Construction And Application Of Colorimetric Sensors Based On Molybdenum Disulfide Nanocomposites

Colorimetric detection has the advantages of simple operation,low detection cost,high sensitivity,good selectivity and no need for any expensive or complicated instruments,which can be widely applied in fast detectionand on-site inspection requirements as well as for the remote areas with relatively backward conditions without large instruments.Nowadays,colorimetric sensors have been widely used in research fields such as environmental monitoring,molecular recognition and biomedical diagnostics,having become an important tool for analytical testing.The introduction of nanomaterials can effectively improve the analytical performance and detection stability of colorimetric sensors.Molybdenum disulfide has been successfully used in the construction of biosensors due to its unique structural characteristics and excellent physicochemical properties.In this paper,combining the superior catalytic activity of molybdenum disulfide nanocomposites with colorimetric sensing strategy,colorimetric sensors were constructed for the detection of biomolecules with high sensitivity and specificity.The specific works of this paper is as follows:1.A colorimetric immunobiosensor based on molybdenum disulfide nanocomposites was constructed for highly sensitive detection of carcinoembryonic antigen?CEA?.Gold nanoparticle-loaded MoS₂ nanocomposites?MoS₂-AuNPs?with excellent catalytic activity were prepared.CEA specific antibody?anti-CEA?were assembled onto the surface of MoS₂-based nanocomposite to construct two kinds of nanoprobes.Due to the adsorption of anti-CEA,the catalytic activity of MoS₂-AuNPs was slightly decreased,but it still had good catalytic performance for colorimetric reaction.The two nanoprobes formed a classic"sandwich"immune complex with the addition of CEA.After centrifugation and catalytic reaction,we can achieve qualitative and quantitative detection of CEA by visually observing the color change of the solution.In this detection strategy,the signal response of the colorimetric sensor at 400 nm was linear with the logarithm of concentration with CEA in the range of 5 pg mL^-1-10 ng mL^-1,and the detection limit was as low as 0.5 pg mL^-1.In addition,the sensor had excellent selectivity and stability,which can effectively distinguish CEA and other proteins,as well as obtain good detection results in human serum.2.A colorimetric sensing strategy based on molybdenum disulfide nanocomposites for rapid and sensitive detection of amino acids was designed.The gold-platinum core-shell bimetallic nanoparticle-modified molybdenum disulfide nanocomposites?MoS₂-Au@Pt NPs?were synthesized and it was used to colorimetricly detect cysteine?Cys?due to its exceptional peroxide mimic enzyme activity.MoS₂-Au@Pt NPs can catalyze H₂O₂-TMB detection system with the color change from colorless to blue.After the addition of H₂SO₄,a significant UV-vis absorption peak was generated at450 nm.Under optimal conditions,the absorbance intensity at 450 nm shown a linear relationship with the concentration of Cys ranging from 0.8?M to 54.4?M in the colorimetric sensor.The colorimetric sensor showed low detection limit of 0.5?M and it can effectively distinguish the other19 amino acids and its metabolite cystine.In addition,this sensor could evalyate the content of cysteine in the cysteine supplement,which had practical detection significance.