Based Manganese - Tyrosine Coordination Polymer Electrochemical Biosensor

Metal-organic coordination polymers (MOCPs) possesses large specific surface area, mutil-functionality and structure diversity, so they have become an extremely important research topic in recent year, but they are novel to be used for the development of the high performance enzyme-free electrochemical biosensors, rather limited attention were paid on it. Nano-material presents diversified and unique merits, making it be applicated in many fields. So biosensors based on nanomaterials have become hot topics and focuses. In this thesis, we synthesized nano-scale metal-amino acid polymers, and prepared a new enzyme-free electrochemical biosensor. The main contents are as following:1. The preparation and characterization of nano-scale metal-amino acid polymers Mn-tyr were studied. The polymers were prepared by Mn which owns valence state, unsaturated metal sites and empty d orbitals, and biological molecules L-tyrosine.The acquared Mn-tyr was characterizaed by XRD, TEM, FTIR.,etc.TEM results indicated that Mn-tyr nanostructures had nanorods with an size of100-200nm in wideth and2-4μm in length, the particles well dispersed and no impurities were found. As metal-organic coordination polymer has potential application in many aspects such as magnetic, optical, electrical, adsorption and catalytic, we have explored it’s application in electrochemical biological sensing, and found that the polymer has a notable bifunctional catalytic activity towards the oxidation and the reduction of H2O2at neutral pH, oxidative determination was found to be more efficient than the reductive detection. With the addition of SWCNT,the biosensor shows better property. And it is interesting to note that there are more three quasi-reversible redox peaks in the potential range of-0.4V-0.4V, then we used these peaks to detect hydrogen peroxide, The sensor exhibits excellent catalytic activity toward the reduction of H2O2and displays a rather wide linear range (10-6～1.02×10-4M), high sensitivity (494mA mol-1L cm-2)and a low detection limit (5.6×10-1M).2. A novel manganese coordination polymer Mn-tyr was obtained. The Mn2O3nanostructures have been prepared via thermal decomposition of as-prepared manganese polymer Mn-tyr. Different approaches such as X-ray diffraction (XRD) and transmission electron microscopy (TEM) were applied to characterize the products. TEM images and XRD analysis indicated that the as-synthesized rod-like Mn2O3with a mean size of similar to100～200nm. The as-prepared Mn2O3nanofibers were applied to construct an amperometric sensor for hydrazine detection in neutral phosphate buffer. As porous material is good for metal loading, we further prepared Mn2O3-Au composite material and it’s catalytic activity towards the oxidation of N2H4, found that the composite shows better property. The developed hydrazine sensor showed a fast response time (within5s), a wide linear range of2x10-6-1.3×10-3M, a high sensitivity of500muA mM-1cm-2, a good limit of detection of1μM (S/N=3). These results demonstrate that Mn2O3nanorods have great potential in the application of hydrazine detection.