What is the Research About?
- This research is focused on using machine learning (ML) and bioelectronics to control cells in real-time. This is achieved through bioelectronic devices that can sense and regulate certain biological processes, especially related to cell voltage (Vmem).
- Bioelectronics can interface electronic devices with biological systems, and in this study, they aim to control cell functions like differentiation and proliferation using bioelectronic devices.
What is Vmem (Cell Membrane Potential)?
- Vmem is the electrical charge difference across a cell’s membrane. It’s important because it affects cell functions like growth, movement, and communication with other cells.
- Changing Vmem can influence how cells behave, like differentiating into other types of cells or growing in certain ways. This makes it crucial for regenerative medicine and synthetic biology.
What Are Bioelectronic Devices?
- Bioelectronic devices connect biological systems with electronic signals to control biological processes. These devices can either sense or act on biological processes.
- One key challenge is translating biological signals (like ions and molecules) into electronic currents and vice versa. Iontronics solves this by controlling ions directly instead of using traditional semiconductors.
Machine Learning and Bioelectronics
- Machine learning (ML) can help bioelectronic devices adapt to changes in biological systems. In this study, ML is used to control bioelectronic devices that adjust cell membrane voltage (Vmem) by managing the pH of the surrounding environment.
- Using an adaptive ML algorithm, the researchers were able to control Vmem in human-induced pluripotent stem cells (hiPSCs) in real-time.
How Do Proton Pumps Control pH?
- Proton pumps are devices that add or remove protons (H⁺ ions) from a solution. These pumps are used to control the pH of the solution surrounding the cells.
- Changes in pH affect Vmem. Increasing protons (acidifying the solution) causes cell depolarization (lower Vmem), while decreasing protons (alkalizing the solution) causes cell hyperpolarization (higher Vmem).
Setting Up the Experiment
- The researchers used a proton pump array integrated with a machine learning controller to adjust the pH in the system and control the Vmem of hiPSCs.
- Each proton pump in the array controls the pH in a specific area. A fluorescent probe (SNARF dye) is used to measure pH changes in real-time.
Machine Learning-Based Control
- The ML algorithm uses real-time feedback from the fluorescent measurements to adjust the proton pump’s voltage. This process helps the system “learn” how to maintain the desired pH and Vmem level.
- The system adjusts the proton pump’s voltage automatically based on the current state and target goal, effectively “closing the loop” between sensing and actuation.
How Does the Algorithm Work?
- The algorithm doesn’t require prior training. It continuously adjusts and learns based on data collected during the experiment.
- It uses a radial basis function (RBF) neural network, which helps make quick adjustments in real-time based on the measured data.
Experiment Results
- The system successfully maintained control of Vmem in hiPSCs for up to 10 hours.
- Short-term Vmem control was achieved by using various waveforms like triangles, sine waves, and square waves to manipulate the proton pump and monitor cell response.
- For long-term control, the researchers alternated periods of pump activation and resting states, allowing for better regulation of Vmem without overstimulating the cells.
What is the Impact of This Research?
- This study is a proof-of-concept for controlling Vmem in non-excitable cells using bioelectronics and machine learning.
- It opens new possibilities for controlling cell functions like proliferation and differentiation, which can have applications in regenerative medicine and synthetic biology.
- By combining bioelectronics with real-time adaptive control, the system can be used for long-term manipulation of cell behavior.
Conclusion
- This research shows that it’s possible to control the membrane potential of non-excitable cells for extended periods using bioelectronic devices and machine learning.
- The results have significant implications for applications in synthetic biology, regenerative medicine, and bioelectronics, where controlling cell functions is crucial.