(619d) Magnetic Nanoparticles/Glucose Oxidase Mediated Cascade Catalysis for Cancer Marker Rapid Detection

Many technologies have been developed for rapid detection of cancer marker, such as typical ELISA, biochips and novel nanobiosensors. These technologies always take many steps, for example, antigen/antibody binding and washing step by step, which will take long time and make the test become burdensome. So it is imperative to develop novel detection system for rapid diagnosis of disease, especially for point of care or home test. Here we reported a novel method for cancer marker detection based on cascade enzymatic activity of magnetic nanoparticles and glucose oxidase. Our previous work found that magnetic nanoparticles have peroxidase like catalysis and catalyze color reaction in H2O2/TMB system which is usually used in ELISA. The fundmental strategy is to combine catalytic magnetic nanoparticles and glucose oxidase which can produce H2O2 by catalyzing glucose. The mechanism is that adjacent effect between magnetic nanoarticles and glucose oxidase accelerates the color reaction, which means that magnetic nanoparticles mixed with glucose oxidase can perform color reaction only when there is an intermediate that can connects two moieties together. Cancer marker CA125 hase been tested by this method. Two CA125 specific antibodies are crosslinked onto magnetic nanoparticles and glucose oxidase repecitively. For the detection we just need to mix CA125 with antibody coupled magnetic nanoparticles and glucose oxidase at one-step. The color signal produced by cascade catalysis showed clear relation with the concentration of CA125, which means the new system can be used to rapidly detect cancer marker. The system has two advantages compared to classic bioassay. One is that it is very simple and just need to mix the antigen into reaction buffer, which especially suits for point of care or home test. The other is that the reaction is fast because the binding between antigen and antibody is achieved in homogenous liquid phase. The new method has promising potential in rapid diagnosis for cancer markers and other diseases.