Ideal containers for sterilising and storing media or buffer solutions. However, it is strongly recommended that during the autoclaving cycle the caps are only loosely tightened. Heating times are reduced if the steam is easily able to penetrate the contents of the bottle. Loose caps also reduce the risk of failure due to pressure build up inside the bottle. In addition, tightening the screw caps immediately after autoclaving, will result in a vacuum caused by the cooling of the steam. This can lead to bottle failure. To overcome these limitations, the sterile venting membrane screw caps were developed. The screw cap can be tightly closed as the membrane permits an automatic sterile gas exchange, allowing safe pressure equalisation during the autoclave cycle, and at the same time ensuring the sterility of the bottle contents. The microporous structure of the expanded ePTFE membrane enables sterile gas exchange in 2 directions while blocking the flow of high surface tension aqueous liquids.

• The membrane combined with larger vent holes increase the rates of gas exchange.
• Membrane caps can be autoclaved at 121 °C (20 min) or 134 °C (3 min).
• Cost effective as the caps can be reused several times*.
• Biocompatible: the ePTFE filter material conforms to USP <88> 121 °C Class VI.
• The PTFE membrane and its PP mesh support are ultrasonically welded in place forming a durable seal.