# Biohybrid Systems

How do living cells and engineered components share sensing, actuation and control? Covers tissue-powered machines and neural interfaces; wholly biological constructs belong in Origins and Synthetic Life.

## Organism-device integration

- **Cyborg self-regulation** - Clynes and Kline propose extending bodily regulation with technological components for space travel. The organizing idea is an organism-device system whose regulation operates without continuous conscious attention. [Clynes and Kline 1960](<https://faculty.uca.edu/rnovy/Clynes--Cyborgs%20and%20Space.htm> "Cyborgs and Space; Astronautics (institutional transcription)").

## Living actuators and neural interfaces

- **Tissue-engineered swimming ray** - Light-responsive rat heart cells drive an elastomer body with a gold skeleton. Patterned muscle activation produces swimming; externally controlled light frequency and left-right stimulation steer the robot through obstacles. [Park et al. 2016](<https://pmc.ncbi.nlm.nih.gov/articles/PMC5526330/> "Phototactic guidance of a tissue-engineered soft-robotic ray; Science").
    - **Self-paced biohybrid fish** - Opposing cardiac muscle layers and an intrinsic pacing node sustain swimming through mechanoelectrical feedback. Four laboratory-maintained fish retain swimming performance for 108 days, extending the externally paced ray design. [Lee et al. 2022](<https://bpb-us-e1.wpmucdn.com/sites.harvard.edu/dist/6/58/files/2022/03/Lee.etal_.biohybrid.fish_.2022.pdf> "An autonomously swimming biohybrid fish designed with human cardiac biophysics; Science").
- **DishBrain** - Cultured human or mouse neurons control a simulated Pong paddle through an electrode interface. Closed-loop feedback improves the measured play relative to controls; the apparatus supplies the game, encoding and stimulation. [Kagan et al. 2022](<https://pmc.ncbi.nlm.nih.gov/articles/PMC9747182/> "In vitro neurons learn and exhibit sentience when embodied in a simulated game-world; Neuron").
    - **DishBrain interpretation** - Balci et al. question whether the controls and behavioral effects warrant intelligence or sentience claims. Kagan et al. defend a technical definition of sentience; the exchange supplies no independent replication. [Balci et al. 2023](<https://doi.org/10.1016/j.neuron.2023.02.009> "A response to claims of emergent intelligence and sentience in a dish; Neuron"), [Kagan et al. 2023](<https://doi.org/10.1016/j.neuron.2023.02.008> "Scientific communication and the semantics of sentience; Neuron").
- **Brainoware** - An electrode-coupled brain organoid acts as an adaptive reservoir with a trained software readout. Repeated stimulation improves nonlinear prediction and raises eight-speaker classification accuracy from 51% to 78% in five organoids. [Cai et al. 2023](<https://doi.org/10.1038/s41928-023-01069-w> "Brain organoid reservoir computing for artificial intelligence; Nature Electronics").

## Open questions

- How long can an integrated system maintain performance, and which nutrient supply, stimulation and apparatus maintenance does it require?
- Which controls identify the contribution of living tissue separately from the interface and external controller?

## Related topics

- [Hyperorganism](https://hyperorganism.github.io/)
- [Engineered living constructs](https://hyperorganism.github.io/synthetic-life/#minimal-cells-and-engineered-living-constructs) - Wholly biological constructs have a separate home from living-artificial integration.
- [Learning evidence](https://hyperorganism.github.io/basal-cognition/#learning-and-alternative-explanations) - Improved task performance requires controls that distinguish learning from other changes.
- [Consciousness](https://hyperorganism.github.io/consciousness/) - Behavioral adaptation is not a direct assay of subjective experience.
- [Embodiment](https://hyperorganism.github.io/embodiment/)