Controllable Preparation Of Rod-shaped β-FeOOH Nano-Peroxidase Mimics And Its Application In Immunochromatography

Immunochromatography assay(ICA)is a new,simple,fast,and home-based Point-of-care Testing(POCT)method.With the increasing demand for testing,ICA has been quickly promoted to the detection of proteins,pesticides,viruses,and pathogenic bacteria.Currently,the commercially available ICA test strips are mainly based on colloidal gold as the carrier,which is prone to shortcomings such as low sensitivity,false positives,and poor repeatability.Therefore,researchers have introduced nanomaterials with unique physical and chemical properties into ICA to improve the sensitivity of detection.On the one hand,nanomaterials have a large specific surface area,which can be fully combined with biomolecules to obtain higher detection sensitivity;on the other hand,some nanomaterials(Au,Pt,and other noble metals and iron-based materials)have characteristics similar to natural enzymes,which can catalyze the color reaction of organic substrates and amplifies the detection signal.Firstly,this article proposed a method for preparing rod-shaped β-FeOOH nano-peroxide mimetic enzymes by a simple low-temperature thermal hydrolysis method.The effect of reaction conditions on β-FeOOH was studied,and its morphology,composition,and dispersion were characterized.The results show that the β-FeOOH prepared in this paper presents a uniform rod-like structure,and its morphology and dispersion can be adjusted by changing the reaction conditions.The β-FeOOH nanorods prepared by this method have excellent stability and can exist stably in an aqueous solution.Secondly,this article discussed the enzyme catalytic conditions of β-FeOOH nanorods,and investigated the enzyme catalytic performance of β-FeOOH through Michaelis-Menten.The mechanism of its enzymatic catalysis was initially explored.The results show that β-FeOOH nanorods exhibit typical peroxidase-like activity,and the catalytic process satisfies the Michaelis-Menten model.In fact,the enzyme catalytic property of β-FeOOH is to catalyze the decomposition of H2O2 to produce a large amount of · OH,and then·OH oxidizes 3,3,5,5-tetramethylbenzidine(TMB)to produce blue-green ox-TMB.Through this process,the peroxidase-like catalytic effect is achieved.Finally,this article used rod-shaped β-FeOOH nano-peroxidase mimetic enzyme as a labeling material,combined with biomolecules as an immunoprobe,and applied to a lateral flow immunochromatographic detection system.β-FeOOH nanorods have the catalytic properties of a peroxidase mimicking enzyme,and can catalyze color development with TMB,which can significantly deepen the color of the detection strip,realize the amplification of the detection signal,improve the detection sensitivity,and achieve a low concentration of the sample detection.In this article,the rod-shaped β-FeOOH nano-peroxidase mimetic ICA has a great detection effect on human chorionic gonadotropin(HCG),and the detection limit is 25 mIU/mL.After dropping the chromogenic reagent on the NC membrane,the β-FeOOH nanozyme on the detection line catalyzes the color reaction of the substrate,which realizes the enhancement of the band detection signal,the detection limit can reach 15 mIU/mL,and the detection sensitivity is increased by 1.67 Times,it is expected to be used for the detection of clinical samples.