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Objective
The main goal of this project is to create a device that will replace our sponsor's existing device. Our Tissue Disaggregator will produce a higher yield of viable cells while giving the user the ability to process more than one sample at a time. The device is composed of a few systems that will be described below.
Link to Executive Summary
Heater Block
Our initial concept for our heater module was made of 6061-T6 Aluminum. Below are a few Solidworks renderings of this design.
The design includes slots for heater cartridges. The main purpose of the Heater Block is to maintain the vials at a temperature of about 37°C. A simulation was performed to ensure that the design was able to do this.
With a successful simulation, our team moved on to perform a real life experiment to make sure our concept produced desirable results. As seen below, the temperature control system was able to maintain the heater blocks temperature around 37°C. The controller will bring the heater blocks up to 37°C in less than five minutes at room temperature.
Temperature Controller
The temperature controller that is currently being used is the CAL 3200. This controller was generously donated to us by Hi-Z Technology, Inc.
Agitation System
Currently, we are looking into two methods. The first being a magnetic stirrer and the second being an ultrasonic method.
The diagram to the left is a breakdown of the magnetic stirrer concept we have so far. There are two magnets fixed to a magnetic bracket on the DC motor and when the motor spins it causes a magnetic bar within the vial to spin and stress the tissue sample.
The image on the right is the ultrasonic bath that was chosen to conduct tests with. This particular unit was chosen for its bath size, reasonable price and built-in temperature control.
Magnetic Stirrer Device Prototypes and Slipping of Stir Bar Testing
For our first test, we built a prototype that included temperature control, 3 wells of different diameters, and a magnetic stirrer. The block design was changed for this test so that we could test different vial sizes with the hope that this test could help determine what vial size is optimal.
Slip test was performed on the magnetic stirrer to prevent slipping of stir bar when the motor is in motion. It was found out that a motor of 3000 rpm was good to use where no slipping occurred in its working range.
Micro-controller
The micro-controller chosen for this project is a Raspberry Pi 3 model B. It features a single-board computer with wireless LAN and Bluetooth connectivity.
Display housing
The housing for the Raspberry pi also houses the 7" touch screen and stand. The case is made out of strong ABS plastic and can be wall mounted to conserve lab space.
Ultrasonic Bath Magnetic Rotator
This device will provide magnetic stirring for 3 different vial sizes. The magnets rotate on the outside of the vials to allow ultrasonic waves to propagate to the bottom of each vial. The machined aluminum housing and motor are completely waterproof. The gears are made of nylon and the dry bearings are a PTFE material that will minimize friction and vibration.
Final Design video