Protein-Promoted Synthesis of Pt Nanoparticles on Carbon Nanotubes for Electrocatalytic Nanohybrids with Enhanced Glucose Sensing

A facile and effective strategy to create carbon nanotube (CNT)-based platinum nanoparticle (PtNP) nanohybrids is reported in this work. First, we prepared toluene-soluble CNTs by modifying CNTs with a bifunctional linker, Z-glycine N-succinimidyl ester (Z-Gly-OSu), and then we synthesized super-water-soluble CNT-hemoglobin (HGB) hybrid nanofibers (about 5 mg/mL) by phase-transferring the Z-Gly-OSu-modified CNTs from toluene to HGB aqueous solution. The prepared CNT-HGB nanofibers were used as templates to bind PtCl62- ions by electrostatic interaction between proteins and negatively charged ions. CNT-PtNP nanohybrids were successfully synthesized by chemically reducing the PtCl62- ions with NaBH4. The results indicate that PtNPs with uniform size and shape were created on the side wall of CNTs with high dispersion, and the loading of PtNPs on CNTs was improved with the increase of protein concentration used for the preparation of CNT-HGB nanofibers. A nonenzymatic amperometric sensor for highly sensitive and selective detection of glucose was successfully fabricated as demonstrating based on the synthesized CNT-PtNP nanohybrids. Under optimal conditions, selective detection of glucose in a linear concentration range of 28.0 mu M-46.6 mM (R = 0.996) was obtained, which reveals a lower limit of detection and wider linear response compared to some previously reported glucose sensors.