Nanozyme Inhibited Sensor Array For Biothiols Detection And Disease Discrimination Based On Metal Ion-Doped Carbon Dots

Biothiol is a thiol-containing amino acid or oligopeptide,the most typical of which are Cys,GSH and Hcy.Biothiols are important components of many proteins and biologically active small molecules that maintain redox homeostasis in biological systems.Alterations in intracellular biothiol levels may be a harbinger of many underlying diseases such as common hypertension,Alzheimer’s disease,and recalcitrant diseases such as cancer.Therefore,the detection of biothiols is closely related to human physiological health,and it is important to develop a new method for biothiol detection that is simple,sensitive and selective.Although today’s detection methods such as HPLC and fluorescence are technically mature,they are complicated and expensive for rapid detection,while colorimetric methods are of great interest because of their simplicity,practicality and low cost.However,considering the limitations of traditional colorimetric methods such as single parameter analysis,the high-throughput and high-sensitivity identification of biological thiols is still a great challenge.By mimicking the gustatory or olfactory systems of mammals,array-based sensing approaches are effective means for the simultaneous determination and differentiation of multiple analytes.The sensor array consists of different cross-responsive sensing elements to produce a composite response for the detection and identification of various targets,which compensates for the short comings of the old methods while achieving portability and diversity,and is expected to make the realization of the above objectives possible.The combination of the surface function alactivity of carbon quantum dots and the catalytic function of metal ions can form stable and efficient and diverse metal-carbon dot nanozymes to construct an array,which use the interaction between biological thiols and the matrix of sensing units to induce color development reactions to produce color changes to ouput multiple signal arrays for fast and sensitive and high throughput detection.This paper presents a series of studies based on the construction and application of a colorimetric array sensor for biothiols detection,including:the design and synthesis of two metal ion-doped carbon dots and verification of their excellent peroxidase-like activity;the assembly of the array sensor and successful identification of three biothiols standards;and the identification and diagnostic study of biomedical samples.Specific findings are as follows:1.Metal(Cu²⁺/Fe³⁺)doped CDs were prepared in situ by a simple one-step microwave carbonization method with magnetic stirring assisted microwave method using citric acid-metal salts-ethylenediamine as raw materials;the morphology,structure,stability,peroxidase activity,metal content and catalytic mechanism of the products were characterized to verify the successful synthesis of metal-doped carbon dots（M-CDs）and their excellent peroxidase-like properties.2.To investigate the effect of biothiols.on the peroxidase properties of metal-doped CDs,a colorimetric array sensor was constructed using the metal-doped CDs-TMB-H₂O₂system with both color change and cross-responsiveness.Low concentrations of standard solutions of biothiols were accurately distinguished by pattern recognition methods（HCA and PCA）with a detection limit of 5n M.In addition,the identification of single biothiols and mixtures of biothiols at various concentrations was achieved.3.Based on the high-precision differentiation of mixed thiol samples,we have further identified biomedical samples with more complex composition.By studying the cytoplasmic characteristics of tumor cells,accurate discrimination was made between normal cells（HEK293）and lysates of three types of tumor cells,MCF-7,HK-2,and K150;data information was obtained by collecting serum samples from patients with cardiovascular diseases,and a sensor array was used to classify people at various health levels based on the preliminary diagnosis of sera with different indicators.