Embedded Files
Cutting Device
The sample card holder ensures that the FTA card and clean paper stay down and don’t get pulled up by the punch. It also aligns the FTA card in the correct position. Screws extrude from the four corners of the sample card holder, and get placed into four corresponding slots in the die plate as shown in the figure above. There are four positions to cut in the middle of the four circular sample spaces of the FTA card.
The sample card holder is made from aluminum and a clear acrylic top piece to be durable and easy to clean with bleach solution. It’s easy to disassemble for cleaning also.
Decontamination Method
Our design utilizes a blank paper roll that is placed over the sample card. During a sample punch, the cutting mechanism will cut through the blank paper roll first before the sample card. The user will then remove the sample card and the cutting tool will proceed to punch the clean paper 2 times. The clean paper chads will fall into the same well as the sample since the DNA material will be the same so cross-contamination is not an issue.
This process is outlined in the figure below.
Our single punch design uses a linear actuator with an integrated potentiometer for feedback is mounted to the top of the housing and is driven by a 12V DC motor through a motor shield attached to an Arduino microcontroller. A physical hole-puncher is attached to the shaft end of the linear actuator by a coupler and cuts the FTA card by shearing between the punch and die plate hole.
The components in use include:
Linear actuator with potentiometer
Mounting shafts, bearings, and supports
Physical punch head
Custom made die plate
Sample Card Holder
The decontamination method utilized for the physical punch cutting device involves:
Clean paper roll
Geared motor
Mounting shafts, bearings, and supports
Moveable 96-Well Plate
To increase throughput, our design included a requirement that the 96-well plate could be automatically positioned underneath the sample cutting area. This would allow the cut sample to fall directly into its respective well without any additional effort. To do so, we decided to incorporate an XY stage with an attached plate holder.
The movable based utilized to move the 96-well plate involves:
Purchased XY stage with controller
3D printed 96-well plate holder
Machine Housing
The structural design for the machine housing includes the following components:
80/20 aluminum extrusions
½” thick acrylic base
Corner brackets
Control Interface
The control interface utilizes the capabilities of the Arduino microcontroller to send and receive digital input and output signals for the three main functions of our machine: punch actuation, XY stage movement, and clean paper feeding. By integrating these functions into a simple to use controller, our machine is able to semi-automate the process to increase throughput, reduce human error, and ease use.
Descriptions of each button function is outlined in the table below.
The control interface allows the user to operate the machine via buttons that will send digital IO signals to a microcontroller. The following components are used:
Arduino microcontroller
Motor drivers
XY stage controller
Controller interface box
Page updated
Report abuse