Nanotube-doped alginate gel as a novel carrier for BSA immobilization

In this paper different dopants, including carbon nanotubes (CNTs), silica nanotubes (SiNTs), graphite and silica gel, were incorporated into alginate (ALG) gel to form nanotube/alginate or nanoparticle/alginate composites used for bovine serum albumin (BSA) immobilization carrier. During encapsulation, first BSA was adsorbed on the dopants, and then BSA and dopants were suspended in alginate solution, followed by being added dropwise into the CaCl2 solution to form the biocomposites. The BSA leakage decreased significantly in these biocomposites as the following order: BSA-ALG-SiNT > BSA-ALG-CNT > BSA-ALG-SiO2 > BSA-ALG-graphite, which was mainly due to firstly the protein molecule adsorption on the dopants which could not be washed out easily and secondly, during the biocomposites formation, water loss in BSA-ALG-dopant biocomposites became less than that in BSA-ALG biocomposite. In addition, the mechanical properties of these biocomposites were remarkably reinforced in the same order as BSA leakage decrease.