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Developing a pump-micromanipulator duo to study cell response to chemokine for targeted immune response
Spring 2023 MAE 156B CAPSTONE PROJECT
UNIVERSITY OF CALIFORNIA, SAN DIEGO
SPONSORED BY: DR. TRACY HANDEL, DR. CATHERINA SALANGA, AND DR. LEIRE BORREGA ROMAN
Overview
Immune cells play an important role in maintaining health against physiological insults such as cancer and physical trauma. Monocytes, a type of immune cell, follow an increasing gradient of the chemokine CCL2 to address these insults, but little is known regarding the interaction between the CCR2 chemokine receptors on the monocytes and the chemokine CCL2. Our team aims to develop a microinjector system to allow the study of the cell migration in vivo such that the CCR2-CCL2 can be further studied upon. Understanding this interaction can enable targeted treatment of physiological insults via chemokine injection.
Red circles include chemokine CCL2.
Sponsors' initial design solution of a clamp-mounted microinjector system.
Sponsors
The sponsors of this project are Dr. Leire Borrega Roman, Dr. Rina Salanga, and Dr. Tracy Handel. Dr. Handel is the director of the Handel Laboratory, where Dr. Borrega Roman and Dr. Salanga are researchers under Dr. Handel.
Dr. Borrega Roman is a postdoctoral researcher, focusing on the study of the chemokine receptor CCR2, which is an important substance for the functioning of the immune system.
Dr. Salanga is a project scientist with a strong background in biochemistry and cell biology. She has coauthored many manuscripts in chemokine-related studies, such as chemokine-carbohydrate interactions and chemokine-receptor signaling.
Dr. Handel is the director of the Handel Laboratory. Leading the Handel Laboratory to study the structure and function of chemokines and chemokine receptors. The laboratory also studies the structural and dynamic basic for receptor activation to facilitate drug discovery.
More information about the sponsors can be found at this link: https://pharmacy.ucsd.edu/sites/pharmacy.ucsd.edu/files/labs/handel/index.shtml
Initial Solution
The sponsors had the initial design of mounting a micromanipulator to the edge of the microscope stage, then controlling the orientation and the position of the pump relative to the stage. However, the movement of the stage itself operated differently than expected such that the clamp is unable to get a good grip if the stage moves.
On the Nikon Eclipse Ti Inverted Microscope, the top of the stage moves, but the bottom does not.
Thus, our team proposed a standalone micromanipulator design, which will set on top of a static object or on the stage, to allow the stage to move.
Nikon Eclipse Ti Inverted Microscope setup.
Nikon Eclipse Ti-2 Inverted Microscope setup.
Primary Goals and Objectives
Refining the initial requirements the sponsors have put forth for our team, the primary objectives the system must achieve are as follows:
Slow injection rate
Slow injection rate
2 nl/s - 10 nl/s
Adaptable
Adaptable
Adapt both Nikon Eclipse Ti and Ti2 Inverted Microscopes
Inertness
Inertness
Materials do not stick or react to chemokine
Final Design
The final design incorporates:
An RWD R-480 Nanoliter pump that can fill, empty, and inject fluids between 0.02-200 nl/s.
A manual rotation arm with a 22.5:1 gear reduction.
A micromanipulation stage with 4.5 mm x 4.5 mm of movement with nanometer precision.
A controller that toggles stage speed between 8.33 um/s and 333 um/s.
In addition,
A scissor stand and Z-axis stage manipulator for microscope compatibility.
A detailed description of the final design can be found in the Final Design page.
A RWD R-480 Nanoliter pump.
Rate: 0.02-200 nl/s
Max Volume: 5 ul
0.5 um capillary tip
Simple UI interface
A manual rotation arm.
22.5:1 gear reduction (16 deg/rev)
Ergonomic hand cranks (green)
Tightening knobs (black)
348 mm of reach
A micromanipulation stage.
4.5 mm range for each axis
Aluminum machined
Motor speed 0 - 333 um/s
Micro-stepping capability
A controller.
333 um/s coarse speed
8.33 um/s fine speed
Speed toggle (Black button)
LCD visual feedback
Homing (Purple button)
A Z-axis stage.
20 mm range
10 um accuracy
A scissor lift.
80-326 mm range
Inaccurate
Summary of Results
The final hardware possesses the following specifications.
Coarse/Fine Speed: 333 um/s | 8.33 um/s
Travel Range: 4.5 mm x 4.5 mm
Homing Duration: 38 seconds
Step Size: 0.185 um/step
With a target step size of 1 um/step, the device achieves a factor of safety of 5.41.
These specifications allow the sponsors to setup the device quickly and move the tip accurately within the duration of an experiment.
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