Quick and cheap syringe-tubing interfacing

Rodrigo Martinez-Duarte and Marc Madou describe a simple method to connect syringes to chips.

Rodrigo Martinez-Duarte and Marc Madou
BioMEMS Research Laboratory, Department of Mechanical & Aerospace Engineering, University of California, Irvine. Irvine, CA.

Why is this useful?

This tip describes an easy, quick and cheap way to interface syringes to 1/16″ OD (outer diameter) tubing for low and medium pressure applications.  This methodology allows for very quick fabrication with off-the-shelf components as well as modularity since connectors can be easily swapped to other syringes, in contrast to some connecting methods which require connector fabrication for each syringe used.  The connector is very easy to use.

We use 1/16″ OD tubing since many compatible parts such as Y connectors, valves and others are available through online vendors (e.g., Upchurch).

What do I need?

  • 1/16″ OD tubing. A wide variety of tubing materials and sizes are available from Upchurch.  In particular we have used Teflon tubing (catalog number 1620). You could also find the connector at Upchurch (TEFZEL, catalog number P-870)
  • Female Luer to 1/16″ ID (inside diameter) Barbed connector, shown in Fig. 1. A wide choice of materials for connectors are available from Gosina.
  • 3M  Polyolefin Heat Shrink (HS) Tubing 3/64″. Although we have used 3M tubing (Polyolefin Heat Shrink Tubing 3/64″) heat shrink tubing with ID of 1/16″ should work as well. HS tubing is available from a number of suppliers including Fisher.
  • Heating element. A soldering iron would be the most common heating element. You can get a basic one from Fisher (catalog number S50350).

Figure 1. Barbed to female luer connector

What do I do?

1. Wear gloves before starting. You don’t want to introduce impurities during fabrication that could contaminate your device channel in future experiments.
2. Cut around 1 cm of HS tubing.
3. Cut desired length of 1/16″ OD tubing. (If you don’t have a special cutter, use scissors instead of knife to assure a cleaner cut.)
4. Sterilize all components with isopropanol for 2-3 minutes then blow dry.
5. Take the HS tubing. Insert one end to the barbed side of the connector. Make sure tubing is  inserted all the way to the base of the connector (~5 mm).
6. On the other end insert the 1/16″ OD tubing. Insert for around 2-3 mm.
7. Leave around 2 mm of HS tubing length between the barbed connector and the 1/16″ OD tubing; it will allow you to have up to 90 degree angles between your tubing and the syringe since once HS tubing is heat shrunk it will be very flexible.
8. Using the heating element, apply heat along all the HS tubing. Connections will further seal as tubing shrinks. Do not apply too much heat or you might melt the 1/16″ OD tubing or the connector.
9. The finished connector is shown in Figure 2.

Figure 2. Completed connector

What else should I know?

These connectors have been tested with DI water, alcohol, yeast samples, diluted YPD growth medium, air and sodium dodecyl sulfate with reliable performance.

The connector can be dismantled by just pulling components apart. The barbed connectors and 1/16″ OD tubing are not damaged and can be reused.

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