Blood flow simulation

Pulse duplicators, sensors, silicone flow phantoms

1 - Pulse duplicating flow loop built in-house capable of simulating blood-like flow of a blood analog fluid through an silicone-model arterial network. This apparatus is equipped with a magnetic resonance imaging compatible Shelly Medical programmabale pump, a temperature bath, compliance and resistance chambers, flow and pressure sensors. Its modular design permits us to easily fit different test modules for studies. It is currently mainly used for aortic endograft deployment and testing.

2 - Vivitro Pulse duplicator, a turn-key flow apparatus for testing prosthetic heart valve performance and ventricular/aortic blood flow. This vendor-designed apparatus is commonly used in the cardiovascular device industry for pre-clinical implant tests for design and development. The apparatus belongs to Prof. K.B. Chandran, a senior colleague in the Department of Biomedical Engineering. The BioMOST Lab has access to this system and has been used for the design and testing of our novel percutaneous heart valve.

3 - Silicone vascular phantoms are in-house fabricated physical replicas of arteries and aneurysms for flow and implant testing. We make, in our lab, models of idealized or patient-specific (based on diagnostic CT or MR data) vascular structures such as aortic and brain aneurysms. These are fit to the pulse duplicating apparatus for studies on blod flow and implant performance. The silicone models may also be fabricated to match the compliance of the vascular structure in vivo by tweaking the silicone grade used and the wall thcikness of the model.

Want more details? See the pages of the lab's staff and students who focus on this topic - Kathleen Lin, Chaid Schwarz, Benjamin Dickerhoff and Rohini Retarekar

Mechanical Tissue Testing

Uniaxial and multi-axial extension testers, compliance testers

1 - Uniaxial extension tester for assessing uni-dimensional stiffness and strength of biological and prosthetic tissue constructs. A Lloyds Instruments LF-Plus Universal test machine equipped with soft tissue grips and a 50N load cell.

2 - Multi-axial extension tester for assessing the anisotropic multi-directional stiffness of biological tissues and fabrics. Twp custom-built planar radial extension testers are available for studying material symmetries in tissues. Here, a circular specimen is pulled with an equal force in all directions (i.e., radially). If it has any directional preferences, it will turn into n ellipse, revealing the mechanical manifestation of underlying fiber orientations in the tissues that drive such preferences.

3 - Compliance testers for testing tubular stiffness such as arterial or vascular graft complaince. The apparatus allows control of pressures upto 300 mmHg (air or fluid pressure) and estimation of tube-diameters using manual or optical micrometers.

Want more details? See the pages of the lab's current staff and students that focus on this topic - Benjamin Dickerhoff, Manasi Ramachandran, and Rohini Retarekar

Implant fabrication and testing

Shape-memory stents and barbs, cellulose constructs

1 - Shape memory stent and barbs may be fabricated for aortic stent grafts and percutaneous heart valve prostheses. We wrap nitinol wires over custom mandrels to hold chosen stent-arhitecture and heat-treat them to induce shape memory. These may be puled into catheters with minimal damage using an in-house built axisymmetric stent-crimper.

2 - Cellulose constructs for vascular graft or stent coverings may be fabricated using techniques developed by a senior colleague, Prof. Vijay Kumar, Department of Pharmaceutics.

Want more details? See the page of students or staff in the lab who focuses on this topic - Kathleen Lin, Rohini Retarekar, Benjamin Dickerhoff

Software and miscellaneous equipment

High-speed cameras, sensors, software

1 - Software resources are available for computational measurements and modeling research in the lab. They include:
a) Image processing - MIMICS, VMTK, 3D Slicer, 3D-SOM
b) 3D modeling - Rhinoceros 3D, Pro-Engineer
c) Finite element method - ANSYS, ABAQUS
d) Computational Fluid Dynamics - ANSYS (Fluent)
e) Geometric modeling - In-house algorithms
f) Data visualization - Tecplot

2 - Miscellaneous equipment include a high-speed camera, an optical micrometer, vaccuum pumps, and a video borescope

Want more details? See the pages of students in the lab.