As previously discussed in this newsletter, LAL is the gold standard for endotoxin detection. However, due to limitations, such as assay interference, alternative non-enzymatic alternatives are being investigated regularly.
We recently highlighted an alternative test from China dependent on the release of fluorescent mCherry protein due to activation of NF-kB. Since that time two other alternative approaches have been published. The first, from the University of Urbino in Italy, also used NF-kB expression, this time in MM6 cells, to simulate an innate immune response. The initial tests showed linearity and correlation with LAL but did not provide a clinically relevant minimum detection. The second approach, a collaboration from India, shows promise of a dipstick-type technology that can provide broad endotoxin quantification quickly and without the need for machinery. In this test, spotted endotoxin is detected by binding to polymyxin B and visualized via conjugated gold nanoparticles. The test identified concentrations as low as 10 pg/ml and showed correlation with hematological data.
The continuous push for alternatives to the LAL assay highlight the difficulties associated with an enzyme-based assay. For additional information in overcoming endotoxin masking and/or LAL inhibition/enhancement problems visit our website for information on EndoPrep and ESP.