Nanozyme: Synthesis, Characterization, and Its Application to (Bio)chemical Sensing

Abstract

Nanozymes refer to nanomaterials that possess enzyme-like characteristics. Using nanomaterials to mimic the function of protein enzymes is an interesting idea. Nanozymes are of considerable interest because of great promise for catalytic activity. Many typical enzymatic reactions mimicking oxidases, peroxidases, catalases, and superoxide dismutases have been realized by simple nanomaterials (e.g., gold, platinum and carbon nanotubes). And the synthesis and characterization of nanozymes have developed to an impressive level with exquisite control in size, shape, and composition. In this thesis, we synthesized and characterized several typical nanozymes and then focus our attention on their enormous applications with respect to electrochemical (bio)sensor and colorimetric sensor. First, we introduce a method for precise, controllable patterning Au-Pt alloy nanoparticles on single-walled carbon nanotube (SWCNT) thin film using electrochemical deposition. The process includes the fabrication of SWCNT film by vacuum filtration method and the patterning of the photoresist polymer by photolithography. Subsequently, the alloy nanoparticles are deposited on the pre-pattern SWCNT film by electrochemical deposition method. The patterned SWCNT thin film of Au-Pt alloy nanoparticles as substrate for electrochemical (bio)sensor for the detection of hydroxylamine. Furthermore, we demonstrated a method for colorimetric detection of H2O2 and Hg2+ based on the gold-SWCNT hybrids as nanozymes which exhibit peroxidase-mimicking activity. Finally, the nanozyme-based paper device with quantitative POC colorimetric analysis was studied. The prepared colorimetric assay exhibited a high sensitivity, low detection limit and low cost. Our results demonstrated that the proposed nanozyme-based colorimetric assay is capable of facilitating on-site monitor and control mercury environmental pollution.