Endotoxin activity measured by limulus assay

The binding activity of endotoxin (Escherichia coli 0111) to dentin powder pre-treated with 10% sodium hypochlorite and with 3% hydrogen peroxide was investigated. This was carried out for periods of 30, 10 and 1 min. The endotoxin was diluted into 100 ng/ml solutions. Dentin powder suspended in a 34 micrograms/ml protein concentration was used in the study. The limulus amoebocyte lysate test was used to determine the amount of endotoxin binding, which was measured by the microtiter plate reader. The binding activity level of that concentration of endotoxin was significantly lower in dentin powder treated with 10% sodium hypochlorite than in that treated with 3% hydrogen peroxide at 1 and 10 min. Endotoxin binding activity measured the lowest in the 30 min test period.