Muscle-powered biological machines
The present disclosure provides a biological machine comprising a skeleton comprising at least one hydrogel strip and at least two hydrogel bases, and at least one bioactuator, the at least one bioactuator comprising at least one muscle ring, the muscle ring comprising skeletal muscle cells, wherein the muscle ring is tethered around the at least two pillars. The muscle ring can comprises skeletal muscle, and skeletal muscle innervated with motor neurons, allowing chemical control of muscle contraction. Methods of making the biological machine is also provided.
1. A biological machine comprising:
a skeleton comprising two or more hydrogel pillars having top and bottom base end surfaces, wherein the two or more hydrogel pillars are coupled to one or more hydrogel beams at their top base end surfaces, wherein the hydrogel beam extends between the two or more hydrogel pillars; and
at least one layered tissue ring comprising a first ring shaped layer comprising differentiated myoblasts in a gel; and a second ring shaped layer comprising motor neurons;
wherein the first and second layers are fused into a layered tissue ring;
wherein the layered tissue ring surrounds the two or more pillars.
2. The biological machine of claim 1 , wherein the two or more hydrogel pillars have caps on their bottom base end surfaces.
3. The biological machine of claim 1 , wherein the differentiated myoblasts are elongated, contractile myotubes.
4. The biological machine of claim 1 , wherein the biological machine has active force generation of about 150, 200, or 300 μN or about 0.3, 0.4, or 0.5 kPa.
5. The biological machine of claim 1 , wherein the one or more layered tissue rings have motor neuron induced muscle contraction.
6. The biological machine of claim 1 , wherein the layered tissue ring contracts in response to electrical stimulation, chemical stimulation, optical stimulation, or combinations thereof.
7. The biological machine of claim 1 , wherein the motor neurons are responsive to at least one excitatory neurotransmitter.
8. The biological machine of claim 7 , wherein the at least one excitatory neurotransmitter is glutamate.
9. The biological machine of claim 1 , wherein the layered tissue ring comprises neuromuscular junctions.
10. The biological machine of claim 1 , wherein one or more of the cells of the layered tissue ring express one or more heterologous light-sensitive proteins.
11. The biological machine of claim 1 , wherein the biological machine is capable of locomotion.
12. A method of making the biological machine of claim 1 , comprising:
(a) making the two or more hydrogel pillars coupled to one or more hydrogel beams with a stereo-lithographic apparatus or a molding apparatus and polymerizable liquid materials;
(b) making a layered tissue ring; and
(c) surrounding the two or more pillars with the layered tissue ring.
13. A method of inducing the biological machine of claim 1 to locomote comprising contacting a portion of the layered tissue ring or the entire layered tissue ring with light, electrical pulses, or a chemical capable of inducing contraction of the layered tissue ring such that the biological machine locomotes.
14. The biological machine of claim 1 , wherein the motor neurons of the second ring shaped layer are present in a gel.
15. The biological machine of claim 1 , wherein the layered tissue ring is 500 to 750 μM thick.