3D printing is considered a transformational technology; however, its potential for configuring research laboratory equipment is nearly unprecedented. This project uses inexpensive and widely available electronic parts and a commercially available 3D printer to create a USB Powered Autostainer for Biological Specimens.
This platform uses two USB powered stepper motors (one turns the stain tanks into position under the slide and one dips the slide holding biological material into the stain tank), two stepper motor Driver boards, one Arduino UNO microcontroller, one LCD Shield and custom designed ABS plastic 3D printed structural components.

The microcontroller program polls buttons on the Shield to write a 5 step staining protocol. It is fully programmable from this LCD Shield user interface and does not need to be connected to a computer for program control. Each step is written into an element of an array for later program execution. The program first "Homes" the Dip and then the Tank stepper motor against limit switches. The program then executes each movement from the arrays which received the programming steps.

Future developments include inexpensive autostainer platforms for any high school program with access to a 3D printer as well as additional modules for the platform for example an auto-immunostainer or a Thermofoil heated Real Time PCR platform. Since the platform uses only USB power is conceivable that it could be powered by a small solar panel (for field research).

Automated Laberatory Equiptment

• Automated systems are essential in both education and in research.
• Essentially all laboratory equipment uses similar components (optics, fluidics, controlled movements, pneumatics and data management
• Using 3D printed parts and frames allows you to rapidly prototype low cost automated laboratory equipment for Educational uses and for field research.
• Being able to control the movements of automated systems in research or in education can be a tremendous advantage for creating automated systems
• Using USB power allows lower power consumption (USB 4.5 V and 100 mA)
• 3D printed prototype platforms can be Scalable, Modular and Expandable

Stain for Testing the System
Diff-Quik is a commercial Romanowsky stain variant, commonly used in histological staining to rapidly stain and differentiate a variety of smears, commonly blood and non-gynecological smears, including those of fine needle aspirates. It is based on a modification of the Wright Giemsa stain pioneered by Bernard Witlin in 1970. It has advantages over the older Wright Giemsa staining technique, as it reduces the 4 minute process into a simplified 15 second operation, and allows for selective increased eosinophilic or basophilic staining depending upon the time the smear is left in the staining solutions.
Diff-Quik is utilized on material which is air-dried prior to alcohol fixation .

Solutions required:

• Fixative (Fast green in methanol) - pale green colour
• Stain solution 1 (Eosin G in phosphate buffer) - red colour
• Stain solution 2 (Thiazine dye in phosphate buffer) - blue colour

Method:

• Allow smears to dry
• Dip slide five times, for one second each, into Fixative.
• Allow excess to drain after each dip.
• Dip slide or tape-strip five times, for one second each, into Stain

Configuration:

• A portable Up!3D printer was used to fabricate the 3D printed parts. The printer used the following parameters:
  Z Resolution of 0.20mm, Base height 2 mm, Support Density 2 layers, 25% infill of parts interiors. The parts were printed using ABS plastic filament obtained form Octave.com. The parametric files for each object were saved in standard STL (stereolithography) file.
• The Arduino UNO Microcontroller was selected because it permitted an adequate number of digital inputs and outputs to control this prototype while allowing expansion for future development of related systems.
• The stepper motors needed to run with adequate force using USB power. The Steppers were wired as Bipolar motors and the Sparkfun Bipolar motor driver permitted control with the Arduino microcontroller.
• The entire system was designed for low cost (<50$), reliability, low power consumption and portability.

Limitations:

• Platform limited to staining a single slide staining at a time
• This version is limited to 4 staining reservoirs or wells, maximum
• There is no blotting pad or wipe between the staining dips
• Changes in the microcontroller program require computer connection
• The housing for the unit needs to protect the wiring
• The electronics should be embedded in a cowling or cover
• There is currently no way to change the distance that the slide travels

3D printed parts:

• Slide guide -“ guides glass slide
• Limit switch holder (Tank) - Snap-Arm
• Limit switch holder (Slide Dip) proximity
• Support wire guide - supports microscope slide
• Arch - Rotates to Lower glass slide for staining
• Stepper holder (Tank) rotates stain reservoirs
• Tank rotation base, attached to Mentos holder
• Reservoir holder for Mentos containers

FUture Platform Enhancements:

• This flexible platform is:Automated, reliable, programmable, scalable, modular, expandable, inexpensive, with low power consumption, a small footprint and is assembled with 3D printed parts.

• The next generation may include:
• Auto Immunohistochemistry platform, by adding three syringe pumps.
• In situ hybridization platform adding USB powered thermofoil heaters.
• Linked modules to support more complex staining protocols
• Labview control interface or Scratch S4A for more flexible control

This High school science project was overseen by:
Dr. R. Siderits at RWJUHH:

Awards
1) Office of Naval Research Naval Science Award Certificate and a medal
2) AMS Materials Education Foundation for Most Outstanding Exhibit in Materials Science
3) First Place in the Senior division in the field of Engineering Materials and Bioengineering
4) Technology Grant in the form of a microcontroller system called a Beagle board.