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The Applications of Surface Plasmon Resonance Based on Commercial Digital Disks

Permanent Link: http://ufdc.ufl.edu/UFE0044315/00001

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Title: The Applications of Surface Plasmon Resonance Based on Commercial Digital Disks
Physical Description: 1 online resource (39 p.)
Language: english
Creator: Dou, Xuan
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2012

Subjects

Subjects / Keywords: biosensor -- plasmon -- resonance -- thesis
Chemical Engineering -- Dissertations, Academic -- UF
Genre: Chemical Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Surface Plasmon Resonance (SPR), which is the basis of many standard tools to detect the absorption of materials on metal surfaces, provides a powerful principle to many biosensor applications and lab-on-a-chip technology. Here we present various applications of SPR based on commercial digital disks. We could use DVD-R disks to do different RI (Refractive Index) and bio-sensing tests. Moreover, anti-bacterial tests could be fulfilled with the heat generated from the SPR of the DVD disks. With the help of FDTD (Finite Difference Time Domain) simulation, we investigate the whole range of disks including Blue-ray R, DVD-R and CD-R disks. The difference between these disks is the different data track periods: BD-R to 320nm, DVD-R to 740nm and CD-R to 1600nm. The increasing track period has much higher sensitivity to the change of refractive index at disk surface.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Xuan Dou.
Thesis: Thesis (M.S.)--University of Florida, 2012.
Local: Adviser: Jiang, Peng.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2012
System ID: UFE0044315:00001

Permanent Link: http://ufdc.ufl.edu/UFE0044315/00001

Material Information

Title: The Applications of Surface Plasmon Resonance Based on Commercial Digital Disks
Physical Description: 1 online resource (39 p.)
Language: english
Creator: Dou, Xuan
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2012

Subjects

Subjects / Keywords: biosensor -- plasmon -- resonance -- thesis
Chemical Engineering -- Dissertations, Academic -- UF
Genre: Chemical Engineering thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Surface Plasmon Resonance (SPR), which is the basis of many standard tools to detect the absorption of materials on metal surfaces, provides a powerful principle to many biosensor applications and lab-on-a-chip technology. Here we present various applications of SPR based on commercial digital disks. We could use DVD-R disks to do different RI (Refractive Index) and bio-sensing tests. Moreover, anti-bacterial tests could be fulfilled with the heat generated from the SPR of the DVD disks. With the help of FDTD (Finite Difference Time Domain) simulation, we investigate the whole range of disks including Blue-ray R, DVD-R and CD-R disks. The difference between these disks is the different data track periods: BD-R to 320nm, DVD-R to 740nm and CD-R to 1600nm. The increasing track period has much higher sensitivity to the change of refractive index at disk surface.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Xuan Dou.
Thesis: Thesis (M.S.)--University of Florida, 2012.
Local: Adviser: Jiang, Peng.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2012
System ID: UFE0044315:00001


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1 THE APPLICATIONS OF SUR FACE PLASMON RESONANCE BASED ON COMMERCIAL DIGITAL DISKS By XUAN DOU A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF M ASTER OF SCIENCE UNIVERSITY OF FLORIDA 2012

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2 2012 Xuan Dou

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3 T o my family and friends

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4 ACKNOWLEDGMENTS achievements and I would like to give my special thanks to my parents who gave me financial support to continue my study and also, Dr. Jiang, who gave me the opportunity to improve my research skills. Besides, I feel thankful to my other friends as well.

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5 TABLE OF CONTENTS Page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF ABBREVIATIONS ................................ ................................ ............................. 8 ABSTRACT ................................ ................................ ................................ ..................... 9 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 10 Surface Plasmon Resonance ................................ ................................ ................. 10 SPR Bio Sensing ................................ ................................ ................................ .... 10 Antibacterial Tests Based on SPR ................................ ................................ .......... 11 2 BIO SENSOR APPLICATION OF DVD/DVD ................................ .......... 12 Detection Principle ................................ ................................ ................................ .. 12 Bio Sensing ................................ ................................ ................................ ............ 13 Refractive Index Sensing ................................ ................................ ........................ 16 3 PR ................................ .................. 19 Basic Concept of Sterilization ................................ ................................ ................. 19 Fluorescent Test ................................ ................................ ................................ ..... 20 Cult ure Test ................................ ................................ ................................ ............ 23 Simulation ................................ ................................ ................................ ............... 26 4 FDTD SIMULATION OF GRATING STRUCTURES ................................ ............... 29 Principle of FDTD Methods ................................ ................................ ..................... 29 Different Standards for Disks ................................ ................................ .................. 32 Sensitivity of Disks ................................ ................................ ................................ .. 33 5 RELATED PUBLICATIONS ................................ ................................ .................... 36 LIST OF REFERENCES ................................ ................................ ............................... 37 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 39

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6 LIST OF FIGURES Figure page 2 1 SEM image of DVD and DVD R disks ................................ .............................. 12 2 2 Concept graph to show the basic proc ess of bio sensing ................................ 14 2 3 Microfludic device with biosensing function ................................ ...................... 15 2 4 Bio sensing experimental set up ................................ ................................ ...... 15 2 5 Experimental set up for DVD disk and its reflection spectra ............................. 16 2 6 Reflection spectra of RI test for DVD and DVD R ................................ ............. 17 2 7 Sensitivity for SPR shift of DVD and DVD R ................................ ..................... 17 3 1 Microscope image of burning spot ................................ ................................ .... 20 3 2 Fluorescent image of burning spots under different power condition ................ 21 3 3 Fluorescent image of lase scanning ................................ ................................ 21 3 4 Florescent images of sterilization control test ................................ ................... 22 3 5 The culture tests for four different control groups ................................ ............. 24 3 6 Statistical bar of colony numbers for the previous culture test .......................... 25 3 7 Statitical bar of colony numbers for the Spore sterilization test ........................ 25 3 8 Simulation graph of temperature distribution on disk with laser scanning ........ 27 3 9 ........... 28 4 1 Differential equition (right) transform from original Maxwell equition (left) ........ 29 4 2 Simplification from 3D (right) to 2D (left) ................................ ........................... 30 4 3 Simlification of physical parameters in Z axis (right) ................................ ......... 30 4 4 Differential form for simulation ................................ ................................ .......... 31 4 5 Simulation loop ................................ ................................ ................................ 32 4 6 The basic strcture of DVD disk ................................ ................................ ......... 32 4 7 The distribution of data track periodic for different disks ................................ ... 33

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7 4 8 The simulated reflection peak of disks with different track periodicity ............... 34 4 9 The simulated result of reflection spectra peak position ................................ ... 35

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8 LIST OF ABBREVIATION S FDTD Finite Difference Time Domain Method G.F.P Green Fluorescent Protein LSPR Localized Surface Plasmon Resonance RI Refractive I ndex RIU Refractive Index per Unit SP Surface Plasmon SPR Surface Plasmon Resonance

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9 A bstract of T hesis P resented to the G raduate S chool of the U niversity of F lorida in P artial Fulfillment of the Requirements for the Degree of Master of Science THE APPLICATION S OF SURFACE PLASMON RESONANCE BASED ON COMMERCIAL DIGITAL DISKS By X uan D ou May 2012 Chair: Peng Jiang Major: Chemical Engineering Surface Plasmon Resonance (SPR), which is the basis of many standard tools to detect th e abso rption of materials on metal surface s provides a powerful principle to many biosensor applications and lab on a chip technology. Here we present various applications of SPR based on commercial digital disks. We could use DVD R disk s to do different RI (Re fractive Index) and bio sensing test s Moreover, anti bacterial test s could be fulfilled with the heat generated from the SPR of the DVD disks. With the help of FDTD (Finite Difference Time Domain) simulation, we investigate the whole range of disk s includ ing Blue ray R, DVD R and CD R disk s The difference between these disks is the different data track period s : BD R to 320nm, DVD R to 740nm and CD R to 1600nm. The increasing track period has much higher sensitivity to the change of refractive index at dis k surface

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10 CHAPTER 1 INTRODUCTION Surface Plasmon Resonance, also called SPR is a hot spot in the research area related with bio sensor s wave guide materials, anti bacterial test s and etc. In this thesis, we mainly focus on the topics of bio se nsor and anti bacterial test s Our group has already had several achievements in this area. Surface Plasmon Resonance Surface P lasmon resonance (SPR) can be described as the resonant, collective oscillation of valence electrons in a solid stimulated by inc ident light. The resonance condition is established when the frequency of light photons matches the natural frequency of surface electrons oscillating against the restoring force of positive nuclei. Surface Plasmon (SP) is electromagnetic wave that propaga te s along a metal/dielectric interface and can be pictured as a traveling charge density wave on the surface of a metal. [1,2] The coupling of incident light with free electrons in metal forms Surface Plasmon waves that are essentially confined at the metal dielectric interface, leading to a strong concentration of an electromagnetic field. [3,4] This localized field enhancement has been widely utilized to achieve high ly sensitive chem ical and biological sensing by Surface P lasmon R esonance [3,5] Besides, the strong SPR absorption of incident light could also result in high local temperature, which provides a potential antibacterial application. SPR B io S ensing Surface P lasmon reso nance (SPR) is the key surface P lasmon (SP) technique that could ultimately enab le single molecule level chemical and biological sensors. [6 14]

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11 Due to tremendous recent advances in solution based synthetic methodologies, a large variety of p lasmonic nanoparticles with complex shapes (e.g., spheres, rods, and prisms) have been extensiv ely explored for SPR and SERS sensing. [7,15] The L ocalized S urface P lasmon R esonance (LSPR) around plasmonic nanoparticles enables very high SPR sensitivity. For instance, surface immobilized core shell spherical silica Au nanoparticles [ 16] and rice shape d hematite Au nanoparticles [ 17] have been shown to exhibit bulk SPR sensitivity of 555 nm per refractive index unit (nm/RIU) and 800 nm/RIU, respectively. To resolve the reproducibility issue of stochastically aggregated plasmonic nanoparticles in SERS a nd SPR sensing, various periodic plasmonic nanostructures created by both top down (e.g., electron beam lithography) [13] a nd bottom up approaches (e.g., N ano sphere lithography or NSL ) [18,19] have been widely exploited to achieve reproducible enhancing o f electromagnetic (EM) fields. [7,13,20,21] The SPR sensitivity of these nanofabricated periodic substrates is usually lower than that of plasmonic nanoparticle aggregates. For example, NSL enabled periodic Au or Ag nanoparticles exhibit typical SPR sensiti vity of 200 nm/RIU. [18,19] Antibacterial Test s B ased on SPR The strong SPR absorption of incident light could also result in high local temperature, which has been extensively exploited in hyper thermal cancer treatme nt and antimicrobial coatings. [22] For instance, wet sy nthesized metal nanoparticles [23 25] colloid template gold (or silver) Nano shells [22 26] and periodic gold Nano grail arrays [27] have shown good antibacterial performance.

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12 CHAPTER 2 BIO SENSOR APPLICATION O F D V D/ DVD SPR Detection Pri nciple As introduced before SPR is quite sensitive to the dielectric constant at the surface, in other word s it is the refractive index near the surface which matters We could just use the change of the surface RI to achieve the sensing test. Because of that we have two ways to do the sensing one is bio sensing test, which we use anti gen and anti body; the other is RI test, we use different solutions with their own refractive index parameters. W e use the nanostructured substrate instead of the Pris m cou pled SPR excitation set up. Th e most obvious strengthen point is its smaller size which makes it more portable. And the reason why we use DVD/DVD R commercial disks is that DVD disk has periodic grating structure and we could use that directly. Figure 2 1 is the SEM image of (a) DVD and (b) DVD R disks: Figure 2 1 SEM image of DVD and DVD R disks Reprint with permission from Dou, X.; Chung, P. Y.; Dai, J. L.; Jiang, P.* Surface Plasmon Resonance and Surface Enhanced Raman Scattering Sensing Enabled by Digital Versatile Discs. Ap plied Physcis Letter. 2012, 100, 041116

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13 DVD R consists many data tracks and each tracks has a periodic distance of 740nm. However, DVD disk cont ains the information but not a blank data disk a s DVD R, DVD disk has some differen t pits along the track line. Bio S ensing Bio sensor is an analytical device for the detection of an analytics that combine s a biological componen t with a physicochemical detector component. Bio sensor has a history of its own since last century. In old days, those workers who wor k in the mines underground use a specific bird called Serinus canaria which is more sensitive to the gas leak than human beings. This kind of birds is utilized as a sensor to detect the gas lea k underground. Generally speaking, bio sensor is made by three important parts: 1 ) sensitive biological element; 2 ) transducer or detector elements; 3) reader device. Although the general principle is the same, there have already been many different kinds of bio sensors based on different principles : Photometric, Electrochemical, Ion Channel Switch and etc. Moreover, there are a lot of commerc ialized bio sensors which have been widely applied on the market right now. The most common one should be the blood glucose bio sensor. Some big companies also have the experience in bio sensor manufacture for many years, such as OMRON and Beckman Coulter. For our bio sensor, we use Surface Plasmon Resonance to achieve the target, which belongs to the photometric metho d. As mentioned before, SPR is quite sensitive to the change of refractive index at the surface; we detect the signal change correspond ing to the RI change.

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14 Combined with microfluidic device, our group could also achieve the real time bio sensing. A nd comp ared with other commercial product, the microfluidic SPR detector could make the experiment set up quite smaller and easier Figure 2 2 is the illustrated picture for the bio sensing principle we used. Figure 2 2 Concept graph to show the basic proces s of b io sensing The Figure 2 2 is our nano structured substrate with gold coated surface. Th e reason why it is the gold is that gold surface could bi nd with the Anti BSA, a protein; we inject the solution of Anti BSA thro ugh microfluidic channel in Figure 2 2 ; later on, we continue to add BSA solution, BSA could also bind to Anti BSA. In those following process es different bio materials could change the refractive index continuously. Then, we could detect the change of reflection or transmission spectra In order to further develop the ability of sensor, we combine the microfluidic device and SPR configuration together, so that we could do the real time bio sensing And Figure 2 3 shows the configurati on of microfluidic device :

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15 Figure 2 3 Microfludic device with biosensing function Nanostructured substrate stick s onto the glass with glue and they will be covered by the PDMS mold with microfluidic channel. Figure 2 4 is the whole configration of SPR detector: Figure 2 4 Bio sensing experimental set up

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16 T he light come s from top to bottom, the microfludic device is fixed on the objective stage, and spectrometer coll ects information (transmission mode ). Refractive Index Sensing Similar to the bio sensing, RI test s also focus on the change of refractive index at the surface. However, the differen ce to the bio sensing is that RI test s use different concentration solution s to make the change of RI instead of different bio materials. The objective of using RI test is to get more accurate sensitivity of the s ensor, because bio material will bind on the surface, which would generate a non uniform RI dispersion, so it is necessary to use an uniform RI distribution solution to get standard sensitivity. Besides, the information of those standard solution s makes it easier to simulate sensor s sensitivity. And Figure 2 5 is the (a) RI test experimental set up and (b) related sensiti vity for the DVD R disk. Different with bio sensing, RI test use s static RI solution, so it does not need microfluidic device. (a) (b) Figure 2 5 Experimental set up for DVD disk and its reflection spectra

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17 (a) (b) Figure 2 6 Reflection spectra of RI test for DVD and DVD R (a) (b) Figure 2 7 S ensitivity for SPR shift of DVD and DVD R From the Figure 2 7 we could see that the spectra will have a red shift due to the increasing RI of solut ions. And we get the peak shift to the change of RI, plot it and get slope which is the sensitivity of DVD/DVD R disks. The (a) DVD has a sensitivity of 645nm/RIU (RIU stands for refractive index per RIU), and (b) DVD R disk has a

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18 sensitivity of 848 nm/RIU DVD/DVD R reach a compar a tive high sensitivity to those other nanostrucutre d substrate s till now.

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19 CHAPTER 3 STERILIZATION APPLIC Basic C oncept of Sterilization Here we demonstrate a creative method to kill the bacteria using Surface P lasmon Resonance of DVD disk. I f there is SPR generated on the surface, it could generate the heat simultaneously And we could use the high temperature generated from SPR to kill bacterial on the disk surface. F or the experiment, we use 785nm laser as e xcitation source to generate SPR of disk. A lso, E.coli and Spores are picked up for the further killing test s Ot her different substrates are prepared to further prove the capability of sterilization efficiency of our DVD disks. Before we do the a nti bact erial test, we also ma ke some preparation s for the experiment. The reason why we use DVD disk instead of other substrates is because DVD disk has a n exact resonance peak at position of 785 nm that is to say : the disk will get the strongest resonance when a 785nm laser shot on its surface. Figure 3 1 is a general burning image of 785nm laser with 100% power under 50X objective lens From below image, we could clearly observe the black spot as a burning spot. A nd disk is cover ed with yeast cells. However, w e need another way to easily observe the contrast between the dead cells and cells alive. And we do not want to damage the substrate. That is why we turn to fluorescent test. Reprint with permission from Dou, X.; Chung, P. Y.; Dai, J. L.*; Jiang, P.* Surface Plasmon Resonance Enabled Antibacterial Digital Versatile Disc s. Applied Physcis Letter 2012, 100, 063702.

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20 Figure 3 1 M i croscope image of burning spot Fluorescent Test The reason wh y we use fluorescent test is that it could provide a better contrast than ordinary microscope image. Because it is hard for us to make a judgment that if the cells are eliminated effectively. We use G.F.P E.coli (G.F.P stands for green fluorescent protein) for sterilization test to better detect the living rate of bacterial If we kill the bacterial, the green fluorescent protein would de nature and the green color will vanish. This provides a way to make detection Besides that, we also ma k e other few atte mpts to see the relation s, such as: power of the lase r vs burning efficiency and illumination time vs burning efficiency. Figure 3 2 shows the test based on different power conditions and illumination time. The green background is the G.F.P E.coli. The whi te spot is due to de nature of the G.F.P with such a high temperature from SPR of disk. T he higher power laser has,

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21 the more efficient sterilization would be. And if we shot the laser for a much longer time, it will also increase the sterilization efficien cy. Figure 3 2. Fluorescent image of burning spots under different power condition And we do not just stop at the point burning. Our final target is l arge scale application. We try line scan ning on the disk and g e t very good result. Figure 3 3 Flu orescent image of lase scanning

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22 F rom Figure 3 3 we could see the line scan is very efficient and it is better to scan in X axis direction instead of Y direction. B ecause the shape of laser spot has larger X axis dimension than Y axis. It support s us to do a whole scanning on the disk surface. W e prepare 6 disks for scanning, each three disks for one group. We first spread the G.F.P E.coli on disk surface, and then use the laser to scan the first group and use the second group without laser scanning as cont rol group. Figure 3 4 shows the difference between the substrate s with scanning and without scanning: Figure 3 4 Florescent images of sterilization control test

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23 Figure 3 4 shows that it is quite obvious between the sample s without scanning (1; laser ) and samples after scanning (2,3,4; laser+). After scanning, the substrate s become much darker. This indicates that G.F.P does have a process of de naturing and we need a further test to prove if it kill s the baterial or not And it is a simple relation i f we kill the bacterial, the protein in the bacterial will de nature. T here is no doubt about this. H owever, there is still the possibility for the second circumstance: the G.F.P protein will denature, but the some bacterial is still alive Based on thi s p otential problem, we propose the method of cult ure testing to prove the efficiency of sterilization of SPR. Culture Test Culture test is the basic experiment to prove if the bacterial is a live or not even after the process of burning by disk s SPR. First, we still use the previo u s method to take the test. After we finish the scanning, use the PBS solution to wash the resident material into solution. After that, spread those solution onto different petri dishes with agar inside Then, p ut those pet ri dishes into oven of 50 d e gree for one day culture. A nd there will be some bacteria colonies grow ing from We could just count the number of those colony groups for comparison. Figure 3 5 are the picture s of the four compare d colony groups cultured for a day Here we use four different control group s : a ) Al coverd silicon wafer; b ) Pure DVD disk without metal cover; c ) and d ) are ordinary DVD disks. The first group could tell us if the reason of killing bacterial belongs to the grating structure, and that is why we use the silicon wafer as substrate. The wafer has a polished smooth surface. The second group want to show that it is the metal surface generat ing the SPR, without that, SPR is

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24 impossible. A nd ( c ), ( d ) group just show the diff erence between laser scanning and no scanning. (a) (b) (c) (d) Figure 3 5 The culture tests for four different control groups From the above picture s we could clearly see that ( a ), ( b ) and ( c ) group d o not have a very good steri lization effect. However, the ( d ) group do have a highly effective killing rate. And the data of statistic bar s for these four groups might be more straightforward Compare d with o ther three groups (Control, DVD Al and Si), DVD group d oes have the smallest culture colony groups than other three.

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25 Figure 3 6 Statistical bar of colony numbers for the previous culture test For the bacteral sterilization test, we also make an atte mpt of spore killing in order to see the capability of our sterilization test. Just as the same experimental protocol we did before, we just spread the spores on the surface and do the killing test. Figure 3 7 is the statistic bar s for the spore sterilizat ion: Figure 3 7 Statitical bar of colony numbers for the Spore sterilization test

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26 From the graph we could see that even for the spore, the DVD substrate could have an effective sterilization rate. Using boiling water to kill the spore even takes more than half hour. However, we coul d simply scan the substrate and this will not take a second. In order to better instruct our experiment, we also do some simulation s to provide explaination for the burning efficiency and the estimation of the surface temper ature distribution Simulation Simulation could better instruct us to explain the experiment. And also it is hard to detect the exact temperature on the disk surface, since the laser spot on the surface is tiny and we could not use the ordinary equipment, such as thermometer Under this circumstance, simulation s do give us an understanding of burning mechanism. In order to get a better result, we ignore some complex factors and simplify the model as follows: 1. T ake the area of disk surface into considerati on, the thickness of the disk could be ignored. Use 2D structure instead of 3D 2. Do not consider the grating structure. Instead, we calculate the percentage of absorption of the light to substitute the grating surface by the plain surface. Based on those reasonable proposal s we used COMSOL software to establish the model and got the temperature distribution on the surface. T he center has the diameter of 200 micro meter circle as the size of the laser spot. The disk is illuminated by 100% laser pow er with 30% power absoroption based on reflection spectra. The temperature bar on the right could clearly indicate the temperature distribution on the disk. The highest temperature at the center is 442K

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27 (almost 170 degree). T his temperature could burn the polycarbonate beneth aluminm surface. Figure 3 8 Simulation graph of temperature distribution on disk with laser scanning A series of simulations has been taken of different power percentage at 75%, 50% and 25%. A nd there is a linear relationship betw een different laser power and disk s highest surface temperature. It also explain s why we could not see any burning signs below the 50% power Figure 3 9 shows that, at 25% laser power, the disk s surface temperature only reaches 330K (almost 60 degree), a nd this temperature is lower than the melting point of polycarbonate substrate. 50% laser power still has a temperature of 100 degree to burn the disk substrate. And those similation results match well with experimental result s

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28 Figure 3 9 Simulation of relation between the laser power and disk s temperature

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29 CHAPTER 4 FDTD SIMULATION OF GRATIN G STRUCTURES Principle of FDTD M ethods FDTD method stands for Finite Difference Time Domain method. This is a basic method to solve the electric field distribu tion in the electromagnetic field. T his method was first introduced by K. S. Yee s Numerical solution of initial boundary value problems involving Maxwell s equations in isotropic media in 1966 T his numerical method derives from the Maxwell equat ion. Differentiate the equation on time and space. Grid the space and do the circulation calculation to get a final convergent solution from a single point to the whole electrical magnetic field. And this section would introduce how this method works. Maxw ell equation simplification show as Figure 4 1 : Figure 4 1 Differential equition (right) transform from original Maxwell equition (left)

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30 Transfer the Maxwell equation from classic form into differential form. A nd we here just discuss 2D form. Figure 4 2 Simplification from 3D (right) to 2D (left) Further simplification of the differentiate equation based on 2D structure: all the phycial parameter with note zero Then we get simplified form from left to right. Figure 4 3 Simlification of phys ical parameters in Z axis (right)

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31 From the two sets of equation s on the left side, we pick up the second set for our later explaination. The magnetic field is vertical to eletrical field. So, if the electrical field in Z direction is zero, the magnetic fie ld in the direction which is vertical to Z should also be zero: that is X and Y direction. Figure 4 4 Differential form for simulation Finally, we got the form of finite difference on space and time domain shown as Figure 4 4

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32 Figure 4 5 Simul ation loop Figure 4 5 is the loop of the simulation. We propose the parameter at t=n and t=n 1/2; we could get magnetic distribution of t=n+1/2 from a and b; following that, electric distribution at t=n+1/2 is known. Then substitute value f ro m second and thi r d step into a and b equation, we could get true value of t=n and t=n 1/2 time step. We continue this round till we get convergent value at time step t=n and t=n 1/2. Different S tandards for D isks Besides those experiments related with DVD disk, we also investigate the relationship between those different commercial disks, including BD R, DVD R and CD R. The difference between those three disks is their data track period s Figure 4 6 is a basic illustrated structure of DVD disks: Figure 4 6 The basic strcture of DVD disk

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33 In the Figure 4 6 above, we could see that the 740nm is the track period. And those dots contain the data information. That information is stored along those spiral lines on the disk surface. There are some standard s for DVD dis ks parameter, such as its periodicity its pits width, height and etc. We pick up the BD R, DVD R and CD R for the FDTD simulation and also choose several midpoints of track periods among three standard disks as continuous research. For example, we pick u p two points between BD R and DVD R, and three points between DVD R and CD R, as the Figure 4 7 shown below. Figure 4 7 The distribution of data track periodic for different disks BD R has a period of 320nm, DVD R has a period of 740nm and CD R has 160 0nm. Sensitivity of D isks For the FDTD simulation, we mainly focus on its sensitivity of SPR peaks shift. We mainly simulate the reflection spectra of those disk s under different refractive index environm ent and compare the results of BD R, DVD R and CD R with their experim ental result s to judge simulation accuracy.

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34 Figure 4 8 is the reflection spetra of different disks in the RI environment of 1.33: Figure 4 8 The simulated reflection peak of disks with different track periodicity The bar in the grap h indicates different disks with their own periodic track distance. W e could cearly observe the relationship between the peak position and track distance: with the increasing track periodic distance, the pe ak position would have a re d shift to longer wavel ength. And for the experiment, our lab do not have such a spectrometer to detect such a long wavelegnth beyond the 1200nm. We have to find another way. A nd for the sensitivity, we also have an interesting result: T he sensitivity increases with the the incr easing period ic track distance. And Figure 4 9 below clearly discribe that relation:

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35 Figure 4 9 The simulated result of reflection spectra peak position The wavelength is the data track distance. The blue line indicate the sensitivity of the surface p lasmon resonance. A nd black on e indicates the peak position. Especially for the CD R disk, it reached the highest sensitivity at 16 00nm/RIU. That might be the highest sensitivity at present And the highest sensitivity in the current literature is around 8 00 nm/RIU. If CD R could truly reach such a high sensitivity, it would almost double the record. That would be another exciting point we need to prove

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36 CHAPTER 5 RELATED PUBLICATIONS The work in the thesis paper has been published in the scientific journal (Applied Physics Letter). C Surface Plasmon Resonance and Surface Enhanced Raman Scattering Sensing Enabled by Digital Versatile Discs Surface Plasmon Resonance Enabled Antibacterial Digital Versat ile Discs. Besides, the project related with anti bacterial test has been applied as patent DVD disk enables bacterial sterilization and sensitive bio sensing to the Journal and original authors. And they are provided on the Applied Physics Letter. If you have interests on our technology, please contact UF Office of Technology or original authors.

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37 LIST OF REFERENCES 1. E. Ozbay, Science 311, 189 (2006). 2. W. L. Barn es, A. Dereux, and T. W. Ebbesen, Nature 424, 824 (2003). 3. J. Homola, Chem. Rev. 108, 462 (2008). 4. H. Wang, D. W. Brandl, P. Nordlander, and N. J. Halas, Acc. Chem. Res. 40, 53 (2007). 5. M. E. Stewart, C. R. Anderton, L. B. Thompson, J. Maria, S. K. Gray, J.A. Rogers, and R. G. Nuzzo, Chem. Rev. 108, 494 (2008). 6. S. M. Nie and S. R. Emery, Science 275, 1102 (1997). 7. M. E. Stewart, C. R. Anderton, L. B. Thompson, J. Maria, S. K. Gray, J. A. Rogers, and R. G. Nuzzo, Chem. Rev. 108, 494 (2008). 8. J. Homola, Chem. Rev. 108, 462 (2008). 9. E. C. Le Ru and P. G. Etchegoin, Principles of Surface Enhanced Raman Spectroscopy and Related Plasmonic Effects (Elsevier, Amsterdam, 2009). 10. H. Wang, D. W. Brandl, P. Nordlander, and N. J. Halas, Acc. Chem. Res. 40, 53 (2007). 11. W. A. Murr ay and W. L. Barnes, Adv. Mater. 19, 3771 (2007). 12. W. L. Barnes, A. Dereux, and T. W. Ebbesen, Nature 424, 824 (2003). 13. C. Genet and T. W. Ebbesen, Nature 445, 39 (2007). 14. K. Kneipp, H. Kneipp, and J. Kneipp, Acc. Chem. Res. 39, 443 (2006). 15. C. Loo, A. Lin, L. Hirsch, M. H. Lee, J. Barton, N. J. Halas, J. West, and R. Drezek, Technol. Cancer Res. Treat. 3, 33 (2004). 16. F. Tam, C. Moran, and N. J. Halas, J. Phys. Chem. B 108, 17290 (2004). 17. J. A. Dieringer, A. D. McFarland, N. C. Shah, D. A. Stuart, A. V. Whitney, C. R. Yonzon, M. A. Young, X. Y. Zhang, and R. P. Van Duyne, Faraday Discuss. 132, 9 (2006). 18. C. L. Haynes and R. P. Van Duyne, J. Phys. Chem. B 105, 5599 (2001).

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38 19. P. M. Tessier, O. D. Velev, A. T. Kalambur, J. F. Rabolt, A. M. Lenhoff, and E. W. Kaler, J. A m. Chem. Soc. 122, 9554 (2000). 20. S. G. Jang, D. G. Choi, C. J. Heo, S. Y. Lee, and S. M. Yang, Adv. Mater. 20, 4862 (2008). 21. M. M. Varma, H. D. Inerowicz, F. E. Regnier, and D. D. Nolte, Biosens.Bioelectron. 19, 1371 (2004). 22. M. M. Varma, D. D. Nolte, H. D. I nerowicz, and F. E. Regnier, Opt. Lett. 29, 950 (2004). 23. C. Loo, A. Lin, L. Hirsch, M. H. Lee, J. Barton, N. J. Halas, J. West, and R. Drezek, Technol. Cancer Res. Treat. 3, 33 (2004). 24. G. Fuertes, O. L. Sanchez Munoz, E. Pedrueza, K. Abderrafi, J. Salgado, and E. Jimenez, Langmuir 27, 2826 (2011). 25. Kumar, P. K. Vemula, P. M. Ajayan, and G. John, Nature Mater. 7, 236 (2008). 26. Marambio Jones and E. M. V. Hoek, J. Nanopart. Res. 12, 1531 (2010). 27. R. Bardhan, S. Lal, A. Joshi, and N. J. Halas, Acc. Chem. Res. 44, 9 36 (2011). 28. Dou, X.; Chung, P. Y.; Dai, J. L.; Jiang, P.* Surface Plasmon Resonance and Surface Enhanced Raman Scattering Sensing Enabled by Digital Versatile Discs. Applied Physics Letter. 2012, 100, 041116. 29. Dou, X.; Chung, P. Y.; Dai, J. L.*; Jiang, P.* S urface Plasmon Resonance Enabled Antibacterial Digital Versatile Discs. Applied Physics Letter. 2012, 100, 063702.

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39 BIOGRAPHICAL SKETCH Xuan Dou received his B.S. degree of mechanical engineering from University of Science and Technology of China in 2 010. He then joined the Department of Chemical Engineering at University of Florida. He mainly focuses on the application of s urface p lasmon r esonance based on different Nano structured substrate s He will get his Master of Science deg ree in 2012 and conti nue h is Ph.D. study in material s cience s at Northwestern University.