Development Of Butyrylcholinesterase Assays Based On The Regulation Of Optical Properties On Nanomaterials

Butyrylcholinesterase?BChE?is a non-specific cholinesterase,which mainly presents in the liver and serum,can hydrolyze various choline substances.BChE plays an important role in the normal operation of biological functions.and its content in serum is often used as a clinical diadynamic criteria for a variety of liver diseases.The commonly used BChE detection method is the Ellman method in clinical,which has high sensitivity and fast analysis speed,but its anti-interference ability is low,and the detection result is easily affected by sulfhydryl molecules in the body.Scientists from all over the world have developed variety of strategies and methods to replace the Ellman method.However,in varying degrees,they have various problems such as being too dependent on large instruments,low sensitivity,slow analysis speed,and expensive detection reagents.In this paper,several BChE detection methods based on nanomaterials are proposed.By adjusting the optical properties of nanomaterials,specific recognition,sensitive signal output of BChE and quantitative detection of BChE are achieved,the anti-interference ability of the detection method,the actual sample and the possibility of clinical application were studied.The main research contents and results are as follows:?1?Using sulfur quantum dots?SQDs?as fluorescent molecules and polydopamine?PDA?polymerized with dopamine hydrochloride?DA?as quencher,the PDA's internal fluorescence of SQDs is used to establish a fluorescence detection method for BChE.Butylcholine was hydrolyzed by BChE to produce choline.The reducing property of choline inhibits the process of DA polymerization to generate PDA,thereby inhibiting the internal effect of PDA on SQDs.Further,based on the fluorescence intensity ratio of the system before and after BChE added,the quantitative detection of BChE was realized.Under the optimal conditions,the ratio of the fluorescence intensity to the concentration of BChE?0.01²5 U/L?showed a good linear relationship with a detection limit of 0.0069 U/L.In addition,this method has good selectivity for biomolecules such as inorganic salt ions and amino acids,the high concentrations of interferences will not affect the accuracy of the detection results.?2?A composite structure of SQDs/MnO₂ nanosheets?MnO₂ NS?was constructed,and a quantitative detection method of BChE was constructed based on the regulation of BChE hydrolysate to its fluorescence resonance energy transfer?FRET?efficiency.After the SQDs/MnO₂ NS composite structure was formed,the fluorescence of SQDs was quenched by MnO₂NS.Thiocholine produced by BChE catalyzes hydrolysis substrate reduce MnO₂ NS to Mn²⁺,causing decomposition of the composite structure and restoring the fluorescence of SQDs.It is a good linear relationship between the fluorescence intensity ratio and BChE in the two concentration ranges of 0.05¹0 U/L and 10⁵00 U/L,with the detection limit?LOD?was as low as 0.035 U/L.This method has strong anti-interference ability,can realize the detection of BChE in human serum,and avoids the interference of acetylcholinesterase?AChE?and glutathione?GSH?in the organism with similar structural properties.?3?Based on the photothermal regulation of the reaction products of cuprous oxide?Cu₂O?and sodium sulfide?NaHS?by BChE,a portable BChE detection method based on a thermometer was established.Cu₂O reacts with NaHS efficiently,and the product has strong photothermal effect.This reaction has a strong dependence on the solution pH.Using the changes of pH and photothermal effects which was brought by the product of BChE catalyzes substrate hydrolysis,based on the change of temperature difference??T-?T_B?for BChE quantitative detection.Under the optimal conditions,?T-?T_B has a good linear relationship with BChE concentration?100⁵00 U/L?,and the detection limit is 79.43 U/L.This method has excellent anti-interference ability,good specificity,and all the detection equipment are portable instruments,which is convenient for the on-site detection of BChE.