Microfluidic device for three dimensional and compartmentalized coculture of neuronal and muscle cells, with functional force readout

1. A microfluidic device for coculture of a muscle cell and a neuronal cell for innervating a muscle bundle, the microfluidic device comprising:

a coculture chamber or a plurality of coculture chambers, each of said chamber comprising:

a first culture compartment including one or more retaining features, the first culture compartment having a width of at least 100 μm;

a second culture compartment including one or more compliant pillars, the second culture compartment having a width of at least 100 μm; and

a buffer compartment separating the first compartment and the second compartment by a distance of at least about 200 μm;

wherein the compliant pillars are deflectable to measure force generated by the muscle bundle and the one or more compliant pillars have a height of at least 50 μm.

2. The microfluidic device of claim 1 , wherein the height is about 50 μm, 100 μm, 150 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 1 mm, or 1.5 mm; and the width of the first culture compartment is about 100 μm, 500 μm, 1.25 mm, 1.5 mm, 1.75 mm, 2 mm, 2.5 mm, 3 mm, 4 mm, or 5 mm.

3. The microfluidic device of claim 1 , wherein the first culture compartment, the second culture compartment, or the buffer compartment includes a volume of at least 650 μm 3 ; or wherein the first culture compartment, the second culture compartment, or the buffer compartment includes a volume of about 650 μm 3 , 700 μm 3 , 750 μm 3 , 800 μm 3 , 850 μm 3 , 900 μm 3 , 950 μm 3 , 1600 μm 3 , or 2100 μm 3 .

4. The microfluidic device of claim 1 , wherein innervating a muscle bundle comprises one or more of

(a) growth of neurites into contact with the external surface of the muscle bundle;

(b) growth of neurites past the external surface and into the muscle bundle; and

(c) formation of a neuromuscular junction between an axon and a muscle cell of the muscle bundle.

5. The microfluidic device of claim 1 , wherein the one or more retaining features comprise a rigid substantially concave barrier, wherein the barrier comprises

(a) about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more are pillars or plates positioned in a substantially concave arrangement; or

(b) a substantially concave wall with slits, holes, or openings too small for a neuron or neurosphere to pass through but large enough for an axon to pass through.

6. The microfluidic device of claim 1 , wherein the first culture compartment contains a neuronal cell, the second culture compartment contains a muscle cell, and the buffer compartment contains a hydrogel.

7. The microfluidic device of claim 1 , wherein the first culture compartment, the second culture compartment, and the buffer compartment contain a hydrogel.

8. The microfluidic device of claim 7 , wherein the hydrogel in the first culture compartment, the second culture compartment, and/or the buffer compartment contains a cell other than the neuronal cell or the muscle cell;

wherein the cell comprises a Schwann cell, an endothelial cell, a satellite cell, or a glial cell;

the neuronal cell comprises a photosensitized cell; or

the neuronal cell comprises a patient-derived neuronal cell from a patient who has been diagnosed with amyotrophic lateral sclerosis (ALS) or spinal muscular atrophy (SMA).

9. The microfluidic device of claim 1 , wherein the neuronal cell

(a) is within a neurosphere;

(b) comprises a neural stem cell;

(c) comprises a neuron;

(d) comprises an interneuron;

(e) comprises a sensory neuron;

(f) comprises a motor neuron;

(g) comprises about 1 to 1000, 100,000 to 10,000,000, 1000 to 1,000,000, or more than 1,000,000 neurons;

(h) comprises a dimension of about 50-2000 microns at its widest diameter;

(i) comprises embryonic neural stem cells;

(j) comprises induced pluripotent neural stem cells; or

(k) comprises a neuron, an astrocyte, and/or an oligodendrocyte; and

wherein the muscle cell

(a) is within a muscle bundle;

(b) comprises a myoblast;

(c) comprises a cardiac, skeletal, or smooth muscle cell;

(d) comprises about 1 to 1000, 1000 to 10,000, 1 to 20,000, or at least about 1000, 5000, or 10,000 muscle cells;

(e) is about 0.5, 1, 2, 3, 4, 5, 2 to 3 or 0.05-5 mm long; or

(f) comprises a cardiac, skeletal, and/or smooth muscle cell.

10. The microfluidic device of claim 1 , wherein an axon extends from the first culture compartment through the buffer compartment to the second culture compartment and forms a three-dimensional neuromuscular junction with the muscle cells.

11. The microfluidic device of claim 1 , further comprising:

one or more neuronal inlet injection ports for seeding the first culture compartment with neuronal cells;

one or more muscle inlet injection ports for seeding the second culture compartment with muscle cells;

a first medium reservoir adjacent the first culture compartment; and

a second medium reservoir adjacent the second culture compartment, the first and second medium reservoirs enabling generation of gradients of growth factors.

12. The microfluidic device of claim 1 , wherein the first culture compartment, the second culture compartment, and/or the buffer compartment comprises a hydrogel.

13. The microfluidic device of claim 12 , wherein the hydrogel comprises an alginate or a derivative thereof, gelatin, collagen, agarose, a natural or synthetic polysaccharide, polylactic acid, polyglycolic acid, poly(lysine), a polyanhydride; a poly(lactide-co-glycolide) (PLGA) polymer, a polyamino acid, a poly(alkylene oxide), a poly(ethylene oxide), a poly(allylamine)(PAM), a poly(acrylate), a polyester, polyhydroxybutyrate and poly-epsilon-caprolactone, a polyphosphazine, a poly(vinyl alcohol), a modified styrene polymer, poly(4-aminomethylstyrene), a pluronic polyol, a polyoxamer, a poly(uronic acid), a poly(vinylpyrrolidone), and/or a copolymer comprising one or more of an alginate or a derivative thereof, gelatin, collagen, agarose, a natural or synthetic polysaccharide, polylactic acid, polyglycolic acid, poly(lysine), a polyanhydride; a poly(lactide-co-glycolide) (PLGA) polymer, a polyamino acid, a poly(alkylene oxide), a poly(ethylene oxide), a poly(allylamine)(PAM), a poly(acrylate), a polyester, polyhydroxybutyrate and poly-epsilon-caprolactone, a polyphosphazine, a poly(vinyl alcohol), a modified styrene polymer, poly(4-aminomethylstyrene), a pluronic polyol, a polyoxamer, a poly(uronic acid), and a poly(vinylpyrrolidone).

14. The microfluidic device of claim 1 , wherein the hydrogel has been crosslinked or may be crosslinked by temperature-induced crosslinking, photocrosslinking, or enzymatic crosslinking.

15. The microfluidic device of claim 1 , wherein the muscle bundle is attached to each of the one or more compliant pillars and a portion of the muscle bundle is wrapped around each of the one or more compliant pillars.

16. A method comprising:

seeding a second culture compartment with muscle cells to enable growth of a muscle bundle, the muscle bundle wrapping around compliant pillars, the second culture compartment forming part of a microfluidic device; and

seeding a first culture compartment with neuronal cells to enable growth of an axon to extend from the first culture compartment through a buffer compartment to the second culture compartment and form a three-dimensional neuromuscular junction with the muscle bundle;

wherein the microfluidic device is for coculture of the muscle cell and the neuronal cells for innervating the muscle bundle, the microfluidic device comprising:

a coculture chamber or a plurality of coculture chambers, each of said chamber comprising:

the first culture compartment including one or more retaining features, the first culture compartment having a width of at least 100 μm;

the second culture compartment including the one or more compliant pillars, the second culture compartment having a width of at least 100 μm; and

the buffer compartment separating the first compartment and the second compartment by a distance of at least about 200 μm;

wherein the compliant pillars are deflectable to measure force generated by the muscle bundle and the one or more compliant pillars have a height of at least 50 μm.

17. The method of claim 16 , further comprising:

stimulating the neuronal cells; and

measure deflection of the compliant pillars that result from contraction of the muscle bundle, the contraction caused by the stimulation of the neuronal cells.

18. The method of claim 16 , wherein microfluidic device further comprises a test compound, wherein the test compound comprises a drug candidate; or the test compound is an organic compound having a molecular weight less than 1000 or 2000 daltons, an RNA interference molecule, a protein, a peptide, an antibody, an antibody fragment, or an aptamer.

19. The method of claim 16 , further comprising:

adding a medium having a first concentration to a first medium reservoir adjacent the first culture compartment to generate a gradient medium within the coculture chamber;

adding a second medium having a second concentration to a second medium reservoir adjacent the second culture compartment.

20. The method of claim 16 , wherein the second compartment includes hydrogel and the three-dimensional neuromuscular junction forms in the hydrogel.