the discovery of newer and newer measuring techniques and currently with the advancement of amplifiers high end amplifiers we are able to measure extremely low electrical potentials in all different forms of systems or different systems which are existing in nature. So, a part of the course will concentrate on all these different kind of devices what will be dealing with then will be dealing with any electrical phenomena has a direct link that this could be used for energy harvesting. So, we will talk in detail of different energy harvesting modules which are being currently under in development specially you have to realize that more and more we are heading for sustainable energy and our biggest hope is learning from biology the sustainable route to harvest energy. So, we will be talking in depth about different modules like artificial leaf how from the leaf there are people who are trying to emulate the photosynthetic power of the leaf to harvest energy one of the topics which will be going to go through extensively apart from it will be talking about the examples where the different dyes different colored dyes of nature are being used like hibiscus are being used to develop a dye sensitize solar cells. So, these are the molecules which are all across the nature and they have a tendency to absorb light and eject an electron and that electron could be funneled and could be used for running any kind of low power electronic devices at this stage. So, we will be talking about those small dye sensitize solar cells will be talking about backpack based systems where mechanical energy is being translated into electrical energy which has been is in progress for a long time because those of you or grandfather or you know great grandfather must be riding a bicycle which has a dynamo attached to it. So, basically while the bicycle they are riding. So, the mechanical energy which is generated while the bicycle is moving is translated into electrical energy using the dynamo and you could see that without any source of battery or anything the light is glowing in the night. So, if you look back and go online or ask your great grandfather or grandfather they will tell you know that is how they used to travel with a bicycle when in the evenings where there is no street light or something like that. So, there are several examples where electrical phenomena has been extensively used for harvesting energy apart from it. We will be talking about man machine interface where we will be talking about how the say for example, a person is having a blindness. So, basically that means the image plate or the retina of that individual is not functioning is there a way we could implant and synthetic or electronic camera in front of the eyes. So, that the image which is formed in the eyes could be interface with the brain. So, we totally bypass the sensory modality because this has been successful in cochlear implant in the ears. So, those who cannot hear they put a synthetic cochlea or a bio electronic cochlea or basically an electronic gadget which could sense in other word you are essentially putting a mic out in your ear and that mic is being connected to your brain. So, whatsoever you are hearing is bypassing your ear because your ear drum is no more your ear drum and the cochlear structure is no more really functional. So, you bypass everything and you interface it to the brain. So, that is possible it is another way or say for example, is there a way for spinal cord injury patient we could implant some electronic devices with at the zone or at the site of injury which could help to help this person to you know get back some of the lost degree of freedom in terms of movement is it possible. We will be talking about here some of the seminal experiments which have been done by people or scientists across the world where they could dictate a monkey using a using a computer so or vice versa or. So, basically in other word how man is interacting with the machine. So, that is another area which will be highlighting. So, this course encompasses a wide range of different topics which has been put under 5 different headings and the goal is to give you a flare of bioelectricity and inspire you to explore this subject for the future because future lies in all form of sustainable growth, sustainable development, sustainable energy because we cannot rampantly misuse the natural resources for our good we have to be very careful and critical because you have seen places like Fukushima or you know places like Chernobyl the kind of nuclear disasters have taken place or several other places which are not really reported that. So, we need different other sources of energy and some of our hopes are lying in using biological systems for energy harvesting in the field of solar energy where we are pretty much hitting the roof with the silicon base crystalline silicon based electronics because currently in the lab conditions the maximum efficiency you could get is around 17 percent and the cost recovery is a very challenging problem because the amount of intense investment which is being done in developing silicon based electronics system, silicon based silicon manufacturing system is enormous could be really you know bypass that could there be newer and newer material. So, we will talk about some of these newer materials which are there in the radar, but needs lot more research from you people apart from it another area which people are trying to explore is the way biological system which is a by product of photosynthesis how they are splitting water because this is a way how hydrogen can be generated and eventually hydrogen could be used as a source of energy. So, what are the different techniques by which water could be split what are the different molecules which could be developed very cheap. So, in case of biology the leaves contain something called a manganese cluster is a cluster of manganese which remain in different oxidation state and the water molecule gets trapped it is being stripped off and you get the oxygen and as a by product and this whole process people are trying to emulate using different kind of complexes which will emulate a manganese cluster. So, this is a wide range of bioelectrical phenomena and the other side is where people are developing different kind of super capacitors from biological materials will be talking about this some of the most recent advances where people have developed super capacitors from biological system people are trying to develop bio batteries using different kind of sources. So, these are these all like whenever you pick up a text book on this there is hardly any text book which exclusively deal with all these things it is a very broad subject. So, this is this 40 brief 40 lectures is basically to give you a flair of the broadness of the field and the beauty of this whole field it is a stand alone subject and it is a very passionate subject if you look at it I mean there are so many things what you can do so many product which can develop. So, many fundamental studies which could be done, but it needs a different kind of flair to appreciate all these things. So, with this introduction what I will do I will give you the outline of this what are the what are the different modules I have pretty much talked it out, but I have not given you a systematic layout that how will be dealing with this different modules and what are the different things will be dealing with. So, let me give you an overall outline of the different modules and from there we will talk about how we are going to deal with this individual modules. So, welcome again so course title is bioelectricity. So, I told you there are five different modules we are dealing with. So, let me module and put the topics what are the different topics we are dealing with. So, module one that is essentially introduction to the subject. So, coming to module one coming back to module one. So, here basically what we will do module one we will have three lectures two or three lectures you know this kind of flexible. I will introduce you with some of the different examples of nature what is happening in diagrammatic manner and based on what I am drawing now and we will try to get a former definition of bioelectricity and from there we will lay the course how we are going to follow in the subsequent section. So, coming back so let me put another column here which is classes or lecture. So, there will be two to three lectures out here in the module one which is the introduction module two will be dealing with bioelectricity in animals insects and fishes. So, pretty much all in the animal kingdom. So, here I am keeping it very broad we will talk about the we will introduce ourselves with the membrane potential in the animal world then we will talk about the nerve propagation which is taking place in the animal world after that we will be talking about the action potentials we will talk about memory accusation processes then we will talk about the reflex circuits we will talk about vision how the image is being formed then we will talk about the hearing and mind it all these will again come back. So, parallely what I will do what are the cochlear implants and all these things I will include both of them simultaneously and we will be talking about the different situations how spinal cord injury situations could be you know could be bypassed. So, this is all about the bioelectrical phenomena. So, we will have approximately 10 to 13 lectures devoted to this area and from here we will move on to the bioelectricity bioelectricity in plants. So, here we will talk about some of the plants like you know touch sensors or pressure sensors likewise especially in plants like Mimosa pudica touch me not and the insectivorous plants like you know those which traps the insect and we will partly introduce you to the whole photosynthetic machinery here how the photosynthesis is taking place how the electrical events within the plant leads to the generation of energy. So, this is where we will be can be devoting around 6 to 10 lectures. So, then from there we will move on to module 4 module 4 is measurements of electrical impulse measurement techniques using different devices this is a section which we will cover around approximately around 5 lectures. So, in this section we will be talking about electro meters those of you remember during your school days may be standard 7th or 8 we introduced to Gould if electro meter you remember that is a charge you rub something and you see the charge movement. So, currently those old electro meters have become electronic devices now it has translated into electronic kind of a and they are very high end devices in terms of their measuring capacity they can measure around you know nano ampere pico ampere currents with highest fidelity. So, we will talk about the electro meters we will talk about the high gain amplifiers we will talk about the patch clamp setup where which are used for measuring the electrical impulses or the flow of current through a single channel. So, in that context we will talk about the single channel recording we will talk about the development of different fluorescent molecules which could help to image electrical phenomena something like calcium imaging or there are molecules which have been developed by some really very intense research has been done in developing some of these fluorescent molecules which changes their color with the change in the potential. So, we will talk about some of those techniques apart from it we will talk about the voltage clamp and current clamp under the patch clamp then we will talk about if time permits we will talk a little bit about the electrochemical measurement techniques which helps in the bio electrical processes. So, this is our module 4. So, from here we move on to module 5 module 5 is a very interesting module this module will take you from one end to the other end this is the module where we will be talking about man machine interface we will talk about prosthetic retina in terms of putting a camera in front of the eyes and interfacing it with the brain we will talk about cochlear implant here we will talk about the different electronic gadgets which are being used for deep brain stimulation and the idea of brain chip idea of spinal cord chip what is the current status of research and here I will introduce you to some really very good materials and I will introduce you to some of the some of the stalwarts in this field whose work you can read and kind of get an idea about how the progresses are being made in this phenomenally beautiful area and very very challenging area because the very moment we talk about. So, here I will highlight something the very moment we talk about man machine interface in other word we are talking about you have to engage in electrode inside your system and electrode is a foreign material. So, that needs intense understanding of material properties of the material which you are introducing into the body and that is a whole field in its own authority because when we talk about like you know you put a deep brain stimulator or a electrode inside your brain it is a totally totally foreign material which is entering how you handle that it is not easy it is not easy really even to think in that way like you know what a big deal it is fairly challenging and that is where lies the major challenge of prosthetic bioelectronics the prosthesis area of bioelectronics where people really are developing. So, there is one there are groups which are developing newer and newer biocompatible electrode materials which could be put inside the body without much immune reaction because you have to realize that you cannot pull that out electrode or gadget time to time and you know clean it have been put it back it is there and it has to be there for a while it is just like you are putting a pacemaker it is another area we should be dealing with a pacemaker out here. So, to ensure the pacemaker does not have a immune reaction or something of that sort. So, these are the things we will be talking about in this section part one of it. So, essentially I could divide this into two parts here is part one this part one will be dealing with prosthesis mostly and in the mostly in the animal kingdom, but I will be dealing the another part the. So, the part two will be dealing with how energy could be harvested from the biological systems that falls under bioenergy and that is where we will be talking about as I was mentioning in the earlier half of this lecture that there will be talking about the disensitized solar cell artificial leaf backpack energies and deriving energy from inanimate object if possible we will talk about the fireflies and we will talk about other different dyes which are found all across nature which has potential to be exploited for electronics applications. So, that will be essentially our part two where we will be talking about bioenergy and this is the part which will be dealing in another 10 to 13 lectures. So, this is in as a summary I could say how the course will progress we will talk about I have partly introduced due to the subject I will probably take one more class to introduce in depth of these different aspects how we are going to move on the whole graphical understanding of it that how all these things are happening and then I will be moving on to the individual module and as I have told you that you can study this individual module as standalone module I will try to keep it as independent as possible. So, that you do not need to follow a sequence really if you know the introduction and the broad outline of the course you can pick up any of any of the modules and do a complete in depth study of it without any problem. So, apart from it what I will request people that in every class I will try to give you some of the references which because of course, because of copyright reasons and everything I cannot really hand out like that, but you people can independently download them I will give you the link and I will try to go through those that will be extremely essential if you if you invest little bit of your time to go through them. So, that will help you to understand some of these processes and that is the reason why I am not even giving you some of these hands outs because there are copyright infringement and I do not want to do that. So, there will be materials which I will be providing I will be providing the link we will have to go online and search or download the link is functional with your system and definitely you will be able to download some of these materials which will be really helpful in this course and just while concluding this first lecture I will tell you just brush up some of the basics of electricity that will help you to appreciate this course in greater detail and you have to be bit more imaginative for this course this is not really a information based course that there are informations I am you know transferring informations to you it is more of a imagination this course needs bit of a little higher imaginative power to think in a very global perspective, but how things are going to change in next 100 years things are in the phase of changing is just we are not seeing them, but things are changing across the world. So, I will expect you to be slightly more imaginative to you know visualize the changes what are coming on our way. So, the way we see life it is going to change in next 100 years big time. So, with this whole different fine modules of the course how we are going to progress. So, I will close in here and we will come back with our second lecture which is part of the introduction and there we will be talking about the graphical layout of the course. Thank you.