Difference between revisions of "Team:Munich/Hardware/Paperstrip"

 
(10 intermediate revisions by 4 users not shown)
Line 78: Line 78:
 
<!-- Head End -->
 
<!-- Head End -->
 
<!-- Content Begin -->
 
<!-- Content Begin -->
−
<img id="TopPicture" width="960" src="https://static.igem.org/mediawiki/2017/f/fc/T--Munich--FrontPagePicture_Hardware.jpg">
+
<img id="TopPicture" width="960" src="https://static.igem.org/mediawiki/2017/1/17/T--Munich--FrontPagePictures_Paperstrip.jpg">
 
<table width="960" border=0 cellspacing=0 cellpadding=10>
 
<table width="960" border=0 cellspacing=0 cellpadding=10>
 
<tr>
 
<tr>
Line 95: Line 95:
 
<td  colspan = 6 align=center valign=center>
 
<td  colspan = 6 align=center valign=center>
 
<p>
 
<p>
−
To provide a low-cost and durable platform to store the reaction mix for RNA-detection, glass fiber filter paper ((glass microfiber paper 934-AH RTU, Whatman, GE healthcare, Germany) was chosen. To enable transport of the processed sample-containing fluid to the reaction surface, the glass filter paper was embedded in a filter paper sandwich. This sandwich is composed of layers as depicted in figure X (from left to right starting with top layer): One-sided adhesive tape (853 polyester tape, 3M), cellulose filter paper (Whatman® qualitative filter paper, Grade 1, Sigma-Aldrich), double-sided adhesive tape (467MP transfer-tape, 3M), filter paper containing holes for insertion of glass fiber paper and channels for fluid transport onto it, double-sided adhesive tape (3M), cellulose filter paper, one-sided adhesive tape.  
+
To make our readout reaction independent from expensive lab infrastructure, easy to use and storable, we conceived a paper-based solution that complements our <a class="myLink" href="https://2017.igem.org/Team:Munich/Hardware/Detector"> fluorescence detector “Lightbringer”</a> in its design. The<a class="myLink" href="https://2017.igem.org/Team:Munich/Hardware/SampleProcessing">  previously processed</a> patient sample is <a class="myLink" href="https://2017.igem.org/Team:Munich/Hardware/QuakeValve"> pumped</a> onto the paper strip, containing the lyophilized Cas13a reaction mix, and the readout reaction takes place. Here we describe the latest prototype of our paper strip.
 
</p>
 
</p>
 
<p>
 
<p>
−
The one-sided adhesive tapes serve to seal the paper sandwich, the top and bottom paper layers are implemented to avoid sticking of the tapes to the fragile glass fiber paper with loaded reaction mix (red). The middle cellulose filter paper is coated with hydrophobic wax (dark grey) applied with wax printer (Xerox ColorQube 8900) forming hydrophilic channels (light grey) enabling transport of fluid by capillary forces. For precise cutting of holes (white) into the layers of cellulose paper and adhesive tapes (blue), a laser cutter was used.  
+
As regular filter paper shows high auto-fluorescence and therefore conflicts with our detection method, glass fiber filter paper was chosen as substrate for the readout reaction. The glass fiber filter paper is embedded in a sandwich of cellulose filter paper that facilitates transport of the processed sample to the reaction surface via capillary forces. In contrast to glass fiber, cellulose filter paper can be printed with wax<sup><a class="myLink" href="#ref_5">5</a></sup>, allowing the creation of fluidic channels in combination with upper and lower layers of tape. The paper strip is composed of layers as depicted below.
 
</p>
 
</p>
 +
<div class="captionPicture">
 +
<img src="https://static.igem.org/mediawiki/2017/a/a7/T--Munich--Hardware_Paperstrip.png">
 
<p>
 
<p>
−
After assembly from bottom to top guided by orientation marks (6 small holes in every layer), sample can be applied via the inlets (holes on top and bottom in top 3 layers). To avoid interferences with the passing light through auto-fluorescence, layers were designed to have holes above and beneath the glass fiber paper. In a final product, the sealing top- and bottom-layer should be designed to have easily removable, pre-cut strip instead of the plain holes to avoid contamination even for a non-specialized end-user.
+
Composition of the Paper Sandwich.
 +
</p>
 +
</div>
 +
<p>
 +
Starting with the upper layer the sandwich consists of: One-sided adhesive tape<sup><a class="myLink" href="#ref_1">1</a></sup>, cellulose filter paper<sup><a class="myLink" href="#ref_2">2</a></sup>, double-sided adhesive tape<sup><a class="myLink" href="#ref_3">3</a></sup>, filter paper containing holes for insertion of glass fiber paper<sup><a class="myLink" href="#ref_4">4</a></sup> and printed wax channels, double-sided adhesive tape, cellulose filter paper and again one-sided adhesive tape.
 +
</p>
 +
<p>
 +
The one-sided adhesive tapes serve to seal the paper sandwich, the top and bottom paper layers are implemented to avoid sticking of the tapes to the fragile loaded glass fiber paper (red). The middle cellulose filter paper is coated with hydrophobic wax (dark grey) applied with a wax printer, forming fluid channels (light grey). For precise cutting of holes into the layers of cellulose paper (white) and adhesive tapes (blue), a laser cutter was used. The assembly is guided by 6 small alignment marks in every layer.
 +
</p>
 +
<p>
 +
The processed sample and a negative control are applied to the inlets – the large circular holes in the three upper layers. To avoid interferences caused by the light passing through the auto-fluorescent tape, layers were designed with holes above and beneath the glass fiber paper where the detection windows for <a class="myLink" href="https://2017.igem.org/Team:Munich/Hardware/Detector"> “Lightbringer”</a> lie.
 +
</p>
 +
<p>
 +
In a final product, the sealing top- and bottom-layer should be designed to have an easily removable, pre-cut strip instead of the plain holes to avoid contamination by the end-user.
 +
 
  
 
</p>
 
</p>
 +
  
 
</td>
 
</td>
 
</tr>
 
</tr>
  
−
 
+
<tr><td colspan=6 align=center valign=center>
 +
<h3>References</h3>
 +
<p>
 +
    <ol style="text-align: left">
 +
      <li id="ref_1">853 polyester tape, 3M</li>
 +
      <li id="ref_2">Whatman® qualitative filter paper, Grade 1, Sigma-Aldrich</li>
 +
      <li id="ref_3">467MP transfer-tape, 3M</li>
 +
      <li id="ref_4">glass microfiber paper 934-AH RTU, Whatman, GE healthcare</li>
 +
      <li id="ref_5">Carrilho, Emanuel, Andres W. Martinez, and George M. Whitesides. "Understanding wax printing: a simple micropatterning process for paper-based microfluidics." Analytical chemistry 81.16 (2009): 7091-7095.
 +
APA</i>
 +
    </ol>
 +
</p>
 +
</td>
 +
</tr>
  
 
<tr><td class="no-padding" colspan=6 align=right valign=center height=10>
 
<tr><td class="no-padding" colspan=6 align=right valign=center height=10>

Latest revision as of 16:44, 1 November 2017

Description

Design

Demonstrate

Measurement

Applied Design

Final Results

Achievements

Protocols

Notebook

Safety

Parts

Improved Part

Part Collection

InterLab

Model

Software

Collaboration

Detector

Quake Valve

Paperstrips

Sample Processing

Silver

Gold

Engagement

Collaborations

Team members

Sponsors

Attributions

Gallery

Paperstrip

To make our readout reaction independent from expensive lab infrastructure, easy to use and storable, we conceived a paper-based solution that complements our fluorescence detector “Lightbringer” in its design. The previously processed patient sample is pumped onto the paper strip, containing the lyophilized Cas13a reaction mix, and the readout reaction takes place. Here we describe the latest prototype of our paper strip.

As regular filter paper shows high auto-fluorescence and therefore conflicts with our detection method, glass fiber filter paper was chosen as substrate for the readout reaction. The glass fiber filter paper is embedded in a sandwich of cellulose filter paper that facilitates transport of the processed sample to the reaction surface via capillary forces. In contrast to glass fiber, cellulose filter paper can be printed with wax5, allowing the creation of fluidic channels in combination with upper and lower layers of tape. The paper strip is composed of layers as depicted below.

Composition of the Paper Sandwich.

Starting with the upper layer the sandwich consists of: One-sided adhesive tape1, cellulose filter paper2, double-sided adhesive tape3, filter paper containing holes for insertion of glass fiber paper4 and printed wax channels, double-sided adhesive tape, cellulose filter paper and again one-sided adhesive tape.

The one-sided adhesive tapes serve to seal the paper sandwich, the top and bottom paper layers are implemented to avoid sticking of the tapes to the fragile loaded glass fiber paper (red). The middle cellulose filter paper is coated with hydrophobic wax (dark grey) applied with a wax printer, forming fluid channels (light grey). For precise cutting of holes into the layers of cellulose paper (white) and adhesive tapes (blue), a laser cutter was used. The assembly is guided by 6 small alignment marks in every layer.

The processed sample and a negative control are applied to the inlets – the large circular holes in the three upper layers. To avoid interferences caused by the light passing through the auto-fluorescent tape, layers were designed with holes above and beneath the glass fiber paper where the detection windows for “Lightbringer” lie.

In a final product, the sealing top- and bottom-layer should be designed to have an easily removable, pre-cut strip instead of the plain holes to avoid contamination by the end-user.

References

  1. 853 polyester tape, 3M
  2. Whatman® qualitative filter paper, Grade 1, Sigma-Aldrich
  3. 467MP transfer-tape, 3M
  4. glass microfiber paper 934-AH RTU, Whatman, GE healthcare
  5. Carrilho, Emanuel, Andres W. Martinez, and George M. Whitesides. "Understanding wax printing: a simple micropatterning process for paper-based microfluidics." Analytical chemistry 81.16 (2009): 7091-7095. APA