Week 4

Week 4

This week we manufactured the capillary tube with the piercing needle for testing, which will likely happen next week. In addition, the materials we ordered for our experiments arrived, which also means we will likely begin experimentation next week.

Capillary Tube with Piercing Needle Fabrication

In the schematic shown from Week 1, our design requires a piercing needle with a capillary tube. We need the needle to pierce the cap of the VacuStor tube so that the vacuum in the tube is maintained until blood collection. To do this, we took capillary tubes and cut them so that they hold around 100 microliters. Then, we took 21 Gauge 1-inch needles and sawed off the hub where you would put the syringe. We then used an epoxy to stick the capillary tube to the opening of the hub of the needle, and cured the epoxy with the capillary and needle under ultraviolet light.

The result was this:

Capillary Tube with Piercing Needle

We made a few of these to set up for next week's experiments. In addition, the pressure gauges, along with other materials we purchased, have arrived, so we can begin experimentation. We will likely follow a similar experimental setup as the rise time setup, but instead we need to determine a method to have the gauge measure the pressure within the tube, but be able to change the pressure of the tube as well so that we can determine at the lowest pressure difference through which we can still draw fluid through into the tube. We will likely use a three way valve to facilitate this, though a major part of next week will be hashing out how to go about doing this and hopefully running some trials.