A Novelassay For Detecting Biomarkers Of Insulin In Diabetes Diagnosis And Treatment

Purpose:Insulin is an endogenous protein hormone secreted by pancreatic islet?cells in the pancreas.Insulin is an important biomarker for different types of diabetes,hypoglycemia syndrome,insulin beta cell tumor and pancreatitis,and it plays a vital role in the diagnosis and treatment of diseases.At present,the traditional methods,including radioimmunoassay,chemiluminescence immunoassay,and enzyme-linked immunosorbent assay,are widely used for insulin detection.However,these methods are expensive,long detection time,high technical requirements and complicated detection process.This study combines an electrochemical biosensing platform to establish a new method for insulin detection,which is highly efficient,sensitive,enzyme-free,label-free,and is expected to achieve insulin detection in diluted human serum samples.Methods:This study constructed an electrochemical immunsensor based on molybdenum disulfide nanosheets modified with gold nanoparticle?AuNP@MoS₂?andantibody-coupledDNA-triggered hybridization chain reaction?HCR?.It was based on the use of a glassy carb on electrode that was modified with MoS₂ nanosheets decorated with gold nanoparticle?AuNP?to immobilize a large amount of first antibody?Ab₁?.Following exposure to target insulin,secondary antibody?Ab₂?that was cross-linked to a DNA initiator strand?T₀?to form an Ab₂@T₀conjugate was added to undergo a sandwich immunoreaction.Subsequently,the long dsDNA concatemer was formed by a hybridization chain reaction between Ab₂@T₀ and auxiliary probes?H₁,H₂?.Finally,the electrochemical probe ruthenium?II?hexaammine was intercalated into the dsHCR products via electrostatic interaction between the anionic DNA phosphate backbones and the cationic probe.Results:The electrochemical response,best measured at a potential of-0.5 to 0.1 V at 50 mV s^-11 has a dynamic range that extends from 0.1 pmol L^-11 to 1 nmol L^-11 insulin,and the detection limit is as low as 50 fmol L^-1.In addition,when added the clinical actual blood samples into the insulin,the quantitative detection of insulin can still be completed,and it has certain anti-interference ability.The assay has good specificity,reproducibility and good stability.Conclusion:A sandwich-type of electrochemical immunoassay was described for the determination of insulin based on molybdenum disulfide nanosheets modified with gold nanoparticle?AuNP@MoS₂?and antibody-coupled DNA-triggered hybridization chain reaction?HCR?.The good performance of this assay is attributed to the large specific surface area of the AuNP@MoS₂ and the high amplification efficiency of the HCR.In addition,the immunoassay has the advantages of simplicity and sensitivity,and has been successfully applied to insulin detection in diluted human serum samples,which provides a new detection method for diabetes diagnosis technology and has important clinical significance.