Blue Light DNA Transilluminator
Introduction: Blue Light DNA Transilluminator
Gel electrophoresis arises as an efficient method for comparing various macromolecules such as DNA and RNA based on their size and charge properties. The molecules under analysis are pipetted within a gel made of agarose. The gel is then placed between two electrodes having opposite charges and submerged within an electrolyte buffer solution. An electric field is consequently created once voltage is applied to the electrodes. As a result, the negatively charged molecules gravitate towards the positively charged anode by the action of the electric field. The difference in size becomes apparent as smaller molecules will travel through the gel matrix faster than larger molecules. Further details about the protocols can be found elsewhere. ***
Once the action of the electric field has separated the molecules, a DNA transilluminator is used to observe the location of each molecule within the gel matrix. In detail, the addition of a staining dye within the gel allows the molecules to be fluorescently excited by light having wavelengths within the UV or blue region of the electromagnetic spectrum. Various staining dyes exist with different excitable wavelengths *. A transilluminator is therefore critical for reaching meaningful conclusions from the gel-electrophoresis procedure. However, as demonstrated below, such devices tend to be highly expensive.
Commercially available transilluminators:
* Thermofisher Scientific --> Price: 2200$
* VWR International --> Price: 742$
* Analytik Jena --> Price: 2337$
Students or small laboratories with limited financial support for scientific investigations are often forced to search for alternative methods for analyzing their gels. The present project demonstrates the design and assembly of a DNA transilluminator system using easily accessible components at a respectable cost. The project can be tackled by young students aiming at gaining practical skills in building laboratory equipment or experienced scientists searching for a rapid and cost-efficient method for analyzing gels. 388
The complexity of the project is kept at a minimum. Further modifications can be undertaken to improve the performance of the device. No professional experience in electronics design or software programming is needed.
The project is divided as follow:
1. Gathering the necessary components.
2. Designing and 3D printing the required plastic parts.
3. Assembling the mechanical components.
4. Assembling the electronics components as well as programming the microcontroller.
5. Testing the device and proposing potential improvement.
Step 1: Supplies
* Source of illumination (Blue light 465 - 465 nm) --> LED strip
* 3D Printing Filaments --> PLA Black + PLA Transparent
* Cover Hinges --> Mini Cover Hinges
* Orange UV Shield --> Orange UV Cover Shield
* Microcontroller --> Arduino Nano
* Electronic Switch --> Toggle Light Switch
* Mirror Reflecting Material --> Metalic Mirror Sheet
* Plastic Glue --> Krazy Glue
* Electronics Wires --> Jumper Wires
* PCB Board --> PCB
* DC Power Jack --> Power Adapter
Step 2: Design & 3D Printing
The design procedures have been seperated into three sections:
- Cover (Screen_Perimeters.stl + cover.stl)
- LED Box (Illuminator_Box.stl + Transparent_Glass.stl)
- Electronic Box (Electronics_Box.stl + Box_Cover.stl)
The design of each component was created within Fusion 360 and can be downloaded below:
Fusion 360 Model
Additionally, the STL files required to proceed with 3D printing each component are provided below.
Step 3: Mechanical Assembly
1) Cover Assembly
1.1 --> A small amount of Krazy Glue is deposited onto the black perimeter surface (Labelled as #1).
1.2 --> The orange UV shield (Labelled as #2) is gently deposited onto the black perimeter component having a small amount of glue onto the surface. Wait 5 minutes before proceeding to the next step for the glue to solidify.
1.3 --> Apply a small amount of Krazy Glue onto the interior perimeter of the black upper cover (Labelled as #3). Gently align the upper cover onto the orange UV shield. Wait 5 minutes for the glue to fully solidify.
1.4 --> Briefly measure two equally distanced positions on the exterior of the LED box for gluing two cover hinges. The measurement is only for aesthetic purposes and does not necessarily affect the performance of the unit. Next, apply a small amount of Krazy Glue onto the two selected areas and gently depose one side of the door hinge. Be careful not to apply any glue onto the rotating area. Wait 5 minutes for the glue to be fully solidified.
2) LED Box Assembly
To maximize the reflection of light from the LED towards the UV orange shield, a total of 5 mirror metallic pieces are cut and glued at the bottom of the LED box. 635