Preparation And Research Polydopamine Based Functional Materials

Polydopamine (PDA), a kind of adhesive, hydrophilic and biocompatible macromolecules, has recently been shown to have the ability to adhere on nearly any substrates by simply dipping the substrate in dopamine solution. PDA coatings can serve as a versatile platform for secondary surface-mediated reactions such as electroless metallization and chemical modification. Silver ions in contact with PDA can be reduced in situ into silver nanoparticles (AgNPs) and deposit onto the PDA film. Once dopamine is mixed up with silver ion, PDA-AgNPs complex can be prepared in a one-step method, the oxidization of dopamine and the reduction of silver ion occurs simultaneously. Polydopamine fluorescent organic nanoparticles (PDA-FONs) have the potential of photoluminescence owing to their unique physical and chemical properties. In this work, PDA-based sensors were prepared by layer-by-layer (LbL) technique and in situ reduction method, PDA-FONs were fabricated by ultrasonic oxidation technology, and the details are as follows:1. A nonenzymatic hydrogen peroxide (H2O2) sensor was developed based on PDA/AgNPs multilayer film (PDA/AgNPs)n modified glassy carbon electrode (GCE).(PDA/AgNPs)n was fabricated by alternatively dropping dopamine and silver ion solution on GCE taking advantages of the exceptional adhesive and reductive self-polymerized PDA.(PDA/AgNPs)n was characterized by UV-vis spectrometry, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and X-ray power diffraction (XRD). Electrochemical properties of (PDA/AgNPs)n modified GCE were characterized by electrochemical impedance spectroscopy (EIS). Cyclic voltammetry (CV) study showed that this sensor had a favorable catalytic ability for the reduction of H2O2. The resulted sensor could detect H2O2in a linear range of0.05-1.75mM with a detection limit of6.5uM.2. A nonenzymatic H2O2sensor was developed based on PDA-AgNPs complex film modified GCE. PDA-AgNPs complex was synthesized by one-step method in situ once DA was mixed with silver ions, in which DA acted as a reducing agent and monomer, while silver ions served as the source of the AgNPs and the oxidant to trigger DA to polymerize. PDA-AgNPs complex film was characterized by FE-SEM and XRD. Electrochemical properties of PDA-AgNPs/GCE were characterized by EIS. CV study showed that this sensor had a favorable catalytic ability for the reduction of H2O2. Compared to (PDA/AgNPs)n/GCE sensor, the resulted H2O2sensor has a wider linear range of0.02-8.83mM and a lower detection limit of2.4μM.3. Biocompatible PDA-FONs with tunable photoluminescence were fabricated by ultrasonic oxidation technology. PDA-FONs can be obtained directly by the oxidation of PDA using H2O2under sonication. Morphologies of PDA-FONs were characterized by FE-SEM and Transmission Electron Microscope (TEM). Optical properties of PDA-FONs were characterized by UV-vis and fluorescence spectrophotometer (FL). Fourier Transform Infrared Spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) provide a basis for qualitative analysis of the PDA-FONs. Considering excellent water solubility and biocompatibility of the achieved PDA-FONs, the materials are promising for biomedicine applications.