For research infusing or sampling from laboratory animals, keeping the fluid path sealed off from bacteria and air is critical for maintaining patency and avoiding infection. If you are using a Vascular Access Button™ instead of an externalized catheter you have solved the problem at the animal connection point. But what about the connection to your syringe? An open luer connection defeats the closed system, particularly if you are changing syringes during a study. You could use a PinPort™ connection, but these are not designed to lock together the way luers do. The needlefree Rymed® luer connector solves this problem, and it's now available from Instech.
The Rymed InVision-Plus® port seals when disconnected, but opens when connected to the male luer on a syringe. You can use aseptic technique, swabbing the septum, prior to connection. The port has a 27 microliter priming volume, but almost magically it does not pull back fluid when disconnecting or push it forward when connecting: it has neutral fluid displacement.