Functionalized Silica Nanotubes As Affinity Matrices for Bilirubin Removal

Arginine-immobilized silica nanotubes as affinity matrices were fabricated for bilirubin removal. The silica nanotubes were prepared by depositing silica within the alumina membrane through sol-gel method. Ligand arginine was immobilized on the inner and outer surfaces of silica nanotubes by activating with glutaraldehyde. The content of arginine of affinity matrices was ~20.1 mg/g nanotubes. Such arginine-immobilized affinity matrices were used to adsorb bilirubin from the bilirubin-phosphate solution and bilirubin-albumin solution. The effects of temperature, ionic strength, albumin concentration, and the adsorption mechanism were investigated by batch experiments. The results showed arginine-immobilized silica nanotubes achieved excellent adsorption capacity for bilirubin (~63.6 mg/g nanotubes).