Research On Paper Chip In The Detection Of Microcystin-LR And Its Effect-biomarkers

With the increasing pollution of the water environment,low concentration of phytotoxins in water are difficult to degrade.After entering the food chain,bioaccumulation and biomagnification of phytotoxins will cause the change of cytokine level and carcinogenesis of the body,which will lead to cancer in turn.In this process,the effect-biomarkers are the key cytokine that reveal the occurrence of malignant tumors,meanwhile,phytotoxins are the direct factor.Therefore,it is of great significance to develop new techniques and methods in realizing fast,simple and inexpensive analysis of phytotoxins and their effect-biomarkers,and it is also important for the development of toxicology.Paper chips have been rapidly developed in many fields due to their low cost,simple and fast characteristics.In this paper,two different detection devices are designed to meet high sensitive and rapid detection of phytotoxins and effect-biomarkers.Several works are as follow:(1)A foldable paper chip was designed to achieve quantitative detection of microcystin-LR,and the chip separated the reaction well from the coloring well.Using the principle of direct competition enzyme-linked immunosorbent assay,the antibody was coated on the paper chip.The antigen in the sample competed with the enzyme-labeled antigen for the immobilized antibody.The antigen was preferentially captured by the immobilized antibody,while the enzyme-labeled antigen was captured by the excess antibody.After washing the reaction well,folded up the coloring well to align the flow channels that free enzyme-labeled antigen can flow into the signal coloring well with the washing solution.The signal of the coloring well was proportional to the antigen concentration in the sample after adding the enzyme substrate solution.This method achieved sensitive detection of microcystin-LR with a detection limit of 0.1 ?g/L,which met the drinking water standard(1 ?g/L)set by the World Health Organization(WHO).(2)An analytical device based on paper chips and aptamers was prepared to achieve quantitative detection of PDGF.A more stable circular aptamer was selected to recognize the target protein molecule-PDGF,which can resist the hydrolysis of exonuclease in serum.When the sample did not contain PDGF,the circular aptamer was adsorbed on the surface of graphene oxide,and there was no free aptamer in the supernatant after centrifugation,so that the nucleic acid amplification reaction cannot be performed on the paper chip.When PDGF was present,the circular aptamer bound to the target molecule and it was released from the surface of graphene oxide,which in turn can trigger the nucleic acid amplification reaction on the paper chip.High sensitivity quantitative detection of PDGF was achieved through color change,with a minimum detection limit of 100 pM.