Heart Valve in a Cube

Introduction

In the current state-of-the-art bioengineered semi-lunar heart valves, stem cells are grown on  a valve shaped biodegradable scaffold. After attaching to the scaffold, cells produce their own extracellular matrix that provides mechanical integrity to the construct. In an alternative approach, heart valves from donor animals are decellularized and repopulated with cells. In both cases, it is necessary to test perfomance of the heart valves under in vivo-like conditions  to optimize their performance.

For testing constructs of murine heart valves with leaftlets a few hundreds of microns is size, microfluidic devices can provide the desirable flow stimulation.

Functional design requirements

The goal is to design and prototype a microfluidic device that has a small chamber filled with cell culture medium and contains two pieces of small diameter tubing with ends ~ 2 mm apart. The chamber must be designed in such a way to allow for reliable suturing of a murine heart valve to the two pieces of tubing. After the heart valve is sutured, it must be possible to hermetically close the device and establish internal perfusion of the heart valve while allowing for imaging the vulvular motion of the leaflets under flow conditions at least at 10x magnification. This is a severe design constrain dictating a design minimizing the distance from the top of the optical window to the leaflets. It is also desirable to interrogate the heart valve by echoing.

Design

Design calls for forming a small cuboidal chamber with two removable sidewalls sealed by O-rings and two pieces of embedded tubing connecting through surface channels to tubing ports on one side of the cube

Isometric view with dimensions

Front view

View depicting chamber and valve ports

Leaflet imaging