P18082: Electrical Bioreactor
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Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase

Software:

  1. Determine how to integrate Adruino into bioreactor concept design with consideration of well plate location and wiring set up.
    • This is important since we do not want outside variables to damage the controller.

Electrical:

  1. Conduct tests with media and various electrodes readily available in the lab: brief observations of physical and chemical changes will be monitored to determine more advanced testing parameters since initial reactions are unknown.
    • This is a crucial component of the analysis to make sure the electrical circuit design will meet the needs of the bioreactor.

Mechanical:

  1. Solutions for mechanically securing the container into the system body will be drafted, modeled, and tested for viability.
    • This will allow a better understanding of how much material and what type will be used to generate the Bill of Materials.

Bio-Medical:

  1. Determined what cell line we are using, SHOCKS2. Currently there was minimal planning and testing on the Bio-Medical side since a majority of Preliminary Design Phase was focused on the Mechanical components before testing can be conducted.

Project:

  1. Continue to assess potential risks with electrode material and configuration.
  2. Demonstrate that our testing methodologies will satisfy all of the Engineering Requirements stated on the Problem Definition Page.

Prototyping, Engineering Analysis, Simulation

P18082 Design Concept 1

P18082 Design Concept 1

P28082 Design Concept 2

P28082 Design Concept 2

Overview: Arduino housing top has curved edges (fillets) that will aid in avoiding interference in sealing the housing. Rails base are used for constraining the 6 well plate in the vertical direction and both have fillets for ease of placement. The base is the bottom for all walls. The back plate lies behind the side walls. Support bracket behind housing top for added strength in the connection between the hinge and the top using nuts as fasteners. Strategic placement of tapped holes and counterbores for no break-throughs. Arduino is sealed from incubator conditions to avoid electrical damage. Back plate and base plate are made of Delrin plastic for frictional and insulation purposes. Delrin is wear resistant, machinable, impact resistant, and moisture resistant.

Future Design Considerations: Clearance for hinge support bracket and nuts. Threaded inserts instead of any tapped holes in plastic. Addition of electrical contact connections and clearance holes for wires. Appropriate tolerance for door fit and function. Addition of handles on sides and on door.

For Pugh Chart Comparisons Currently on Edge: The concept detailed above houses the Arduino above the 6 well plate. The plate is constrained by the base of the bioreactor that it is inserted onto for use. The concept detailed below shows the 6 well plate above the Arduino housing. The plate is held in an elevated position by support brackets.

P18082 Concept Generations Focal Points
Functions Concepts
1 2 3 4
Arduino Housing Location Above Well Plate Above Well Plate Below Well Plate Below Well Plate
Arduino Housing Access Door on Hinge Door on Hinge Sliding Door Sliding Door
Handle Ergonomics Angled Horizontal Horizontal Angled
Spring Mechanism Leaf Spring Spring Detent Spring Detent Leaf Spring
Well Plate Location Bottom of Bioreactor Bottom of Bioreactor Top of Bioreactor Top of Bioreactor
Preliminary Detailed Design Pugh Analysis 1
Concept Design 1 2 3 4
Well Plate Accessibility Datum 0 -1 -1
Arduino Accessability 0 -1 -1
Ergonomics of Handles -1 -1 0
Manufacturing Complexity 0 -1 -1
Weight of Unit -1 0 -1
Sterilization Time 0 -1 -1
Portability 0 0 0
Cell Culture Viewability -1 0 -1
Total -3 -5 -6

Selection Criteria Description

  1. Well Plate Accessibility: Refers to the ease with which an individual may access the cell culture within the bioreactor.
  2. Adruino Accessibility: Refers to the ease with which an individual may access the cell culture within the bioreactor.
  3. Ergonomics of Handles: Refers to the each with which an individual interacts with the bioreactor in terms of portability in and out of the incubator and moving across room location.
  4. Manufacturing Complexity: Refers to the time, and effort, that would be required to build the prototype and integrated control systems.
  5. Weight of Unit: Refers to the weight disruption load of the bioreactor and effort for an individual to lift and place bioreactor onto incubator shelving units.
  6. Sterilization Time: Refers to the time required for sterilizing of the bioreactor including the bioreactor itself and well plate culture assembly.
  7. Portability: Refers to its likeliness to create issues due to size and space consumption as well as the overall hardiness of the system (i.e. whether the device will be able to survive handling by multiple individuals over the course of, at least, 3 years).
  8. Cell Culture Viewability: Refers of the cell culture to be viewed without a microscope to make sure electrode, media, and wiring configurations have good status between cell culture media removal/replacement as well as microscope viewing.
P18082 LabVIEW Controller Design Concept 1

P18082 LabVIEW Controller Design Concept 1

LabVIEW Controller Design Concepts Pros Cons
1
  • Easy to change and read numeric controller for voltage input
  • Boolean is simple "ON" or "OFF" that lights up for voltage preference selection
  • Unable to see voltage input range
  • Boolean button hue is not easy to determine status without contrasting background
2
  • Easy to change and read numeric controller for voltage input
  • Numeric controller is more defined against grid
  • Boolean lights up green to show voltage preference selection
  • Unable to see voltage input range
  • Boolean has no indicator besides button lighted to show voltage preference selection
  • Color change in boolean button is hard to determine against grid background
3
  • Easy to read voltage input number
  • Boolean is simple "ON" or "OFF" for static or cyclic voltage
  • Unable to see voltage input range
  • Boolean has no indicator besides left or right to show voltage preference selection
4
  • Can determine range of voltage input on knob
  • Boolean lights up in yellow to show voltage preference selection
  • Knob does not provide numeric voltage input value
5
  • Can determine range of voltage input on slider
  • Boolean lights up in green to show voltage preference selection: dark background of boolean provides good contrast
  • Slider does not provide numeric voltage input value
P18082 LabVIEW Controller Design Interface Concept 1

P18082 LabVIEW Controller Design Interface Concept 1

Feasibility: Prototyping, Analysis, Simulation

Electrode Material Observations
Voltage 5
Minutes (min) 0 1 3 5
Carbon
  1. Media: pink in color
  2. Electrode: graphite colored matte finish
  1. Media: no observed physical/chemical change to material
  2. Electrode: no observed physical/chemical change to material
  1. Media: pink in color around negative electrode, bubble formation starting around negative electrode
  2. Electrode: no physical/chemical change to material
  1. Media: yellow color with bubbles around negative electrode cable, bubble formation beginning to form around positive electrode, bubbles travel towards center of individual well
  2. Electrode: bubble formation starting around negative electrode base, otherwise no observed physical/chemical change to material
Stainless Steel
  1. Media: pink in color
  2. Electrode: silver, shiny coat
  1. Media: no observed physical/chemical change to material
  2. Electrode: no observed physical/chemical change to material
  1. Media: media color changes to darker hue around negative electrode, bubble formation beginning to form around negative electrode
  2. Electrode: no physical/chemical change to material
  1. Media: media color continues to darken in hue around negative electrode, bubble formation continues to spread through well plate towards positive electrode
  2. Electrode: pitting formed around stainless steel base in media
Copper
  1. Media: pink in color
  2. Electrode: silver, shiny coat
  1. Media: no observed physical/chemical change to material
  2. Electrode: corroding beginning to form on copper base in media
  1. Media: media color changing to brighter color around negative electrode, bubble formation beginning to form around negative electrode, green hue beginning to form around positive electrode
  2. Electrode: corroding travels up copper base in media
  1. Media: green hue around positive electrode base continues to move across individual well
  2. Electrode: copper base in media corroded
Physical and Chemical Media Observations at 5 Volts

Physical and Chemical Media Observations at 5 Volts

Physical and Chemical Media Observation at 10 Volts

Physical and Chemical Media Observation at 10 Volts

Electrode Observations

Copper:
The copper showed clear signs of corrosion as the submerged surface of the positive electrode turned the tell-tale green during the test. This is most likely due to the acidic nature of the media.
Stainless Steel:
The stainless steel showed significant pitting on the surface of the positive electrode that had been submerged. Sandmeyer Steel Company claims on their website that “Pitting occurs mainly in the presence of neutral or acidic solutions containing chlorides or other halides.” Though there don’t appear to be chlorides or halides in the media, the acidity of the media is the likely cause of the pitting, similar to what happened with the copper.
Carbon:
While the carbon electrodes don’t appear at to have sustained damage, it is difficult to prove that they didn’t react with the media, as the media still changed colors, and experienced significant bubbling.
Thoughts for Moving Forward:
Test again comparing Carbon with Chromium, as Chromium is incredibly resistant to corrosion, even in acidic environments. Use pH testing, and keep track of media loss due to foam production by measuring the amount of liquid media before and after.

Drawings, Schematics, Flow Charts, Simulations

The images below are 3D modeling of the preliminary design concept 1 for the electrical bioreactor. The link provided redirects to the drawing schematics accompanying the design concept shown below.

Link to live P18082 Bioreactor Design 1 Schematics

P28082 Design 1 Oblique View

P28082 Design 1 Oblique View

P28082 Design 1 Front View

P28082 Design 1 Front View

P28082 Design 1 Top View

P28082 Design 1 Top View

P28082 Design 1 Side View

P28082 Design 1 Side View

P28082 Design 1 Back View

P28082 Design 1 Back View

P28082 Design 1 Bottom View

P28082 Design 1 Bottom View

Bill of Material (BOM)

Link to live P18082 Bill of Materials

Test Plans

Preliminary Test Preliminary Test Outline
1. Temperature and Humidity Test
ERS Involved: S5.b and S5.c
Goal: To determine whether the incubator will sustain the conditions required to keep the cells alive.
Equipment Needed: Incubator
Procedure: Place humidity and temperature sensor in incubator; record data over 4 days in 30 minute intervals; collect RH and temperature data using Excel.
2. pH Test
ERS Involved: S2.a , S5.a , and S5.d
Goal: To determine whether the incubator will maintain the pH required to keep the cells alive.
Equipment Needed: Incubator, 6-well plate, media, pH probe/litmus paper.
Procedure: Put media in 6-well plate and place plate in incubator; take pH reading every day for 7 days; record in Excel.
3. Electrode Durability Test
ERS Involved: N/A
Goal: To determine the lifetime of the electrodes.
Equipment Needed: electrodes, 6-well plate, media, litmus paper/pH meter
Procedure: Put media in 6-well plate and place plate in incubator with electrode and microcontroller (take picture of electrode before added to media); ensure electrode hasn’t changed the color of the media, pH of media, and eroded (take picture of electrode at the end and compare).
4. Microcontroller Durability Test
ERS Involved: N/A
Goal: To determine the lifetime of the microcontroller.
Equipment Needed: Electrodes, 6-well plate, media, microcontroller
Procedure: Put media in 6-well plate and place plate in incubator with microcontroller; ensure microcontroller is still working by testing feedback system.
5. Voltage Test
ERS Involved: S2.e and S2.f
Goal: To determine if the system applies a measurable voltage across the cell culture.
Equipment Needed: Media, microcontroller
Procedure: Connect two wires, instead of one, to the electrodes; extra wire is used to verify the voltage.
6. Accessibility Test
ERS Involved: S3.a
Goal: Determine whether the mechanism for holding the culture system is usable.
Equipment Needed: 6-well plate, system (overall), spring/locking mechanism.
Procedure: Observe mechanism for mechanical issues; insert plate into holding spot; release plate from holding spot; repeat action several times to observe any immediate wear issues.
7. Assembly Test
ERS Involved: S3.a and S3.b
Goal: To determine how long it takes to assemble the reactor from gathering materials to putting into the incubator
Equipment Needed: Electrodes, 6-well plate, media, microcontroller.
Procedure: Set-up by gathering 6-well plate and adding media to plate.
8. Cleaning Test
ERS Involved: S3.b
Goal: Identify the time required to (deep) clean the system and issues resulting due to system material properties.
Equipment Needed: Autoclave, system (overall).
Procedure: Obtain time slot in autoclave to perform (deep) cleaning of system; determine whether proposed materials are compatible in autoclave.
9. System Durability Test (this may require durability tests of multiple components)
ERS Involved: N/A
Goal: Ensure that system will be able to withstand “bumps” (not necessarily a drop).
Equipment Needed: System (overall).
Procedure: Perform some light batting; (maybe) perform a controlled drop.
10. Ease of Use Test (Control System)
ERS Involved: S2.g and S3.c
Goal: Determine intuitiveness of LabVIEW controls and robustness of our LabVIEW/Arduino interfacing.
Equipment Needed: LabVIEW (and control dashboard), Arduino, cable connection, computer, victim undergraduate student
Procedure: Perform troubleshooting of software; have individuals not involved with project observe the control dashboard.
11. Handling/Size Test
ERS Involved: S2.b and S2.c
Goal: Determine whether system will remain within allowable system dimensions.
Equipment Needed: Measuring tape(?), incubator, microscope (generic, Leica, EVOS).
Procedure: Record dimensions of system; place system in incubator on a middle shelf and observe if dimensions are in tolerance; place system in each of the 3 microscopes and observe if dimensions are in tolerance.
12. Sterilization Test
ERS Involved: S1.a
Goal: Verify that system (culture and overall) is resistant to ethanol.
Equipment Needed: Ethanol, safety goggles, rubber gloves, 6-well plate.
Procedure: Perform aseptic sterilization technique on 6-well plate and overall system; observe openings, crevices, etc. where ethanol may breach system; plan/repair issues that arise.
13. Safety Test
ERS Involved: S4.a
Goal: Ensure that system does harm student (e.g. shock, cut, bruise, etc.).
Equipment Needed: Duct tape, protective gloves.
Procedure: Perform visual inspection of system; perform electrical test of system.

Risk Assessment

The Risk Assessment is carried over from previous Design Reviews with the added risks of electrode complications.

Currently electrodes are chemically reacting with the media which includes and is not limited to the following: pitting, corrosion, acid-base reaction, decomposition reaction.

Link to live P180821 Risk Assessment Preliminary Design

Plans for next phase

As we move towards the end of MSD I, we must solidify our design specifications, and make manufacturability plans that will allow us to build the first full prototype in February 2018, so that the iterative process of testing and design changes can begin in early March.

Mechanical:

- The six-well plate securing mechanism needs to be drawn up for production
- The drawings should be finalized and ready to be used in January

Electrical

- More testing needs to be conducted to determine which electrode material to use
- Circuit Diagrams/Schematics should be finalized
- A Digital-to-Analog-Converter (DAC) should be compared against Pulse-Width-Modulation to determine which is better for inducing a cyclic voltage on the media

Biological

- Assist with the electrode testing by measuring the effects of the electrodes and voltages on the media (i.e. pH, color, mass retention, etc.)
- Make final preparations to ensure that all necessary testing materials and equipment will be ready MSD II

Managerial

- Create clear vision and schedule for December through the end of February
- Ensure all necessary tasks are met
- Prioritise risks, making sure to tactical the highest risks first

Logistical

- Make any necessary final changes to the Bill of Materials
- Go back through the risk assessement to check of things that have been adressed, and make sure new risks have been added

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