Endotoxins are small, stable, bacterially-derived hydrophobic molecules which can easily contaminate labware and whose presence can significantly impact both in vitro and in vivo experiments. Their presence is detected by the limulus amebocyte lysate (LAL) assay which can detect down to 0.01 Endotoxin Units (EU)/ml. Thorough cleanliness in labware, raw materials and in lab technique is required to substantially reduce endotoxin levels. Sigma’s ultrapure HyStem line of products is produced according to these guidelines, yielding a product that is suitable for demanding in vitro and in vivo experiments. The original LAL/TAL method is the gel clot method. In this method equal amounts of a test sample, for instance an injectable chemotherapy solution and the gel clot LAL/TAL are mixed in a test tube. The combined solution is incubated at 37 °C for 60 minutes. After the incubation, the tube is inverted. If sufficient end...
Integrated Drug Discovery Services- Chemistry, Biology & Preclinical Services