Alkaline phosphatase biosensors based on layered double hydroxides matrices: Role of LDH composition

Alkaline phosphatase (AlP) biosensors were developed based on the immobilization of this enzyme by adsorption or coprecipitation methods in different layered double hydroxides (LDH) matrices: Zn2Al–Cl and Mg2Al–CO3. Several characteristics of the AlP/LDH membranes, such as the enzyme immobilization procedure, permeability, buffering effect were investigated. It appeared that the basic nature of the MgAl–LDH nanomaterial improved the stability of the immobilized AlP regarding pH. The synergy between the LDH immobilization matrix and the use of hydroquinone diphosphate (HQDP) as substrate provided a very fast and stable response for the AlP/MgAl–LDH biosensors at 0.4 V.