Right. To work. Thank you David thank you for the nice introduction and invitation to give a talk here. This is really on a to me. So I mean as David already told it from Ken it's all stated here is that it's just down twenty miles north from here Georgia Tech. We are small undergraduate school. But I mean when I say the small student population wise we are actually larger in Georgia Tech. We have twenty three thousand but technology wise not. So my name is again for our brewer. I did. All my studies back in India and then did my research at all over the state my bag on these mainly you know again in chemistry doing might be the Aidid lot of synthesis of inorganic Smalling organic molecules and X. ray crystallography. That was one of my space alleged. But later on when I came to Colorado State I did not do any. Like solid state or extra diffraction but I mainly focused on an M R solution state and them are starting from fruit on carbon. We need a minimum force for us and them are born in them are several different nuclei so that's where I learned a lot of solution chemistry. So when I joined Kennesaw State in two thousand and eight we did some new directions then I started working. We first started we lived prisms if you were criminally originally prisms. We having a liver by layer and then want to detect inorganic metal based drugs like Cisplatin or some other routine IYAM compounds in mean analogs of Cisplatin and then study how they interact with the loop in violator and then release of those molecules and these nanoparticle project that I stirred it maybe about an year ago last year. So for me. So that's why I really would request everyone to you know. Keep your expectation will be down because I'm very need you in this field. I'm still learning. OK. So today I'm going to talk about metal based nano particles mainly goal nano particles even though I work with some silver based nano particles and then how you can detect some of the toxins or pollutants using simple techniques like E.V.A.'s or Roman spectroscopy I would like to give you a little bag on about. You know a little kind of rephrase or about how these techniques work like Roman and how the surface. Plus and resonance was. So simple outlined here I'm going to talk about metal nano particles and little bit of spectroscopy bag ground and whether they are recent applications and little bit of literature review. So that you know what's going on even though you some of you already know and then talk about the synthesis and then a particle and then they're characterizing did. Excellent. And finally what is the future direction for from a recess. And then No question is why I'm interested in particles. So when I started this vessel project as even I had some experience in there. I were suffering some troubles. You know instrumentation techniques that we did not have at Kennesaw State. That's why I got in contact with they've got it here and Research Center and you know got the. Availability of this facility at Enter C. So then I thought OK let's see these two particles and then use these techniques that available here really available here so that we do know in a particular project and other good thing about this nano particle is it has surface plausible resonance explain a little bit about the surface plasma resonance in a minute. And then you can detect some of those you know it's called Naked Eye detection even without any spectroscopy technique you can actually by looking at the color chains by a naked eye. You can tell something is going on right. And it's highly sensitive low cost and it's a solution based sensors. OK there is a sensor called biosensor. Buke or that instrument. Available at enter see that also does similar you know based on these surface Blossman resonance. But dead you know it's time consuming but when we work we didn't enter particles. It's as I said highly sensitive and less time consuming and cost effective. And what happens in this case how we use this technique when you have been nano particles solution and you want to detect in an allied maybe a pollutant maybe an explosive material or maybe a toxic material then you just put it into your nanoparticle solution and then. You see a color change or aggregation based on that you can actually detect right and other very good technique is called the Surface and handsome and spectroscopy or almond scattering so simply it's called certs some of you or maybe all of you familiar with the name Roman spectroscopy so I'll give you a little bag on about Roman spectroscopy So what happens in case of source meaning. Why do we say surface and hence if you have a metal nanoparticle in presence of metal nanoparticle if your analyze it is very close to the metal surface then its signal gets enhanced about ten to fourteen to fifteen orders a main issue. OK so that's why it's called surface and hence in presence of metal surface most commonly like silver and gold and of our little surface or just regular metal gold or silver surface right. And so it can be a very good platform to detect molecules small molecules and very quickly and inexpensive way and it is very reliable The reason is Roman is basically like a fingerprint up a molecule right. The gives a fingerprint of a molecule. And then. Now the question is What is F B R S B R is basically it gives you a signal absorption based on the electrons on the metal surface when incident radiation interact with the you know all those conducting electrons on the metal surface and it produces a broad absorbs and then and we see is depending upon either it's gold or silver intensities different so Silver has more better extremes and cold fusion by the way. And what happens as you can see here I have a little cartoon here it's the metal nanoparticle core and then those natively. Electrons called conducts an electron and they actually couple with the incident electromagnetic radiation and that's how it produces absorbs absorption band. And then and that particular incident is called the Surface plasma resonance that means resonance between the the electronic field generated by those magnetic field generated by the incident radiation and the electrons on the surface. OK. And now why is that important. Now it's very sensitive to size this particular absorption band the surface but Blossman resonance or the S.P.R. band is. Sensitive to the size. What how big your nanoparticle is if you change the size of the nano particles that's if stored to ride right. So I have a little couple specter of that I would like to show you here that what happens to the size of the Nano particle there's some random sizes. OK I'm going to talk about exact size right now but this is how the spectrum looks like for a goal in a particle reapers and the goal in a particle. This is how I'm really presenting it is this size for this particular band. If this size increases like the red one. So it's safe to ride. OK so. So this is what happens as the size increases the particle it's to the right right. So from there you can actually tell size is increasing or decreasing for the nanoparticle now there is another technique. It's called Dynamic Light Scattering you can use that to actually determine the size distribution of those nano particles but if this is a very quick indication that size is changing form into those nano particles. OK. Now what about Raman spectroscopy so Romans where gross could be is traditionally it was discovered in nine hundred. Twenty eight. Actually the first work has been done but received in India. He actually got the Nobel Prize for this particular discovery in one hundred thirty. He and his student Christian and actually world. This is the first Roman spectrograph OK that they got the first data. It's kind of IT WOULDN'T thing. There isn't. I'm a little bit nostalgic about this instrument. I have seen this and. The institute where I did my Ph D. in India they have displayed a killer instrument there. OK. So here is the institution that I work. It's called Indian Association for the cultivation of science and David already mentioned that I did my Ph D. from the Purina versity we are affiliated to each other. Purina versity but did all the work here and in our early age nineteen hundred Roman was a part time researcher in the same institute and then he got this discovery there. OK I wanted to mention but the thing is that I've kind of feel like Personally I did not do any justice to Roman being from the same institute. So last year when I started on a particular project I said OK let's do some. Roman spectroscopy and third or maybe this is a tribute to the great scientists. OK. Now how Roman spectroscopy works as I said earlier it's a very weak technique that's why even though it was discovered so early. It was not a very popular technique because it's a very very weak. So every molecule where it is in so loosen or in the solid state have their own five reasons why did you vibrate and when light incident on that material or the sample then it actually scatter lives there are two types of scaring one is called elastic one is called In the last three now if you collect those in love to kill the scattered light we see this very. It's a small fragment. And you actually create the Roman spectrum. OK this is how we works. So. And then this is a very non destructive technique that means you produce Sembilan and he going to reuse for other other characterization. OK it's nondestructive. And can be collected in glass plus the water and some other solvent so. So this is very easy technique. And the now the problem is it was weak. So that's why it was more popular now recently in the technique called the surface meaning surface and hence Roman spectroscopy or Roman scattering here if you have a probe molecule or a Roman active molecule very close to a surface and then what happens. Its surface its intensity increases standard fourteen to fifteen so. So that's called the enhancement right. And let's see how it works now there are three different mechanisms. How did enhancement happens first one is called electromagnetic enhancement when incidentally leisure. You know falls on the sample then what happens it excites those electrons on the surface of the mantle land or that we see surface plus months it excites those and as a result it creates a magnetic field electromagnetic field and that magnetic field can spread up to twenty nanometer from the surface. OK. When the incident. Laser falls on the surface. And the other mechanism is called choice transfer enhancement meaning you have the you have the electrons right. In the analyzed and then the metal surface meaning the Romanek the probe and then the metal surface you have electrons if there is an electron transfer between the metal surface and then the an allied order molecule then it gets and hands but that enhancement is not matched and a hundred times. But this one is most important the electromagnetic enhancement and the third type is resonance enhancement meaning the wavelength of your laser incidental ID were using and wavelength of where day your sample absorbs if it is close and then it gets under some order of and handsome and so if this tree together then you get a Hughes enhanced man and you get a very good signal or very intense signal compared to its regular Roman signal. OK So this is how the technique works. Now I would like to show you a little cartoon from this particular reference very nice and reference how it works. So this is the incident laser on the sample right. Some of them will be absorbed some of them will be transmitted and some of them in the scared say this is the. In love and the one the time in the moon one we see is the in the last exterior and that generates the Raman spectrum. OK So this is very we now when you have a metal nanoparticle like gold or silver in that case it could be prismatic C. or spherical fav like a nano rod. Then if you are a molecule is in these close proximity where the magnetic field generation a magnetic field is happening like this red area represents the intense magnetic field as you can see this bar here Red means high. Magnetic Field yellow is low and then blue area is the zero memetic field right. Due to the interaction between the leisure and then the surface electrons are right. So if your molecule is right here in this area red area then you get a Hughes enhancement right. So I would like to show the spectrum. This one the first one is this molecule. This is a spectrum by the way for period the molecule your family or we didn't write it basically depends in-ring you replace one carbon. In nitrogen right. So the theory Dean and it has a very nice signal around one thousand centimeter inverse that signal and hands at that if it is in here. But if it is in between the rain in the yellow that signal is enhanced little bit you can see it. Even at P.P.M. level ppm concentration right. Now if it is in the yellow reason you may may may or may not see it but if it is outside in the blue reason then you don't even see where this is how the technique works. And now the question is you can Kennie use it for solider solution both yes you can. So if you are metal in a particle is dispersed in water or other solvent. Then if your molecule of interest order active molecule is close to your metal surface the Red Dog reproduce the a metal nanoparticle if it is close to the metal surface then its intensity will be enhanced. And you can even do in solid state or anything coded on the metal surface like gold or silver or any other metal surface where and hence mean of course. So the list of things is the incidentally again. And these guys are an allied already Roman active group and see your. Substrate so nano particles are actually considered as substrate because there is where you are the probe will bind and then some signal will enhance it. We see substrate and the other ones you are molecule of interest will call an allied right. And then this is the simple matter X. and easy detection to the instrument and here is this or spectra right. You get a very signal enhancement in that. All right so I'm going to talk about one more technique an M.R.I. thing. Some of you are already from. It an M R I do not have any slide for that but I would just like to mention out on the basic in between. When I talk about the end of March spectrum in my tone. Later on. Now the question is What are the reason that the case and based on the S.B. are banned the goal nanoparticle and then the search detection using gold or silver nanoparticles right. So some of them are the current recognition of molecules or pollutant detection or explosive detection. But the question is why nano particles. We have like a spear L.C. or Azizi or Kepler electrophoresis these are some traditional techniques that you can use to detect these molecules at a very low concentration but the problem with these techniques are they are very very time consuming and expensive liver intense. So that's why. Nowadays the trend is going on with nano particle based as C. we see is very less expensive less time consuming and sometimes naked eye detection is basically in case of the Roman you can actually detect. What you know discriminate other molecules because the Roman spectrum for a molecule is as I said is kind of a fingerprint of the molecule or and that's why this nano particles based Ses getting very very popular nowadays. OK. Here is some leaders survey that I would like to show you what's going on in terms of glory metric detection or Kyra little mention of molecules or in unseen Mars. So if you have silver nano particles. You can you know be and in those nano particles. If you use L. cysteine you don't see any aggregation no color chains meaning when else is thin binds to the surface of the nanoparticle nothing happens to them aboard. OK but same Sistine but it's the. The Sistine then nano particles aggregate you can actually discriminate. To enhance your Mars by using particles right. As you can see the color changes. So for silver nanoparticle by the way the color is yellow orange and then when it aggregates it becomes kind of brown red is brown kind of color and then if you do send a fuse of that sample you see the nano particles are no longer dispersed they are at the bottom. Forming a pallet at the bottom of this and refuse. To use. So that's one and another technique the use. In all that technique you can actually many pull it on your own based on what kind of monolayer capping you are easing on the surface of the nanoparticle whether gold or silver. So this particular group they have created it's called the lakes or in one of the molecule Hughes organic molecules used for you know for coordinates in chemistry or you know binding metal and but what they're doing the synthesize this molecule putting a softening group in there. By treating the whole thing using So if you guess it. OK So and then the generated nano particles or from the gold sold in presence of this molecule and reducing by sodium will hide it so that they get a molecule of this. OK sulfur needed to live in and this is just the one portion of that. Whole picture as you can see and the negative sores on the soulfully it also binds to the surface on one side and the other side you have some leftover sulfur need groups and they provides the charge on the matter nanoparticles by the way the story is important on the nano particles otherwise they would aggregate So you have to have some molecules kept they are they needs to be charge either positive or negative. Otherwise they would be right and what they are doing we dispose Diggler of system they have. Created. They're trying to look at this type of environmental pollutants like a means fair I mean this is bare and matter and or. So what they have seen if they use para then there is a gate and as you can see the purple color that reproduce sexually it's a gating because these two ants see the surface of the nano particles as negative and these guys are positive right. So so they would electrostatically bind and then there will be a chain formation or maybe in the three dimensionally they will just aggregate together and then. And so you can see that call or email trickily detect or maybe naked eye detection is possible same thing happens with the Mehra group mean. You know aggregation happens. I mean on form chains or in all directions but you would see aggregation in there too but if you have the or to a compound. Eludes us bind to the molecule. But you don't see any aggregates and so you can actually discriminate based on what is their structure right. You can eat can. And this is just one example you can discriminate any type of molecule having different structural. Care. That's one of the techniques and other one is recently another paper in. C.S. years in two thousand and nine they are using a specific or even still glory metric technique do to detect T.N.T. you you're familiar with the name T.N.T. right. Trying to troll when we seize an explosive. So you can actually detect T.N.T. using gold nanoparticle based system. And what they're trying to show in here. The use different derivatives like D.M.T. or it's just a night or a few normal and T.N.T. and then tried to see in you see the maximum aggregate and and they have. Design a nanoparticle system where the captain golden an operative is cysteine and then the Sistine binds to the T.N.T. and forms a complex the called maze in Hammer complex. I did not so that particular structure in here but you can find it in that reference if you would like to. And then when it is bonded to the surface. Now it's the T.N.T. is very close to the surface and when you do a spectrum on there you get a and hand spectrum even for. Very low concentration like in P.P.M. level less than one hundred ppm concentration in can detect T.N.T. so. So this is very useful technique from their perspective. OK What they are sawing the images of the on aggregated goal nanoparticles and when environs to the T. and T. The they do this aggregate OK so you can detect a dead weight and now let's talk about I have been doing as you. So again as I said this is a very new field for me I have worked with some of this effect in molecules before myself and some other molecules synthesizing a nanoparticle system. Most commonly used gold nanoparticles they do synthesize using our sodium citrate we see a reducing is and also a capping Eason. So it works in two ways. So that's the structure of secret on as you can see freak or both the late and one always and you have those negative some charges on there. So off as in binds to the surface of the Nano particle and then the negative surges gives the stability to those nano particles they are well dispersed in water and you can generate different sizes of nano particles based on how much reducing is in you are using in your synthetic procedure. So what I did synthesize these. Following the leader is a procedure and generated a new care. Moloch you are replacing all those secrets by A and mean and. I'm in the bromide OK. I'm going to use they have the name for this now on. And if all these mean. OK what my initial call was that OK. It has been known that some in means actually bind to the gold surface but not covalent lead the way the sulphur does it just binds to the surface using the. And then there was my initial thought that OK. I mean with mine to the surface and then use these C. to who says positively sure it's surface act and will enter does it it would be stale of these I mean. And then give the positive chores. Right but later on it. I end up having and means. Actually in there as a cause or effect and and the seed there forms a by layer kind of thing. So it is known in the literature that seed there does bind nanoparticles surface but not this very cool ones but the rod nano robots arrived. And then arose. So those were known already. So now I when we desist them and first. Lot of see they have in their exist aggregates first and then you add any and str for overnight and you get a nice color coming back the red color comes back. Meaning and then you have to send if used to get rid of leftover any and excess any and see they have to get actually more dispersed and then a particles with positive charges on their Ok so here is the V's data for this particular system that. We have found. So that the first one. A Re presents these citrate kept nanoparticle and then the second one saved a little bit as I have said if something binds to the surface the S.P.R. band sift through the ride if he gets a little larger in size. So that the B. is the red one where I have any and see them together it's a cons of it and now I also look at what happens if I use only see that no any in their right in that situation. I get a kind of blue purple solution. Meaning indicates the aggregation and if you look at the E.V.P. spectrum of that particular system here you see some nano particles are there but you see this this particular area that indicates aggregate formation at around six fifty nanometer here and now also tried to do. OK that's what happens we see there. What happens with any only right. The IN mean only in their case I see a nice red color but this is this is the means by facing All right so you see if a separation. You see the Nano particle at the bottom and another phase of maybe any we see is very organic eating so it kind of forms like an oil thing. So you see is face separation in there and if I do an E.V.A.'s on that system. What I see it's not sifted from the black one right. That means the sit with one that means citrus or stillborn that you know a mean is kind of giving an organic environment around. So this is what happening and Other than that I don't see any aggregation but once I said if you use that system then everything is gone then it's everything is aggregated OK So that kind of convinced me that when I use any and see they have together then it gives is. Stable system. OK And the last one. What I had to make sure that. OK this and see the system is positively sure it's because of the Internet is it it is by a layer of the C.T.M. and I wanted to eat a negatively shirts protein A.C.C. and then see if that protein electrostatically binds to the. To the surface of the positive litters nanoparticles that we have created. So this is the spectrum for the last month the intensity is low. The reason is forty is when I add the A.C.C. and then I need to get rid of those leftover races say on down one. So I had to send if use again. And so some of them are nanoparticles I also get rid of so that's where as you've seen density is low and but as you can see a sift through are to ride size increases as a system binds to the surface outside India less data and some of this is about insulin for me some little bit later. OK. And we also did some F D R on these samples so the bottom one is the F D R forty any of the mean you see these stress these C eight stress in the air means. I mean change right. So I mean has all those see it is you see he used signal for that. And these and eat that signal right here around the area I just had blown up in this area of that particular stress is really weaker than always in water or in Elko All right so any says traditionally weaker So you see a weak signal in there they are there. And what about the CD So this is the this is the stretch for that and the S. and this signal is the banding for the enemies in the area around fifteen and when I do the I.R. for the seat I have only then again I see that signal around this to any nine. Hundred is basically or all those the straights. OK in here. If you can see all so many C.S. is in there in this factor molecule so you can see that. And this is the Strat and this is the bending of the C.S. in this area around fourteen fifteen and now what happens if these two. You know forms the moment of the on the nanoparticle surface. So the top one is the nanoparticle So I see these stress. The CA stress and some kind of banding for the sea there but the race you why is this one is maybe low show you why it is no later is when you Cdn a margarita because there we can do the integration better than in our so I'll tell you why this is weak and again you know I mean is weak here. So we can't see much so to it. I mean up to this I was not convinced that any still there until a do. Did the enum are OK but I think it is there and also you would see those seeds bending in the series and if I blow up their spectrum in it's very noisy dope. All right so now we have created this system where we have the goal call here and. The still reason meaning one thing sell this is hydrophobic tail of any and C. to have it's generating a kind of hydrophobic area in there. OK So water normally doesn't enter so outside blue reason is the water. OK So these are now well more dispersed because of the positive church around due to this positively church group in there. OK And to see that. Now let's talk about some Dynamic Light Scattering size distributions so one can do the size distribution for the secret gap there we created a following the literature method we got to. Any nanometer seated cabinet particles. When I put any and see them in their size increases little bit about three nanometer increase WHO SEES was actually does make sense if we look at that the length of the. If we have two of those into this is dated then probably that length is about three nanometer or thirty ENGSTROM right. And when I put a sissy on top of this conjugate any gate. It is a by the way is the negative which are its protein and size is about fifty five nanometer OK. And as you can see those samples is here this it would be the NE C. and the protein cap the finally came. I mean I did not do anything with the protein later on the reason I wanted to see this negative Beecher's to prove binds. Because. As I have the C.D.R. who says positive. I wanted to see if they negative Beecher's protein binds electrostatically or not so. So this kind of so that it does. Now. M.R. evidence. So I have to do the enum are so this particular spectrum is I'm storing the ranges separately OK this is from point four five ppm to do point two And this is two point five to the rest. OK Same in Amar same sample but I'm just cutting it off on a not suing the whole grains altogether it's easier if I blow up there. OK So that's the spectrum forty in mean OK and the C. one close to the a mean I'm seeing that he won those two Prudence So up here as a triplet OK. And these C. to those up. It's kind of a multiple it here and others from C.T. to see a day so up late. If you use signal right here. OK And for. The metal group at the end it's like it's a triplet but it's not that well resolved though. So you can see those That's forty I mean. And now. Indeed you all by the way all the samples are indeed to the right and the second one is for the seat there. This is the structure again you know this is sewing up right here and see two is in this area and these are C three to see fifteen prom see tree privacy fifteen prime is in this area. OK And. The metal group is right here. OK And what you can see between these two molecules. Structurally dispersant is very similar and then the metal group area. So this reason is very similar for these two molecules. OK it's hard to differentiate you see a little bit of safe to do. In the in the signal but not THAT months. OK. Another difference between these two molecules are forty feet ab we have these three metal groups directly bonded to the nitrogen by the meters night resent those so up as he was signal right here. OK there is not there for these any or right. And you might be wondering where do we see these any. Indeed you. They're going to exchange we did You will see you're going to see. OK so there is the exchange rate is faster than the end of March time scale. That's why you are going to see those two. OK. And the C. one. And the C. one for Lisa I mean they are well separated so these two reasons are really are our key to detect when both of them are together in the nanoparticles surface. OK that's our team and when we have any C.T. have to get or without the nanoparticle these organs one. So then what happens we can distinguish these two are right and but this area kind of very clumsy now. You cannot actually distinct. As they are together. OK. And this is a distinct right because this is from the amine and these two are from the seat that. OK Now when we have the nano particles. I have a different signal right here. I'll talk about that little bit later because it needs some discuss and I probably need some feedback from you guys. So in this system now we have very similar what we see in this area. And as you know is the or this trip at this triplet signal from the any still there in the nano particles ample when these two are. In kind of a mono layer for me on top of the surface of the nano particles right and what we see these signals are not sifted these are not that sifted and these two are almost the same what it is sifting is this particular one. OK. That means coming from these three mantle groups of the sea there and also this see one. Very close to this one resent right and what makes me convinced that. OK The Annie is actually not bonded to the surface because we see no sifting. Because it's electronic and Vironment is not changing. It's. If it is bonded to the metal surface then it will its electronic environment with chains and then you see a saved. Close to that particular night was and right. So this night is in is definitely not beyond it even though it's hanging around as a cause effect and in that one hydrophobic region there. Now what is sifted most as I said this guy from the sea there and then they see one close to the ninety percent right. Those two are dramatically sifted as you can see all right in into an enum are even though it's not three ppm saved but it's dramatic for prudent and lawn care. So now what i also the owls. The deed to be or isn't a nanoparticle with secret in there to see what happens. OK. Just to make sure that as a control. So in this area we have nothing for the secret right. And this is the structure for citrus you will see these two C. is to see is to right and that signal is right here for the C. trail. OK so these two bottom two are the nanoparticle samples and in both cases this is seated one right. If you are seeing a double double it for these two arrived. This is two groups. It's not a regular single double double because of the environment how it is there now the question is in both nanoparticle samples what I see a additional signal. OK And looks like that particular hum. Maybe there is some surface bond the water molecule but I don't know. OK so that's what giving me trouble right now. All right now let's take a look at the system what we have done so to get irregular nanoparticle system with sit with care and then. If I focus on that area. How does it look like look like this those secret groups on the surface of the gold write and what I did replace those sit for it and do it anyway and see they're in there this is how it looks like right. This is how assuming you know this is might your reader probably the any and the CD of sorry kind of Internet is that it. One side is here bonded to the surface of the gold and other side it's providing the sorries so that the nano particles are more dispersed and meanies just hanging around as a. Coarser fact and because this area is highly hydrophobic and I mean it is also hard for me right. Now the reason why I wanted this particular. Picture here or in vision in that this could be the possible. Scenario here. The reason is there is some literature report on gold nano rods where C.D.B. is bonded to the surface. OK And very similar way but in their case you do not need and I mean to stabilize it forty rods see they can stabilize that. OK So that's the reason I am doing it this way. I leave ensued there at the end of the talk now biggest trouble here is these two homes why they are there. I know the water signal appears at four point eight. Even though you do it in the two there are some A So the left over. You see a signal at four point eight those signals are there I have not sown the scaling up there but we have this additional signals and while I am thinking maybe there are some water molecules born that to the goal surface and those guys are maybe away from the bulk water bulk of the two and probably they are not exchanged we did did you some weirdly hide is involved in these reason and death the signal for these for the sea trip gap that's what my Invision right now and same thing we did means we D. other have nanoparticle we have some maybe some water molecules are hiding in this area a way from the bottled water and then those guys are suing are because they are not exchanging with the water right or I mean maybe in case in this case maybe a mean and these guys together sewing up their home. And by the way these two spectra are the know when molecule binds to the Nano particle the concentration on those molecules is very low so we have only a three hundred megahertz instrument at K.S.U. So these were run for twelve hours. OK. Those two span twelve hour and these were just ten minutes. The other spectrum care. So and you know as I said earlier so this is my vision that maybe there are some water molecules. But if you have a better idea just let me know at the end. OK. Now while why did here secret cap and then any seed there right. Then I did a sissy. So it gets bigger right. Ace's it binds electrostatically which is negative and these are some of the size ends it over to unseal or chores information what is the church on the nanoparticle for the regular seated up until about thirty seven and then size is twenty nanometer But again if you look at the picture. It doesn't match do so. I do apologize for that not it's not to scale. But and then. Other ways it's not easy to draw these lengthy molecules and heart tissue in there with care and the. Any seedier Gav nanoparticle if you look at is it a potential which is actually positive number and that corresponds to these and the size is twenty three about three nanometer increase from here. And that makes sense if you look at the chain length of the surf acting molecules and then when I put the ACE is a molecule in there again does it a bit in still comes back to the negative because it is a negative Beecher's protein so it gives the name servers but I'm suing only one layer here. Maybe several layers I don't know exactly. OK I don't have the pics or maybe my probably get some inside in there. So and then size becomes like fifty eight nanometer for us. OK it's because maybe couple of layers of proteins are there so it gets here. And now the question is how do we use this system. OK For Glory metric detection of let's see cyanide molecule that's what. I have in here. There or any I mean I have some other plans for a future but right now we're trying to detect cyanide in solution at very very low concentration if we can do using this particular system. The reason why they do design here because the design we have a positive resource nanoparticle and if we have cyanide who sees. Where when you dissolve the same cyanide in water so scientists need to be serious. So probably you balance all those choices and then you educate right. And you see. A color change in there. So what happens if you have any See there. This is what the spectrum looked like the S.P.R. band and when you add cyanide in there they would just aggregate the blue represents the aggregation and your spectrum is like that. OK So that indicates aggregates and around six fifty then a meter here if I add one hundred milligrams of cyanide in there but that's two months though. Now this is the simple Evey's but if I do it several different concentration of cyanide then how can I saw it. OK so that's what I would so in my next slide. So here is the slide of our I first did the same thing for secret kept I have notes only in here. So for the seated cab nanoparticles from where I stored it. We need to center it this system and then if I add different concentration of cyanide let's say point zero zero one milligram bar. For leader. Hundred milligram parleyed or what happens to the optical density meaning what I did here. The. The optical density here at five sixty over optical density at five twenty. OK So that race you are using it in the Y. axis here. OK And then the X. axis is the different concentrations of cyanide and as you can see as the concentration of some. Increases. So it goes up. But this is kind of flat. You don't see much chains in there up two point one nanometer OK. For the seated cab now particles now. And what you can envision here if you have seated cab nanoparticle it's negatively charged right. And you are heading for the same sign I'd probably put is your money's neutral aiding neutralizing the church on the nanoparticle and cyanide is hanging around in solution. And finally aggregates right now if you have this positively certain system then when I add finite as you can see even four point one milligram par leader. You see the aggregate a little better than the secret system. So one can say that. OK it's not that great system but it's better at least four point one milligram and point one gram of milligram cyanide in Pour a leader. So it's better than the secret system. OK So this is what you can see in this picture that OK cyanide binds to the positively sure is surface and aggregates OK So this is what you can detect color image trickily based on the dispersant in aggregation OK then what I head here. I also try to do are some Roman our source detection on the cyanide because cyanide has a signal on twenty one hundred centimeter in verse. OK the cyanide carbon nitrogen stretching in the Roman but in this is that when I put the cyanide in there. OK I see the aggregate and glory metrically or using E.V.A.'s but we do Roman I didn't get any luck. The reason probably ease. As you can see the surface is right there right. And this is about three nanometer even though Sinai these close to the surface but it. Maybe not in the hot spot remember that raid and the yellow and blue reason. So maybe a sign. Night is not sitting in the hot spot that's why I do not see a very intense signal in the Roman OK. At one hundred ppm level or even a higher concentration. So then I head another system we see is also positively shirts but the difference in here. It's not a serf economical It's called system in hydrochloride. You can purchase from all this or some other company. So this particular system has been first reported in Cam com in two thousand and four and we tried to reproduce the OR system. The reason they did it. They used this system for D.N.A. binding you know D.N.A. is negatively charged so they have created this policy literate system so that you know D.N.A. binds and then use that as a very cool to transfer D.N.A. All right so this is where they started it. So what I wanted to look at OK this is also a poor little research system and can we use it. Similarly for the caloric metric detection of cyanide or source detection of cyanide. So we did that. But we had trouble for a month to synthesize already produce whatever they have reported but finally we figured it out so it Ward and then we use the caloric metric technique here. The same way. This is the X C A cap and then the sit with care and if you look at the color changes. So you get a sense that OK around this reason meaning point one milligram of cyanide. You see a color change in here. OK So these are by the way those plate readers or plate wells you just add some volume of nanoparticles solution and add cyanide different concentration and just take a picture right. So this is what it is this is the secret. This is the CA system so we did not get very good results for the caloric Dex and for these but what we get for the system we get very nice so. Detection probably the reason is this chain link is very small here. So when I add cyanide aggregate read the cyanide on be close to the surface. Probably it's hitting that hot spot. All right. And that's why I get a very nice signal so this particular black one is two point five cyanide right. He use concentration and if I take a stock solution fifty million dollars cyanide the red one. I don't see anything. And from that stock solution if I ed. Fifty ppm today to my nanoparticle solution. I see a signal. It's sifted because you know it's close to the in and political surface so that when the one hundred signal is there for even fifty ppm for the same cyanide and he says I think pretty good and also four hundred ppm we get a better signal it gets and hands. So the service technique works pretty well for for the system. But not the glory metric and that this one to conclude that it's. Simplicity in our preparation and many police and you can simplify even silver nanoparticles are very simple systems in this is very easy even undergraduate students can do it by the way we are undergraduate So all the work here. I'm reporting some of my undergrad students actually a lot of work in here. OK And then you know it's a solution base sensing system nor getting so we try to get you know stay away from organic solvents so less waste. It's easier and then rapid and naked eye detection is possible if you know you see the color genes and quickly without even using any instrument care and then if you have all the leaders nanoparticles other Vandy Z's recent development that I have seen that they can defer and see it. LONG be any versus fragmented D.N.A. if. Fragmented D.N.A. binds to positively certain nano particles then it's not a gated but long D.N.A. binds then you can actually difference in between so that's one of the. Usefulness of positive research nano particles and need a better understanding how to control the surface of architecture. So that you know I can put my molecule of interest in the hot spot so that that's one of my future goals here so that you know get a better source detection of molecules like pollutants scenes or other explosive type on. OK and that I would like to just tank my department here and maybe go of it here for all his support and help. And so my current student called green here then clearly be able in both of them are involved in this particular project and Maricel is working right now on their project and Misaki is working with the silver nanoparticle project currently and some of the funding from the case you chemistry Incentive Fund and then the callers of science in mant. Mentor pretty easy fund. Thank you for your attention. Thank you. And. Yes. Yes. Yeah that's the plan. We have other effects and molecules like M E four and then the car box that on the other side but those where if we use that system then you know the cyanide may not. I'm closer because go both of these negative Beecher's. So that that's my next goal to see OK if I keep changing the chain length then probably where do I get a better source signal that that's a that's a good point. But again even if I don't get a search signal. I mean Kalu reman trickily I can detect. This is one of these happening. If you can see it and take it. Spectroscopy Mr Mann and it's pretty good I guess so. Yes I think that's what we have been actually recently trying to do if we go back here. See this. I mean. You have three protons in there and then if I. I.D.D. Brahman study last week. If I add metals cyanide which is again cyanide you have Carbonite is and is there but it's not. But what happens in that case I don't see any aggregation I mean that means I can't do anything with E.V.A.'s so I did the Roman and metal cyanide actually glow goes very close to the surface it's sitting in the hot spot and then I see very nice or signal but what we're thinking putting some bulky group in here even though positive research but bulky group maybe do a small molecule cannot enter the surface then we can actually you know handle the system OK a few feet small molecule goes to the surface we open gate and if I put a bulky molecule that means we are putting a gate in there so the small molecule cannot enter to the hotspot and so maybe there is just the beginning to think about the selectively but yeah that's what we have so far but we keep thinking OK. Thank you.