Human haptoglobin adsorption by a total internal reflection fluorescence method

Haptoglobin (Hp) is one of the major protein constituents of plasma. Three different forms are found in the population. The 1-1 and 2-2 forms adsorb similarly onto hydrophobic silica [treated with dimethyl dichlorosilane (DDS)] and onto clean silica, although the affinities on the silica surface are lower at 60 minutes contact time. The two forms desorb differently from silica, but desorb similarly from DDS-silica. Adsorption is less reversible on the hydrophobic surface. Due to its adsorbtion tendencies and its high concentration in plasma, the adsorption of Hp may be important in blood interaction at solid-liquid interfaces.