Biomod/2014/wiki-2'.html

From OpenWetWare
Revision as of 03:37, 27 August 2014 by Jin Tiansheng (talk | contribs)
Jump to navigationJump to search

<html> <head>

<meta content="text/html; charset=gb2312" http-equiv="Content-Type"> <script language="JavaScript"> <!-- function MM_showHideLayers() { //v9.0 

 var i,p,v,obj,args=MM_showHideLayers.arguments;
 for (i=0; i<(args.length-2); i+=3) 
 with (document) if (getElementById && ((obj=getElementById(args[i]))!=null)) { v=args[i+2];
   if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v=='hide')?'hidden':v; }
   obj.visibility=v; }

}

function MM_preloadImages() { //v3.0 

 var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
   var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
   if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}

} function MM_swapImgRestore() { //v3.0 

 var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;

} function MM_findObj(n, d) { //v4.01 

 var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
   d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
 if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
 for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
 if(!x && d.getElementById) x=d.getElementById(n); return x;

}

function MM_swapImage() { //v3.0 

 var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
  if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}

} //--> </script>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>无标题文档</title> <style type="text/css"> .ys01 { font-size: 90px; color: #BABABA; text-align: left; } .ys02 { font-weight: bold; font-family: "Trajan Pro"; font-size: 36px; color: #999; text-align: left; } .ys3 { color: #000; font-weight: bold; } .ys03 { color: #C60; } .ys04 { color: #C90; } body { background-color: #F3F9F1; }

  1. apDiv1 {

position:absolute; left:50px; top:250px; width:240px; height:200px; z-index:1; }

  1. apDiv2 {

position:absolute; left:300px; top:7957px; width:450px; height:30px; z-index:2; }

  1. apDiv3 {

position:absolute; left:697px; top:296px; width:267px; height:51px; z-index:3; }

  1. apDiv4 {

position:absolute; left:950px; top:500px; width:230px; height:98px; z-index:4; }

  1. apDiv5 {

position:absolute; left:600px; top:20px; width:450px; height:150px; z-index:5; background-image: url(bj2.jpg); }

  1. cd1 {

position:absolute; left:140px; top:230px; width:110px; height:120px; z-index:6; visibility: hidden; }

  1. bt table .ys04 td {

font-size: 24px; }

  1. cd1 table tr td {

font-size: 18px; }

  1. cd2 {

position:absolute; left:268px; top:230px; width:150px; height:120px; z-index:7; visibility: hidden; }

  1. apDiv6 table tr td {

font-size: 18px; }

  1. apDiv6 table tr td {

font-weight: bold; }

  1. cd2 table {

font-size: 18px; font-weight: bold; } a:link { color: #789262; text-decoration: underline; } a:hover { background-color: #CFF; } .bt1 { font-family: "Trajan Pro"; font-size: 18px; font-weight: bold; background-color: #7BCFA6; color: #789262; } .bq1 { font-family: Arial, Helvetica, sans-serif; font-size: 18px; font-weight: bolder; color: #A98175; } .bq2 { font-size: 18px; font-family: Arial, Helvetica, sans-serif; font-weight: bolder; } .bq3 { font-family: "Arial Black", Gadget, sans-serif; font-size: 24px; color: #789262; }

  1. apDiv8 {

position:absolute; left:900px; top:8940px; width:90px; height:80px; z-index:8; } .js { font-family: Arial, Helvetica, sans-serif; font-size: 22px; color: #41555D; font-weight: 200; } a:visited { color: #789262; }

  1. apDiv9 {

position:absolute; left:300px; top:275px; width:370px; height:30px; z-index:9; }

  1. apDiv10 {

position:absolute; left:300px; top:320px; width:750px; height:70px; z-index:10; }

  1. apDiv11 {

position:absolute; left:300px; top:1190px; width:260px; height:50px; z-index:11; }

  1. apDiv12 {

position:absolute; left:300px; top:1262px; width:750px; height:20px; z-index:12; }

  1. apDiv13 {

position:absolute; left:300px; top:8190px; width:750px; height:80px; z-index:13; visibility: visible; }

  1. apDiv14 {

position:absolute; left:300px; top:9090px; width:660px; height:60px; z-index:14; text-align: center; }

  1. apDiv15 {

position:absolute; left:610px; top:3982px; width:200px; height:110px; z-index:15; }

  1. apDiv16 {

position:absolute; left:300px; top:4550px; width:750px; height:131px; z-index:16; }

  1. apDiv17 {

position:absolute; left:300px; top:4210px; width:320px; height:60px; z-index:17; }

  1. apDiv18 {

position:absolute; left:670px; top:4210px; width:320px; height:180px; z-index:18; } </style> <script src="Scripts/swfobject_modified.js" type="text/javascript"></script> <script src="Scripts/AC_RunActiveContent.js" type="text/javascript"></script> </head>

<body onLoad="MM_preloadImages('20090115201834758.jpg')">

<div id="apDiv7" style="position: absolute; left: 50px; top: 20px; width: 550px; height: 150px; z-index: 3; vertical-align: middle; font-weight: bold; background-image: url(bj1.jpg); layer-background-image: url(bj1.jpg); border: 1px none #000000;"> 

 <object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="550" height="150" hspace="0" vspace="0" align="top" id="FlashID2">
   <param name="movie" value="粉色流苏鼠标跟踪.swf" />
   <param name="quality" value="high" />
   <param name="wmode" value="transparent" />
   <param name="swfversion" value="8.0.35.0" />
   <!-- 此 param 标签提示使用 Flash Player 6.0 r65 和更高版本的用户下载最新版本的 Flash Player。如果您不想让用户看到该提示，请将其删除。 -->
   <param name="expressinstall" value="Scripts/expressInstall.swf" />
   <!-- 下一个对象标签用于非 IE 浏览器。所以使用 IECC 将其从 IE 隐藏。 -->
   <!--[if !IE]>-->
   <object data="粉色流苏鼠标跟踪.swf" type="application/x-shockwave-flash" width="550" height="150" hspace="0" vspace="0" align="top">
     <!--<![endif]-->
     <param name="quality" value="high" />
     <param name="wmode" value="transparent" />
     <param name="swfversion" value="8.0.35.0" />
     <param name="expressinstall" value="Scripts/expressInstall.swf" />
     <!-- 浏览器将以下替代内容显示给使用 Flash Player 6.0 和更低版本的用户。 -->
     <div>
       <h4>此页面上的内容需要较新版本的 Adobe Flash Player。</h4>
       <p><a href="http://www.adobe.com/go/getflashplayer"><img src="http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif" alt="获取 Adobe Flash Player" width="112" height="33" /></a></p>
     </div>
     <!--[if !IE]>-->
   </object>
   <!--<![endif]-->
 </object>

</div> <div id="apDiv5"> 

 <object id="FlashID" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="150" height="150">
   <param name="movie" value="~光晕.swf">
   <param name="quality" value="high">
   <param name="wmode" value="transparent">
   <param name="swfversion" value="8.0.35.0">
   <!-- 此 param 标签提示使用 Flash Player 6.0 r65 和更高版本的用户下载最新版本的 Flash Player。如果您不想让用户看到该提示，请将其删除。 -->
   <param name="expressinstall" value="Scripts/expressInstall.swf">
   <!-- 下一个对象标签用于非 IE 浏览器。所以使用 IECC 将其从 IE 隐藏。 -->
   <!--[if !IE]>-->
   <object type="application/x-shockwave-flash" data="~光晕.swf" width="150" height="150">
     <!--<![endif]-->
     <param name="quality" value="high">
     <param name="wmode" value="transparent">
     <param name="swfversion" value="8.0.35.0">
     <param name="expressinstall" value="Scripts/expressInstall.swf">
     <!-- 浏览器将以下替代内容显示给使用 Flash Player 6.0 和更低版本的用户。 -->
     <div>
       <h4>此页面上的内容需要较新版本的 Adobe Flash Player。</h4>
       <p><a href="http://www.adobe.com/go/getflashplayer"><img src="http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif" alt="获取 Adobe Flash Player" width="112" height="33" /></a></p>
     </div>
     <!--[if !IE]>-->
   </object>
   <!--<![endif]-->
 </object>

</div> <div id="cd1" onMouseOver="MM_showHideLayers('cd1','','show')" onMouseOut="MM_showHideLayers('cd1','','hide')"> 

 <table width="100%" border="2" cellpadding="2" cellspacing="2" class="bq1">
   <tr>
     <td align="center"><p><strong>DESIGN</strong></p></td>
   </tr>
   <tr>
     <td align="center"><p><strong>ABSTRACT</strong></p></td>
   </tr>
   <tr>
     <td align="center"><p><strong>GOAL</strong></p></td>
   </tr>
   <tr>
     <td>&nbsp;</td>
   </tr>
 </table>

</div> <div id="cd2" onMouseOver="MM_showHideLayers('cd2','','show')" onMouseOut="MM_showHideLayers('cd2','','hide')"> 

 <table width="100%" border="2" cellpadding="2" cellspacing="2" class="bq1">
   <tr>
     <td align="center"><p>MATERIALS</p></td>
   </tr>
   <tr>
     <td align="center"><p>METHODS</p></td>
   </tr>
   <tr>
     <td align="center"><p>DISCUSSION</p></td>
   </tr>
   <tr>
     <td align="center"><p>&nbsp;</p></td>
   </tr>
 </table>

</div> <div id="apDiv1"> 

 <table width="234" border="2" cellspacing="2">
   <tr>
     <th class="bq2" scope="row">PROJECT</th>
   </tr>
 </table>
 <table width="200" border="2" cellpadding="2" cellspacing="2" class="bq1">
   <tr>
     <td align="left"><a href="#motivation">※MOTIVATION</a></td>
   </tr>
   <tr>
     <td align="left"><a href="#design">※DESIGN</a><a href="#abstract"></a></td>
   </tr>
   <tr>
     <td align="left"><a href="#process">※PROCESS</a></td>
   </tr>
   <tr>
     <td>&nbsp;</td>
   </tr>
   <tr>
     <td><img src="1.png" alt="" width="219" height="300" /></td>
   </tr>
 </table>
 <p>&nbsp;</p>

</div> <div class="bq1" id="apDiv2"><a name="process" id="process"></a><span class="bq3">※PROCESS</span></div> <div id="apDiv8"><a href="#" onMouseOut="MM_swapImgRestore()" onMouseOver="MM_swapImage('Image4','','20090115201834758.jpg',1)"><img src="1.gif" name="Image4" width="129" height="129" border="0"></a></div> <div class="bq1" id="apDiv9"><img src="Tianjin_index15.png" width="45" height="45" align="absmiddle"><a name="motivation" id="motivation"></a><span class="bq3">※MOTIVATION</span></div> <div class="js" id="apDiv10"> <strong>A. Use light instead of strand displacement to open DNA origami. 

 </strong>
 <p>&nbsp;&nbsp;&nbsp; <span class="bq1">Generally  strand displacement is used to open DNA origami. If we use DNA origami to  transport drugs in human body, it&rsquo;s difficult and unsafe to add single-stranded DNA to human body to open DNA origami. So we want to open DNA origami in a  physical way.<br>
 &nbsp;&nbsp;&nbsp; We  want to use light to open DNA origami because light control has many  advantages.</span></p>
 <ol>
   <li class="bq1">light  is cheap and easy to get</li>
   <li class="bq1">it is  convenient to control the intensity of light</li>
   <li class="bq1">light  won&rsquo;t damage human body
     <hr>
   </li>
 </ol>
 <p class="js"><strong>B. Open  different DNA origami selectively</strong></p>
 <p class="bq1">&nbsp;&nbsp;&nbsp; In  severe and advanced tumors, combined drug chemotherapy is gaining importance,  which has already been proven to be clinically successful. Cancer stem cells  that are diagnosed pose a new challenge to existing chemotherapy and radiation  therapies, as they are intrinsically resistant by being inactive or adopting a  drug efflux mechanism or enhanced antiapoptotic protein and DNA repairing  ability. Hence to cure this, drug combinations are explored. In contrast to  single drug chemotherapy, the combined drugs treatment may show additive or  synergistic or antagonistic effects. The pharmaco-kinetics show spotentiative  or reductive responses with reference to the choice of drugs combination.<br>
 &nbsp;&nbsp;&nbsp; For  example, the treatment of advanced breast cancer using paclitaxel and cisplatin  drug combinations indicated a high efficacy in overall response rate. In a  word, the combined chemotherapy strongly demands an efficient delivery vehicle  that can carry multiple cargos to the target site with less accumulation in the  nontarget site so that the trade-off on dosage amount can be brought closer. A  mixed group of DNA origami has the potential to carry different types of drugs. </p>
 <hr>

<p class="js"><strong>C. Transport drugs to tumor site precisely</strong></p> </div> <div class="bq1" id="apDiv11"><img src="Tianjin_index13.png" width="45" height="45" align="absmiddle"><a name="design" id="design"></a><span class="bq3">※DESIGN</span></div> <div class="js" id="apDiv12"> &nbsp;&nbsp; <span class="bq1">The frequence that DNA is used as the engineering material of choice for the construction of nanoscale circuits, structures, and motors is much higher. Many of these enzyme-free constructions function by DNA strand displacement reactions.<br> 

 </span><br>
 <strong>DNA strand displacement </strong><br>
 &nbsp;&nbsp;&nbsp; <span class="bq1">Strand  displacement means that one strand of DNA displaces another in binding to a  third strand with partial complementarity to both. It is highly desireable.<br>
 Strand displacement  is the process through which two strands with partial or full complementarity  hybridize to each other, displacing one or more pre-hybridized strands in the  process. Strand displacement can be initiated at complementary single-stranded  domains (referred to as toeholds) and progresses through a branch migration  process that resembles a random walk. By varying the strength (length and  sequence composition) of toeholds, the rate of strand-displacement reactions  can be quantitatively controlled over a factor of 10^6. Importantly, this  feature allows engineering control over the kinetics of synthetic DNA devices.<br>
 &nbsp;&nbsp; In  molecular biology, strand displacement frequently denotes a process mediated by  enzymes such as polymerases, but the reaction as defined above is guided by the  biophysics of DNA and occurs independently of enzymes.&nbsp; Enzyme-free strand displacement and branch  migration have been studied since the 1970s, but have only been applied to DNA  nanotechnology within the past decade.    </span><br>
 <br>
 <img width="554" height="204" src="wiki-2'_clip_image002_0002.jpg">
 <hr>

<p><strong>Purpose</strong> </p> 

 <p class="bq1">&nbsp;&nbsp; We use DNA sequence to connect the DNA  origami which is loaded with drugs with the Au nanoparticle. And then, on the  one hand, the purpose and the function of this DNA sequence is to release the  drugs after under certain temperature and will never be back to the  nanoparticle. And on the other hand, we hope that it can release different  drugs under different thermal condition.</p>
 <hr>

<span class="bq1"><br> 

 </span><strong>Design </strong><br>
 <strong>Inreversible release</strong><span class="bq1"><br>
 <br>
 &nbsp;&nbsp;&nbsp;&nbsp; To make the  process of releasing drugs inreversible, we need to design a kind of DNA  sequence which will be inactive at the single state, while active when it is  complementary.</span><br>
 <span class="bq1">&nbsp;&nbsp;&nbsp; We find out the hairpin structure which  can exactly suit our idea.<br>
 <img width="147" height="270" src="wiki-2'_clip_image005_0001.jpg" align="left" hspace="12">&nbsp;&nbsp; Because of the toehold&rsquo;s role in  initiating strand displacement reactions, strands can be rendered effectively  unreactive if the toehold domain is made inaccessible by toehold sequestering. Toehold  sequestering can be achieved in a number of ways, the two most common of which  are hybridization of the toehold to a complementary domain and isolation of the  toehold in a short hairpin structure where helix formation is difficult.  Programmed sequestering and subsequent exposure of toehold domains allows  precise control of order and timing over the reactions and has been used in  conjunction with toehold-mediated strand displacement to construct molecular motors,  polymerization reactions, catalytic reactions, and logic gates.</span>
 <hr>
 <p><br>
   <strong>Multistage release<br>
   </strong><br>
   <img width="217" height="164" src="wiki-2'_clip_image008_0000.jpg" align="left" hspace="12"><span class="bq1">&nbsp;&nbsp; To make the multistage release of the  design possible without more difficult steps, we decide to change the tm of the  complementary domain by change the length of one single strand which will be  connected with the DNA origami and drugs.</span><br>
 </p>
 <p><span class="bq1">&nbsp;&nbsp;&nbsp; Like the figure strand A will be connected  with the DNA origami and strand B will combine with the Au nanoparticle.</span></p>
 <hr>
 &nbsp;<strong>Structure</strong><br>
 <span class="bq1"><img src="wiki-2'_clip_image010_0000.jpg" width="127" height="180" hspace="12" align="top"></span>
 <p><span class="bq1">&nbsp;&nbsp;&nbsp; The hairpin  motif like figure comprises four concatenated domains, red yellow blue and  green. And two basic reactions can be programmed using this motif, as  illustrated for the example of catalytic duplex formation in this figure.</span></p>
 <hr>
 <p><br>
 <strong>Assemble</strong></p>
 <p><img src="untitled11.jpg" alt="" width="289" height="265"><br>
   <span class="bq1">&nbsp;&nbsp;&nbsp; First, an  assembly reaction (1) occurs when a single-stranded initiator I, containing an  exposed toehold a*, nucleates at the exposed toehold a of  hairpin A, initiating a branch migration that opens the hairpin. Hairpin  domains yellow and blue were exposed, and can then serve as assembly initiators  for other suitably defined hairpins, permitting cascading (like B&rsquo;s hairpin).<br>
  &nbsp;&nbsp;&nbsp; Second, the same strand displacement  reaction (2) occurs between strand B and A to form the polymer A, B and I.<br>
  &nbsp;&nbsp;&nbsp; Third a disassembly  reaction (3) occurs when a single-stranded domain (yellow domain of B)  initiates a branch migration that displaces the initiator I from A. In this  example, I catalyses the formation of duplex A and B through a prescribed  reaction pathway.<br>
  &nbsp;&nbsp;&nbsp; And finally, the green domain of A and  the blue domain of B partially assemble and open the green hairpin of A. What&rsquo;s  more with the change of the length of the green domain of A, and let the blue  domain of B be always complementary to the loop of the green hairpin, then we  can make the purpose of multistage release.
   </span>&nbsp;<br>
 </p>

</div> <div id="apDiv13"> 

 <p class="js"><strong>Process of our drug  delivery system</strong></p>
 <ol>
   <li class="bq1">Apply magnetic field to transport drug carriers(DNA  origami) to tumor cells directly.</li>
   <li class="bq1">Use  light of low intensity to open DNA origami A and release drug A to kill tumor.</li>
   <li class="bq1">Use  light of high intensity to open DNA origami B and release drug B to kill tumor.
     <hr>
   </li>
 </ol>
 <p><span class="bq1"><br>
  &nbsp; 1.&nbsp; Drive  our DNA spaceship(DNA origami) to a specific planet(tumor cells)<br>
  &nbsp; 2.&nbsp; Use  light of low intensity to open our DNA spaceship, astronaut A(drug A) comes out  and lands on the planet.<br>
  &nbsp; 3.&nbsp; Use  light of high intensity to open our DNA spaceship, astronaut B(drug B) comes  out and lands on the planet.</span><br>
 <img src="wiki-2'_clip_image002_0000.jpg" alt="" width="434" height="239"></p>
 <p class="bq1">&nbsp;&nbsp;&nbsp; Because  our drug delivery system is similar to the real spaceship. Therefore, we termed the project&rdquo;DNA spaceship&rdquo;. </p>
 <hr>

</div> <div id="apDiv14">&copy; COPYRIGHT TJU BIOMOD TEAM 2014, ALL RIGHTS RESERVED</div> <div id="apDiv16"> 

 <hr>
 <p><span class="js"><strong>Release</strong></span><br>
   <br>
 <span class="bq1">&nbsp;&nbsp; With different degrees of heat, the hydrogen bond between these two strands will be broken and the  two strands will be set apart and come back to form two hairpins and can never  combine any more.</span></p>
 <hr>
 <p><br>
   <span class="js"><strong>Logic</strong></span><br>
   <br>
   <span class="js"><img src="wiki-2'_clip_image017_0000.jpg" alt="" width="78" height="85" hspace="12" align="left"></span><img width="190" height="198" src="wiki-2'_clip_image019_0000.jpg" align="left" hspace="12"><span class="bq1">&nbsp;&nbsp; To assist in programming more complex  reaction pathways, we abstract the motif  as a node with four ports  like figure. The state of each port is either accessible (open triangle/circle) or  inaccessible (solid triangle/circle), depending on whether the toehold of the corresponding  motif domain is exposed or sequestered.<br>
    &nbsp;&nbsp;&nbsp; And the secondary reaction mechanism  can use this kind of way to express. </span>
 </p>
 <p class="js">&nbsp;</p>
 <p class="js">&nbsp;</p>
 <hr>
 <span class="js"><strong><br>
 How to open DNA  origami using light signal?</strong><strong></strong></span><strong><br>
 &nbsp; &nbsp; </strong><span class="bq1">This kind of  light control to open DNA origami is achieved by gold nanoparticles(AuNPs). AuNPs can turn light power into heat  power. AuNPs are attached to DNA origami  using DNA linkers. After optical stimulation, the AuNPs will locally generate  heat which breaks the DNA double strands that allow DNA origami to close. Thus  our DNA origami is opened and drug loaded inside is released. AuNPs are like  the keys to open the DNA door of origami.<br>
 <br>
 <img width="273" height="226" src="wiki-2'_clip_image002.jpg"><img width="286" height="167" src="wiki-2'_clip_image004.jpg"></span>
 <hr>
 <p>&nbsp;</p>
 <ol>
   <li class="js"><strong>Details  about properties of AuNPs</strong></li>
 </ol>
 <p class="bq1">&nbsp;&nbsp;&nbsp; Currently a  popular area in nanomedicine is the implementation of plasmonic nano-particles  for cancer diagnosis and photothermal therapy, attributed to the intriguing  optical properties of the nanoparticles. The surface plasmon resonance, a  unique phenomenon to plasmonic nanoparticles leads to strong electromagnetic  fields on the particle surface and consequently enhances all the radiative  properties such as absorption and scattering. <br>
 &nbsp;&nbsp;&nbsp; Plasmon-resonant nanoparticles (NPs) are generating much  enthusiasm due to their extraordinary optical properties, particularly in the  fields of life sciences and medicine. A special property of these  plasmon-resonant NPs is their heat generation upon excitation of the collective  electron resonance by a certain laser frequency. The determination of the  temperature of plasmon-resonant NPs appears essential for a number of different  applications.<br>
 &nbsp;&nbsp;&nbsp; Noble metal nanoparticles, especially gold nanoparticles (AuNPs), have  immense potential for the selective laser photothermal therapy of cancer due to  their ability to efficiently convert surface plasmon resonance-enhanced  absorbed light into localized heat. Gold nanoparticles exhibit NIR activated  photothermal activity due to their geometry dependent plasmon resonance,  resulting from collective oscillation of surface electrons upon excitation with  light at the resonance frequency. Gold is also attractive because due to its  inertness , biocompatibility , low cytotoxicity and long history of medical  use.</p>
 <hr>
 <p class="bq1"><br>
   <span class="js">&nbsp; 2. <strong>We choose NIR laser as our light signal<br>
   </strong></span><br>
 &nbsp;&nbsp;&nbsp; In  recent years, the near infrared (NIR) laser (in the region of 650 to 1100 nm)  mediated photothermal ablation (PTA) therapy has attracted increased attentions  for effective cancer therapy. NIR laser irradiation can induce hyperthermia  damage of cancer cells and tumor organ with deep tissue penetration.  Additionally, PTA also possesses minimal invasiveness and precise  spatial-temporal selectivity in comparison with conventional therapeutic  modalities (i.e. surgical resection, radiotherapy and chemotherapy), since its  therapeutic effect happens only at the tumor site where both light-absorbent  and localized photo-irradiation coexist. Among various NIR absorbents reported  so far, gold nanocrystals (i.e. gold nanorods , gold nanoshells , and gold  nanocages et al.) were most extensively investigated due to their excellent  biocompatibility and tunable surface plasmon resonance (SPR) property to  convert NIR light into local heat.</p>
 <hr>
 <p class="js"><strong> How to open  different DNA origami selectively using light?</strong><br>
   &nbsp; &nbsp;  <span class="bq1">Temperature  increase of Au particle can be calculated. And the temperature increase of Au  particles is related to the intensity and wavelength of light as well as the  diameter of Au particles. Generally, if the other factors remain unchanged, the  more intense light we use, the hotter Au particles could be. We designed two  kinds of DNA origami. These two kinds of DNA origami have different DNA double  lock strands. And melting temperature of this two types of DNA lock strands is  different.<br>
   Initially  we use light of low intensity to irradiate Au nanoparticles. Correspondingly Au particles create a  low temperature increase. DNA lock strands of low melting temperature will  break. And DNA origami with lock strands of low melting temperature on it would  open and release drugs inside. <br>
   &nbsp;&nbsp;&nbsp; Next  we use light of high intensity instead. In the same way DNA origami with lock  strands of high melting temperature on it would open and release a different  kind of drugs inside. <br>
   &nbsp;&nbsp;&nbsp; Thus  with the help of Au nanoparticles we can open different DNA origamis and  release different drugs step by step.</span><br>
   <br>
 <img width="554" height="293" src="wiki-2'_clip_image005.jpg"></p>
 <hr>
 <span class="js"><strong>How to transport  drugs to tumor site precisely？</strong></span><br>
 <br> 
 <span class="bq1">&nbsp;&nbsp;&nbsp; Usually anticancer drugs aren&rsquo;t targeted, which means  they will attack tumor as well as normal cells. To solve this problem, magnetic  nanoparticles(Fe3O4) are attached on our DNA origami to  control the transportation of the DNA origami more precisely. Thus with the  help of magnetic field, drugs can be transported to tumor site directly without  attacking normal cells.</span><br>
 <img width="303" height="289" src="wiki-2'_clip_image006.jpg">

<p class="bq1"><img src="untitled.jpg" alt="" width="363" height="278"></p> <hr> <p class="bq1">&nbsp;</p> </div> <div id="apDiv17"> 

 <object id="FlashID3" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="350" height="300">
   <param name="movie" value="未命名-2.swf">
   <param name="quality" value="high">
   <param name="wmode" value="opaque">
   <param name="swfversion" value="8.0.35.0">
   <!-- 此 param 标签提示使用 Flash Player 6.0 r65 和更高版本的用户下载最新版本的 Flash Player。如果您不想让用户看到该提示，请将其删除。 -->
   <param name="expressinstall" value="Scripts/expressInstall.swf">
   <!-- 下一个对象标签用于非 IE 浏览器。所以使用 IECC 将其从 IE 隐藏。 -->
   <!--[if !IE]>-->
   <object type="application/x-shockwave-flash" data="未命名-2.swf" width="350" height="300">
     <!--<![endif]-->
     <param name="quality" value="high">
     <param name="wmode" value="opaque">
     <param name="swfversion" value="8.0.35.0">
     <param name="expressinstall" value="Scripts/expressInstall.swf">
     <!-- 浏览器将以下替代内容显示给使用 Flash Player 6.0 和更低版本的用户。 -->
     <div>
       <h4>此页面上的内容需要较新版本的 Adobe Flash Player。</h4>
       <p><a href="http://www.adobe.com/go/getflashplayer"><img src="http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif" alt="获取 Adobe Flash Player" width="112" height="33" /></a></p>
     </div>
     <!--[if !IE]>-->
   </object>
   <!--<![endif]-->
 </object>

</div> <div id="apDiv18"> 

 <object id="FlashID4" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="350" height="300">
   <param name="movie" value="未命名-3.swf">
   <param name="quality" value="high">
   <param name="wmode" value="opaque">
   <param name="swfversion" value="8.0.35.0">
   <!-- 此 param 标签提示使用 Flash Player 6.0 r65 和更高版本的用户下载最新版本的 Flash Player。如果您不想让用户看到该提示，请将其删除。 -->
   <param name="expressinstall" value="Scripts/expressInstall.swf">
   <!-- 下一个对象标签用于非 IE 浏览器。所以使用 IECC 将其从 IE 隐藏。 -->
   <!--[if !IE]>-->
   <object type="application/x-shockwave-flash" data="未命名-3.swf" width="350" height="300">
     <!--<![endif]-->
     <param name="quality" value="high">
     <param name="wmode" value="opaque">
     <param name="swfversion" value="8.0.35.0">
     <param name="expressinstall" value="Scripts/expressInstall.swf">
     <!-- 浏览器将以下替代内容显示给使用 Flash Player 6.0 和更低版本的用户。 -->
     <div>
       <h4>此页面上的内容需要较新版本的 Adobe Flash Player。</h4>
       <p><a href="http://www.adobe.com/go/getflashplayer"><img src="http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif" alt="获取 Adobe Flash Player" width="112" height="33" /></a></p>
     </div>
     <!--[if !IE]>-->
   </object>
   <!--<![endif]-->
 </object>

</div> <script type="text/javascript"> swfobject.registerObject("FlashID2"); swfobject.registerObject("FlashID"); swfobject.registerObject("FlashID"); swfobject.registerObject("FlashID3"); swfobject.registerObject("FlashID4"); </script> </body> </html>

Retrieved from "https://openwetware.org/mediawiki/index.php?title=Biomod/2014/wiki-2%27.html&oldid=811686"