Adsorption properties of an activated carbon for 18 cytokines and HMGB1 from inflammatory model plasma

The ability of an activated carbon (AC) to adsorb 18 different cytokines with molecular weights ranging from 8 kDa to 70 kDa and high mobility group box-1 (HMGB1) from inflammatory model plasma at 310 K and the mechanisms of adsorption were examined. Porosity analysis using N2 gas adsorption at 77 K showed that the AC had micropores with diameters of 1–2 nm and mesopores with diameters of 5–20 nm. All 18 cytokines and HMGB1 were adsorbed on the AC; however, the shapes of the adsorption isotherms changed depending on the molecular weight. The adsorption isotherms for molecules of 8–10 kDa, 10–20 kDa, 20–30 kDa, and higher molecular weights were classified as H-2, L-3, S-3, and S-1 types, respectively. These results suggested that the adsorption mechanism for the cytokines and HMGB1 in the mesopores and on the surface of the AC differed as a function of the molecular weight. On the basis of these results, it can be concluded that AC should be efficient for cytokine adsorption.