Magnetic layered double hydroxide nanosheet as a biomolecular vessel for enzyme immobilization

Magnetic nanoparticle coated with manganese-aluminum layered double hydroxide (Fe3O4/Mg-Al-CO3-LDH) was prepared and used as porous support for ficin (EC 3.4.22.3) as a model enzyme. Structural characteristics were studied by XRD, FTIR, SEM and light scattering. The quantity of immobilized ficin on the mentioned LDH and non-magnetic LDH was measured and enzyme activity, stability and reusability were compared. Results revealed that the core and shell structure of Fe3O4/Mg-Al-CO3-LDH makes it better dispersion compared to the pristine Mg-Al-CO3-LDH. Ficin showed strong affinity to absorption of the surface of mentioned LDHs nanosheet especially magnetic LDH, confirmed that the existence of Fe3O4 in the core structure of magnetic Fe3O4/Mg-Al-CO3-LDH caused better dispersion of LDH nanocrystal shell compared to pristine LDH moreover, enzyme which immobilized on the magnetic LDH supports, can be recovered by magnetic interaction. The storage stability of free ficin, immobilized ficin on the Mg-Al-CO3-LDH and Fe3O4/Mg-Al-CO3-LDH during a period of 120 days lost about 75%, 30%, and 20% of their initial activities, respectively.

Automated summary

A magnetic nanoparticle coated with manganese-aluminum layered double hydroxide (Fe3O4/Mg-Al-CO3-LDH) was used as a porous support for the immobilization of ficin enzyme. The results showed that the Fe3O4/Mg-Al-CO3-LDH had better dispersion due to its core and shell structure. Ficin had a strong affinity for the magnetic LDH support, and the immobilized enzyme could be easily recovered by magnetic interaction. The storage stability of ficin on the Fe3O4/Mg-Al-CO3-LDH was also higher compared to other supports.