Synthesis of a CuNP/chitosan/black phosphorus nanocomposite for non-enzymatic hydrogen peroxide sensing.

A copper-chitosan-black phosphorus nanocomposite (CuNPs-Chit-BP) was fabricated by electrochemically depositing copper nanoparticles onto a black phosphorus-modified glassy carbon electrode in chitosan solution. CuNPs demonstrated a uniform distribution on the Chit-BP modified GCE with an average size of 20 nm. Electrochemical methods were used to study the catalytic activity of the CuNPs-Chit-BP nanocomposite toward hydrogen peroxide. The results showed that the synthesized nanocomposite exhibited excellent electrical conductivity, good biocompatibility and highly efficient electrocatalytic activity toward hydrogen peroxide reduction in the range of 10 µM-10.3 mM with a detection limit of 0.390 µM. The present work proposed a new strategy to explore novel BP-based non-enzymatic biosensing platforms.

Synthesis of a Poly-l-Lysine/Black Phosphorus Hybrid for Biosensors.

A simple, noncovalent modification strategy was proposed to synthesize poly-l-lysine-black phosphorus (pLL-BP) hybrid. BP nanoflakes were prepared with a water-phase exfoliation method. pLL can adhere to the surface of BP via hydrophobic interaction between butyl chains of pLL and the BP surface as well as the electrostatic interaction between the protonated amino groups on pLL and the negative charge on deprotonated PxOy groups remaining on BP. The as-synthesized pLL-BP hybrid turns out to be an ideal matrix for hemoglobin immobilization and direct electron transfer. Good conductivity and biocompatibility of BP maintain the native structure and the bioactivity of hemoglobin (Hb), facilitating the direct electron transfer between the electroactive center of Hb and electrode. The rate constant ( kET) for direct electron transfer of Hb@pLL-BP is calculated to be 11.24 s-1. The constructed Hb-pLL-BP based enzymatic electrochemical biosensor displays excellent catalytic activity toward the reduction of oxygen and hydrogen peroxide. The electrochemical response toward H2O2 exhibits a linear dependence on hydrogen peroxide concentration ranging between 10 µM and 700 µM. The results demonstrate that the pLL-BP hybrid can act as a biocompatible building block for the construction of novel biofuel cells, bioelectronics, and biosensors.