System and method to simulate hemodynamics
A system for hemodynamic simulation comprises a vessel having properties of a blood vessel, a reservoir containing a quantity of fluid, tubing connecting the vessel and reservoir, and at least one pump for circulating the fluid within the system. Fluid can be tissue culture medium or blood analog fluid, and the vessel may include mammalian cells attached to its inside. A drive system, comprising two reciprocating drive shafts that are coupled by a cam, enables the uncoupling of pulsatile flow and pulsatile pressure to provide independent control over wall shear stress and circumferential strain. The shaft drives two pumps that are 180 degrees out-of-phase and are connected upstream and downstream of the vessel, and effect this uncoupling.
1 . A system configured to produce biomechanical conditions, comprising:
a specimen chamber;
at least one pump positioned upstream of and coupled to an upstream end of the specimen chamber;
at least one pump positioned downstream of and coupled to a downstream end of the specimen chamber, wherein an upstream pump and a downstream pump are coupled to be operated selectively out of phase; and
a reservoir operatively coupled to at least one of the specimen chamber, the upstream pump and the downstream pump.
2 . The system of claim 1 , wherein the specimen chamber, the upstream and downstream pumps and the reservoir are configured to allow fluid to flow therethrough.
3 . The system of claim 2 , wherein the specimen chamber is configured to receive a specimen therein for exposure to at least one predetermined three-dimensional hemodynamic condition.
4 . The system of claim 2 , wherein the biomechanical conditions comprise an in-vivo hemodynamic environment.
5 . The system of claim 4 , wherein the upstream and downstream pumps are configured to produce prescribed longitudinal shear stress and circumferential strain conditions in the specimen unit.
6 . The system of claim 5 , wherein the longitudinal shear stress and circumferential strain conditions produce a prescribed stress phase angle therebetween.
7 . The system of claim 6 , wherein the phase angle is greater than 100 degrees.
8 . The system of claim 2 , wherein the fluid is at least one of substantially liquid, substantially gas, a liquid combined with a solid, a liquid combined with a gas, a gas combined with a solid, and a liquid combined with a solid and a gas.
9 . The system of claim 1 , further comprising a steady flow pump configured to draw fluid from the reservoir and to maintain a flow of fluid into and out of the upstream and downstream pumps.
10 . The system of claim 9 , further comprising an external pump coupled to the specimen chamber and configured to dynamically generate an oscillatory variation in pressure or flow in the specimen chamber.
11 . The system of claim 10 , wherein the pumps each comprise piston or bellows pumps, oscillatory pump, occluders or the like.
12 . The system of claim 1 , further comprising a drive system unit configured to control the pumps, wherein the drive system unit includes at least one of a cam mechanism; a multi-bar linkage mechanism; a solenoid; a stepper motor; an electric motor; a linear ball actuator; a belt-driven actuator; or a chain-driven actuator between two of the plurality of pumps.
13 . The system of claim 1 , wherein the system is configured to produce a plurality of dynamic in-vivo biological conditions.
14 . A method for producing biomechanical conditions, comprising:
providing a specimen chamber;
providing at least one upstream pump coupled to an upstream end of the specimen chamber;
providing at least one downstream pump coupled to a downstream end of the specimen chamber, wherein an upstream pump and a downstream pump are selectively operated out of phase; and
operatively coupling a reservoir to at least one of the specimen chamber, the upstream pump and the downstream pump.
15 . The method of claim 14 , providing a continuous flow path through the specimen chamber, the upstream and downstream pumps and the reservoir, and wherein the specimen chamber is configured to receive a specimen therein for exposure to at least one predetermined hemodynamic condition in the flow path.
16 . The method of claim 14 , wherein the biomechanical conditions reproduce at least one in-vivo hemodynamic environment.
17 . The method of claim 14 , further comprising producing prescribed longitudinal shear stress and circumferential strain conditions in the specimen unit using the upstream and downstream pumps.
18 . The method of claim 17 , wherein the longitudinal shear stress and circumferential strain conditions produce a prescribed stress phase angle therebetween, and wherein the stress phase angle is greater than 100 degrees.
19 . The method of claim 14 , further comprising:
providing a steady flow pump coupled to the reservoir for maintaining a flow of fluid into and out of the upstream and downstream pumps; and
dynamically generating a variation in external pressure or flow in the specimen chamber.
20 . The method of claim 14 , wherein the biomechanical conditions reproduce three-dimensional hemodynamic conditions.