Functionalization of porous silicon layers for detection of pollutants

In this present work, it was reported the functionalization of porous silicon surface in order to immobilize HRP. Multistep strategy was used allowing maintaining the enzymatic activity. First, acid terminations were generated on hydrogenated PSi surface by thermal hydrosilylation reaction of undecylenic acid with silicon hydrides. Then, the carboxyl-terminated monolayer was transformed to active ester (succinimidyl ester) using N-hydroxysuccinimide (NHS) in the presence of the coupling agent N-ethyl-N´-(3-dimethylaminopropyl) carbodiimide (EDC). Subsequently, the enzyme was anchored on the surface via an amidation reaction. The structure of the modified PSi layers was observed by scanning electron microscopy (SEM). The HRP-immobilized electrode was investigated by cyclic voltammetry (CV). The CV results showed that the modified electrode gave rise to well-defined peaks in phosphate buffer, corresponding to the electrochemical redox reaction between HRP-Fe^III and HRP-Fe^II. The obtained electrode also displayed an electrocatalytic reduction behavior towards H₂O₂.