pH-Rocker For

DNA-sequencingexperiments

By: Pranav Rathi CHTM-UNM

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Why pH-Rocker was needed?

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• During DNA Sequencing reactions based on quantification of pH measurements for analyzing sequencing reactions, various factors made it difficult to get consistent data. Few of them were changes in pH in stationary reaction mixture and continuously reaction mixture and speed of stirring (done manually). To overcome this, pH rocker was designed to help keep a steady speed for sensor and also to keep a continuous stirring and get a consistent data.

Design of pH-Rocker

Things I Considered for design• Something which can sort of simulate the circular motion by hand• Do not require and advance electronics• Do not require any specific tools or hardware not available in my lab

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Components of pH-Rocker

MB6-thorlabs breadboard

96 well plate

TR12- thorlabs post

TR6- thorlabs post

RA90-thorlabs post clamp

CP02T-thorlabscage plate

CL6 -thorlabs clampPH4-thorlabs

post holder

Poweline variable DC-power supply

PH37-SSHach company pH sensor

PK22G21-hennkwell DC motor

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Construction

Arrange all the parts as shown in the picture.

Stand

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Motor Arm

• This is the most important part of the system; it simulates the arm movement• It is simple to make. I salvaged the black disk from a radio and machined it to fit the motor shaft•I drilled 3 4/40 holes from the edge to put the cage rod• In end to hold the wire I Put 2 wire holder back to back, one of the holders has a 4/40 hole to attach it to the rod.

Black disk

ER1-thorlsba 1’’ cage assembly rod

Linkage throughwire holder

4/40 screws

Rubber cushion

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Arrange the arm

8/32 screw

• I made a 8/32 hole on the cage plate and thread it to hold the motor• Arranged every thing as shown in the picture

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Mount the motor arm on the stand

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Some components

96 well plate

pH Sensor

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The pH- rocker is complete

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