Toward pH-controllable bioelectrocatalysis for hydrogen peroxide based on polymer brushes

In the present work, a biosensor was built with smart material based on polymer brushes. The biosensor demonstrated a pH-sensitive on–off property, and it was further used to control or modulate the electrochemical responses of the biosensor. This property could be used to realize pH-controlled electrochemical reaction of hydrogen peroxide and HRP immobilized on polymer brushes. The composite film also showed excellent amperometric i–t response toward hydrogen peroxide in the concentration range of 0–13 μM. In future, this platform might be used for self-regulating targeted diagnostic, drug delivery and biofuel cell based on controllable bioelectrocatalysis.

► A simple method is introduced to synthesize folate-conjugated PEI-CNT nanocomposites.
► The folate-linked nanocomposites enhance detection sensitivity and specificity.
► The cytosensor showed a wide linear detection range for quantifying HeLa cells.
► The strategy could be further used in the early diagnostics of cancer.