Novel polyurethane ionomer nanoparticles displayed a good biosensor effection

This study described the bioelectrochemistry property of hemoglobin (Hb) on biopolymer film of polyurethane ionomer nanoparticles (PUI-NPs) noncovalently functionalized with multiwall carbon nanotubes (MWCNTs). The polyurethane ionomer nanoparticles (PUI-NPs) were synthesized by emulsion polymerization, and could provide a good biocompatible microenvironment for Hb immobilization. The characteristic of (PUI-NPs)/MWCNTs and Hb/(PUI-NPs)/MWCNTs composite films were performed by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and circular dichroism (CD). Analytical results indicated that the immobilized Hb could maintain its native conformation in the (PUI-NPs)/MWCNTs hybrid film. Entrapped Hb in (PUI-NPs)/MWCNTs preserved its bioactivities and exhibited an excellent electrochemical behavior with a formal potential of −0.346 V in a pH 7.0 phosphate buffer. The formal potential of Hb varied linearly with the increase of pH in the range of 5.0–9.0 with a slope of 52.9 mV pH−1, indicating that one proton participated in the electrochemical reaction process. Moreover, the resulting biosensor displays an electrocatalytic activity to hydrogen peroxide (H2O2). The linear range for the determination of H2O2 was from 6.5 × 10−7 to 8.0 × 10−5 M with a detection limit of 2.4 × 10−7 M and a Michaelis–Menten constant Kmapp value of 0.155 mM. Consequently, our investigation demonstrated that the proposed method opens a way to develop biosensors by using polymer with good biocompatible in its nanostructured information.

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► PUI-NPs combined with MWCNTs to be the immobilization matrix for Hb.
► The linear range for the determination of H2O2 was from 2.0 × 10−7 to 8.0 × 10−5 M.
► The detection limit for determination of H2O2 was 1.2 × 10−7 M.
► The nanocomposite film can provide a favorable microenvironment for Hb to retain its bioactivity.