The Study Of Optical Enzymatic Glucose And Hydrogen Peroxide Nanosensors

Glucose and hydrogen peroxide detection plays an important role in controlling various food and biotechnological processes as well as in diagnosing many metabolic disorders. Enzymatic reaction has features of specific and fast responding speed. Oxygen, which can quench luminescence molecules, was involved in glucose and hydrogen peroxide enzymatic reaction. Thus, the change of oxygen content can directly reflect the concentration of glucose and hydrogen peroxide. Meantime, optical detection measures have advantages of short response time and noninvasive. Herein, the concentration of glucose and hydrogen peroxide can be measured via oxygen probe molecule.Based on the optical feature of Pt(Ⅱ)-meso-tetra(pentafluorophenyl)porphine (PtTFPP), this paper adopts glucose oxidase (GOx) and horse radish peroxidase (HRP) as modified molecular to respective prepare glucose and hydrogen peroxide biosensor. The main task of this research are:1. The glucose nanosensor was facilely prepared by coupling GOx with poly-1-lysine coated oxygen nanosensors via a glutaraldehyde-mediated Schiff-base reaction. The GOx molecules residing on particle surface catalyzed glucose with the expense of oxygen. Under the optimized experimental conditions, the calibration was performed with two modes, namely ratiometric photoluminescence and time-resolved fluorescence (TRF). Under the former mode, the dynamic range was 2-10 mM and the limit dection was 1-2 mM. While under the later mode, the number was 1-6 mM and 0.1-0.2 mM. This biosensor also has been tested in human serum sample for the detection of glucose.2. Fluorescence hydrogen peroxide biosensor was prepared via improved one-step reprecipitation-encapsulation method. The HRP molecules were placed on the surface of the nanosensor, which can catalyzed hydrogen peroxide and produce oxygen. The calibration was performed with two modes just like the former glucose biosensor. The dynamic range was 0.1-2 μM (under ratiometric photoluminescence mode) and 0.1-3 μM (under TRF mode). The limit detection was 0.34 and 0.067 μM.In this work, two types of biosensor were built which have good character via enzymatic reaction and oxygen probe PtTFPP. The glucose biosensor was used to detect human serum samples. The obtained results have some reference for building in vivo fluorescence biosensors, which can monitor concentration in real time.