Making Heart Tissue Dance (2023)
PROJECT DESCRIPTION
In our lab, we exercise engineered heart tissue to try to help it mature. Using tiny exercise machines that we control with precision actuators, we measure and control forces exerted by these small tissue bundles, which are comprised of a few thousand cardiomyocytes grown from stem cells. To further stimulate the tissues during exercise, we provide them with low voltage electrical pulses that cause them to beat like miniature hearts.
This project will involve building a second-generation apparatus that can deliver the programmed electrical pulses to the tissues. Work will include programming an Arduino Uno microprocessor, designing and building a soldered electronic circuit, designing and fabricating an enclosure for the system that includes laser cutting and CAD design and integrates needed components including power, adjustment knobs, and an interactive display. As a final goal, the system will be used to stimulate real tissues in our lab. The specific research goals were to:
• Understand electrical pacing of cardiac tissue: What are current technologies? Why is pacing important? How is it done now? What are the important characteristics of a pacing system?
• Design an electronics circuit using a microprocessor, operational amplifiers, LCD displays, and potentiometers to produce a biphasic 2ms pulse with 10V amplitude at a repetition rate of once per second.
• Build prototypes, simulate design using online software.
• Design and integrate a self-contained enclosure comprising the control circuit, the power supply, the microprocessor, and the display.
• Document the design for open-source replication and use by others in the field.
LABORATORY MENTOR
Ruifeng Hu
LEARNING GOALS
• Tissue engineering: Learn how and why cardiac tissue engineering is a critically important technology that promises a treatment and cure for heart disease.
• Cardiac microtissues: Understand how mechanical and electrical conditioning can benefit engineered heart tissues.
• Electronics/control: Learn how to design and build a useful electronic circuit.
• Computer aided design: Learn how to simulate circuits and structural components to build a prototype system.
• Fabrication: Learn to build a system independently using laser cutting, electrical assembly, soldering, and light machine tools.
Well Plate Reader for Micro-Tugs (2019)
PROJECT DESCRIPTION
In our CELL-MET project, a key building block is the “micro-tug”, a millimeter scale piece of engineered tissue supported like a hammock between two compliant polymer pillars. We use these micro-tugs to evaluate chemical, mechanical, and electrical environmental impacts on tissue health. Our main sensing approach is to measure tissue beat rate and beat force. To date. we have built machines that can use optics to measure one micro-tug at a time. In this project, we will build an instrument that can measure 96 micro-tugs in a 12×8 array simultaneously. The specific research goals were to:
1. Order parts and build microscope based on existing design
2. Develop software to measure force and beat rate in parallel
3. Modify 96 well plates to support micro-tug devices
LABORATORY MENTOR
Marshall Ma
LEARNING GOALS
1. Develop skills associated with design and fabrication of an optical system, including concepts related to resolution, contrast, field-of-view, and optical design tradeoffs.
2. Learn to work on a multi-person team
3. Develop critical thinking and professional work habits in an intellectually challenging environment
4. Become self sufficient in assigned tasks
Using Adaptive Optics to Calibrate Extended Field of Depth Adaptive Scanning Optical Microscope (EDOF-ASOM) with a MEMS Deformable Mirror (2018)
ABSTRACT
Deformable mirrors (DM) are used to improve image quality in microscopy by correcting wavefront errors. These errors are measured with a wavefront sensor (WFS). Image quality improvement is achieved through closed loop feedback control in a process known as adaptive optics (AO). Antonio and Ivanna helped implement and calibrate an adaptive optics system on a new type of microscope: an Extended Depth of Field Adaptive Scanning Optical Microscope (EDOF-ASOM). The EDOF-ASOM instrument can achieve high resolution images over a large volume.
CONCLUSION
We were able to measure and compensate the static aberrations over 31 axial locations for each of 2025 lateral locations using adaptive optics. This calibration took 12 days of continuous closed loop control to complete.
Real-time controlled Incubator and Micro fabricated Platform to Exercise Engineered Cardiac Micro tissues (2018)
ABSTRACT
The CELL-MET team currently makes micro tissues using scaffolds made out of PDMS. Tissue force is measured by optically monitoring PDMS pillar deflection. An extension to this technique is to allow real-time control of micromechanical force in tissue and cellular level . In order to achieve this, PDMS mold structure was re-designed to make a more efficient and easier way to measure and control force. A fast microscope was assembled along with an environmental chamber in order to actively stretch the PDMS substrate with piezo actuators. The environmental chamber was manually built in the lab and using PID control in order to achieve the ideal temperature and ultimately the high humidity and CO2 atmosphere necessary for the cardiac micro tissue cells In vitro.
CONCLUSION
In order for a cell to survive In vitro the chamber must have an atmospheric temperature of 37 degrees Celsius. At a PWM of 40 the temperature steady states at 36 degrees Celsius around 5000 seconds. This concludes that the PI control has worked sufficiently and more efforts to make it work efficiently can be arranged. The next steps would include the humidity and a carbon dioxide control to be tested for further development of our micro tissue Incubator.