Microfludic Setup for Braille Actuated

Microfluidics

MS-BAM

USER MANUAL

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Table of Contents

Introduction………………………………………………………… 1 MS-BAM System Assembly………………………………………. 2 Attachment of Glass Slide & PDMS Chip…………………………. 5 Heater Adjustment/Calibration………….……………………… …. 6 Software Control…………………………………………………… 7 Sub-Assembly of Braille Cell Housing Unit………………………. 9 Sub-Assembly of Braille Cell Actuator Control Box……………… 10 Sub-Assembly of Microscope Slide with PDMS Attached Heater… 11 Sub-Assembly of Stage Blocks to the Main Stage…………………. 11 Safety Guidelines…………………………………………………… 12 Trouble Shooting………………………………………………….... 12 Contact Information……………………………………………….... 13

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MS-BAM USER MANUAL Microfluidics involves the control of fluid flow in miniscule channels ranging from 1-1000 um for a wide range of applications, including cell sorting, localized biochemical treatment of cells using laminar flow, lab-on-a-chip analysis, and high throughput screening of cultured cells. Recently, Braille displays have been used to valve, pump, and regulate fluid movement inside micro-scale channels (or pipes) within chips. A grid of small pins on the Braille display selectively pushes against rubber-enclosed channels near the chip surface in order to squeeze shut certain regions of the channels. Since current microfluidic experimental setups do not allow for real-time monitoring with an inverted microscope, MS-BAM has been created. OPERATIONAL FLOW CHART:

User Microscope Extender XY stage

CircuitrySoftware

PDMS Chip

Braille Cell Actuator

Housing

Planar stage

Chip retention

bar

Cell Culture Image

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INSTRUCTIONS: MS-BAM Assembly:

**To remove the device, follow these set of instructions in the opposite order** 1. Using the Alan

wrench present on the back left side of the microscope, remove the current black Nikon stage. There are two screws present in the front and back of the stage that need to be loosened for removal.

2. Attach the Extender to the XY Stage using the M3 screwdriver. Tighten the pair of M3 screws carefully.

3. Attach the XY-

Stage to the Main stage by properly placing the thumb screws under the two screw holes present on the left side of the main stage. Tighten the thumb screws to the main stage.

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4. Set the Main Stage/XY Stage/Extender onto the microscope as the Nikon stage was. The opening of the stage needs to be located on the right hand side of the microscope

5. Tighten the four screws, two in the front and back, using the same Alan wrench as was used in Step1.

6. Slide the two

threaded rods of the Braille Cell Housing Unit through the two holes in the extender. Fasten the housing unit to the extender using two wing nuts.

7. The final assembled setup should resemble this picture.

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Attachment of Glass Slide and PDMS Chip

1. Attach the custom microscope slide onto the front of the Braille Cell Housing Unit, taking care to align the glass slide in front of the Braille pins. Carefully secure using alligator clips.

2. Slide Microfluidics Chip under the chip retention bar, taking care to align the microfluidic channels with the relevant Braille pins. Push chip retention bar down to secure the Microfluidics Chip and fasten with wingnuts.

3. The assembled Braille Cell Housing Unit should look like this.

*NOTE*

These steps can be completed before or after Step 6 of MS-BAM Assembly

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Heater Adjustment/Calibration 1. Set the power supply to setup A (colored green). 2. Set the voltage to 8V and the current to 320 mA. 3. Connect the black wire from the heater controller box to the negative terminal of

the power supply with alligator clips. 4. Connect the red wire from the heater controller box to the heater and then to the

positive terminal of the power supply with alligator clips. 5. Turn power supply on and wait until the temperature reaches steady state. 6. To increase the heater temperature, turn the screw on the controller box clockwise

or increase the current on the power supply. To decrease the temperature, turn the screw to counterclockwise or decrease the current on the power supply.

7. If the temperature is readjusted, wait 15 minutes for the temperature to reach steady state.

Power Supply Adjusted to 5 V and 320mA

Heater Adjustment with Screwdriver

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Software Control The software package included with this setup is a Windows based .exe file created with Visual C.NET. The software has a windows graphical interface (see below) and uses drivers that control the Braille actuator via USB. To start the software, double-click on the application. The interface is set up so that the user can manually manipulate each pin on the Braille actuator. To raise any pin, simply click on the corresponding checkbox on the computer screen. The user can also set a pump by adding the time delay between each pump stroke (in milliseconds), setting the pump to type 0 for a forward direction and type 1 for a reverse direction, giving the coordinates of the pins for each pump, and finally clicking on the “Set” button.

Software Interface

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Sub-Assembly of Braille Cell Housing Unit

1. Screw in the M4 threaded rods to the backside of the two side pieces.

2. Slide M2 threaded rods through the Braille Cell and side pieces. Secure tightly with wrench. Take extra precaution when working directly with the Braille Cell.

3. In the following order slide the wing nut, chip retention bar, spring, and washer through each M4 screw.

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4. Screw in Chip Retention Bar to the front of the two side pieces. Secure tightly.

5. Attach Microscope Slide Bracket to the front of the Braille Cell Housing Unit with alan wrench

6.Slide the Plexiglas covering over the Braille Cell Housing Unit and carefully secure the pieces.

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Sub-Assembly of Braille Cell Actuator Control Box

1. Attach both 10-pin connector and USB cable to the Braille Cell circuit.

2. Place circuit with

cables attached into the black housing box. Make sure to place wires into the custom grooves at either end of the box.

3. Secure top cover

onto the box. Use a Philips screwdriver to carefully tighten the screws into place.

4. The assembled

Braille Cell Actuator Control Box should look like this.

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Sub-Assembly of Microscope Slide with PDMS Attached Heater - Attach the heater onto the underside of a 75x51mm2 glass slide (provided),

making sure the heater can be place directly underneath the cell culture area of the PDMS chip.

a. Spin coat 1:10 (curing agent:base) ratio PDMS at 500 rpm for 2 minutes onto the glass slide.

b. Set the flat, plastic portion heater onto the PDMS-coated glass slide from one side to another such that no air bubbles become trapped between the PDMS and the heater.

c. Cure the assembly for 1 hour.

Sub-Assembly of Stage Blocks to the Main Stage - To attach the stage blocks to the Main Stage as shown below, begin by finding the

side of the blocks with a center notch and orient that side away from the bottom of the Main Stage. Align each block so that screw holes match, and enter M4, 40 mm long screws into the two larger holes.

Stage Blocks Attached to Main Stage

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SAFETY GUIDELINES: The relevant safety issues with the design involve the electrical and mechanical components. Since we are working with an electrically powered heater and Braille Cell Actuator, electrical shortages are very possible. If an electrical shortage is to occur, not only will the piece of equipment no longer be functional, a fire could also initiate. By housing the Braille Cell Actuator, the design includes the proper precautionary measures to prevent an electrical shortage in this device. Also, specific heaters have been chosen that will work properly when in contact with minimal amounts of fluid, which is likely during the pumping of fluids in the microfluidic setup. The circuitry of the heater which maintains the PDMS chip at a steady temperature of 37±1°C also poses some risk. The circuitry has been sequestered in a box to minimize the risk of liquids spilling and to avoid any electric shock to the user. There is however, one issue that a user should be aware of—the connection between the Braille device and its circuit control box is exposed; any direct contact between the skin and this exposed connection poses the risk of an uncomfortable but fairly harmless electrical shock. The user should further be mindful that the design is made of sharp-edged metals. The user should take care to use the equipment properly and carefully in order to prevent any physical damage. Furthermore, certain screws are exposed and used for tightening and positioning the chip retention device and the housing unit for the Braille Cell Actuator. Although the mechanical and electrical hazards do pose potential hazards, measures (such as the housing unit enclosure) have been taken to reduce risks. In addition, it should be noted that the danger of injury from sharp metallic edges with our design is not appreciably greater than that posed by microscope stages in general. As such, it should pose very little risk to the conscientious user.

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TROUBLESHOOTING:

Pins Fail to Actuate If pins do not rise or are improperly actuating then there may be a disconnection between the user interface and the Braille actuator. Any of the following parts may be not properly used or in need of repair: Braille actuator, software, drivers, USB/wire connection, and circuit board.

1) Check whether USB is plugged in or if the wire to the Braille actuator is connected.

2) Check whether the computer recognizes the USB connection on the lower right Windows panel.

3) If the pins are not actuating in the correct places, try reorienting the direction of the Braille actuator.

Valves/Pump Fail to Work

1) Check to see if the pins are rising. If not, see the section on “Pins Fail to Actuate”

2) Check if the channel is aligned right above the rising pin. 3) If problem is still unsolved, the remaking the chip so that

the channel height is lower and the space between the pin and channel is smaller.

Heater Fails to Turn On (LED is not on)

1) Check that power supply is turned on. 2) Check A/B outputs are set to “A”. 3) Check wires from controller at attached to 3rd set of

terminals (left to right). 4) Check wires to power supply are securely attached at

terminals. 5) Check wire connections to and from controller box.

LED on Controller Box Flashes

1) Disconnect wires from one of the terminals. 2) Set voltage to 12V. 3) Reconnect wire to terminal. 4) Rapidly set current to 320mA. 5) Readjust current as necessary without setting below

250mA.

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CONTACT INFORMATION: - For Questions or Concerns please feel free to contact by email at

weluvbraille@umich.edu or by phone at (734) 223-9626 or (734) 837-8246