Lipase loaded motion-based multisegmental nanowires for pollutant tributyrin degradation

Nanowires are nanoscale devices that can perform complex tasks and move in liquids. They can incorporate multifunctional segments designed with different materials and therefore have multiple properties simultaneously. Here, the first lipase loaded reduced graphene oxide/nickel/platin nanowires for tributyrin degradation was introduced in this paper. In this study, covalent bonds were formed between the reduced graphene segment of the nanowire and lipase from the hog pancreas via carbodiimide/N-hydroxysuccinimide chemistry. The amount of attached lipase was calculated as 600 mg/g micromotor. The Pt segment in the tail of the nanowire produces O-2 by decomposition of H2O2, and the occurred bubbles allow the nanowires to move by pushing themselves. Ni segment allows the nanowires to be remotely controlled via an external magnetic field, while also allowing the separation of nanowires from the reaction medium. Characterization of nanowires was performed by scanning electron microscopy and energy dispersive X-ray analysis. Activity assays of free lipase and the lipase-loaded nanowires were carried out by using p-nitrophenyl laurate as a substrate. Optimum pH, optimum temperature, and kinetic parameter studies were also performed to show the stability and catalytic activity of the enzyme. Finally, the lipase-loaded nanowires demonstrated good tributyrin degradation capacity (100% at 65 min) with superior reusability properties and directed movement in tributyrin solution.