Sol-Gel Preparation of Blood-Compatible Titania as an Adsorbent of Bilirubin

This study concerns with the adsorption of pathogenic substances on highly blood-compatible titania and the adsorption mechanism. Titania was prepared through a sol-gel procedure by hydrolyzing tetraethylor-thotitanate and calcining up to 705°C for 3 h. Pore size distribution and surface charge density were measured as a function of calcining temperature. Adsorption of bilirubin, as a typical pathogenic substance, as well as albumin on the titania powder was studied. Bilirubin was adsorbed either in 4 to 8-nm pores or on the surface with a higher positive charge. Thus, either entrapping bilirubin in the pores or electrostatic interaction between bilirubin and titania surface was effective for the adsorption of bilirubin. The titania powder adsorbed a greater amount of bilirubin than the anion-exchange resin used in clinics, hence they have potential for blood purification therapy.