Noble Metal Based Nanomaterials In The Application Of Colorimetric Sensing Analysis Of Acid Phosphatase Activity

Acid phosphatase?ACP?is a hydrolase that is widely present in various tissues,cells,and body fluids and participate in many physiological processes.As a serum marker of prostate cancer and other diseases,the monitoring of ACP activity is an important clinical indicator for early diagnosis of related diseases.Among the existing methods for measuring the activity of ACP,colorimetric method has attracted extensive attention from researchers because of their relatively convenient,fast and sensitive specificity,and without need expensive and complicated instruments.Untill now,the present colorimetric sensors for ACP activity monitoring are still limited.Therefore,the development of ACP colorimetric sensor with excellent performance is still a research hotspot for scientists.In this paper,we constructed two new platforms of ACP colormetric sensing and realized the determination of ACP activity in actual physiological samples based on intrinsic oxidase-like activity of Pd/Pt NWs and the change of surface plasmon resonance?SPR?of gold nanoparticles?Au NPs?,respectively.The thesis is carried out from the following two aspects.?1?It was found that the prepared palladium-platinum bimetallicalloy nanowires?Pd/Pt NWs?possessed good oxidase-like activity,which can catalyze the oxidation of organic substrates 3,3,5,5-tetramethylbenzidine?TMB?and 2,2-azino bis?3-ethylbenzth iazoline 6 sulfonic acid??ABTS?without the presence of H₂O₂.The catalytic activity of nanowires depended on the proportion of Pd-Pt,and the ratiois 1:3 of Pd/Pt NWs?denoted as Pd/Pt-1:3 NWs?is centified to possess the strongest activity.The control exprement indicated that their catalytic activity was mainly derived from the superoxide radical(O₂^·-)produced during the catalytic process.Acid phosphatase?ACP?can catalyze substrate2-phosphate l-ascorbic acid trisodium salt?AAP?hydrolysis to produce the reductant of ascorbic acid?AA?,which can effectively inhibite the oxidase-like activity of Pd/Pt-1:3NWs via consuming the O₂^·-,and reducing the oxidized TMB?ox TMB?.Based on this phenonmenon,we developed a new colorimetric sensing platform for detecting ACP activity.The experiment results showed that there was a good linear relationship between the absorbance of ox TMB and ACP activity in the range of 0.17-2.67 U·L^-1 and the limit of detection was 0.06 U·L^-1.In addition,this method has also been successfully applied to the determination of ACP activity in fetal bovine serum.The intrinsic specificity of enzymatic reaction makes this method have good selectivity and potential application in drug screening and clinical detection.?2?This work developed a new strategy for ACP colorimetric detection based on enzymatic reaction induced the generation of core-shell gold-silver nanoparticles?Au@Ag NPs?.ACP catalyzes the hydrolysis of AAP to produce the reductant AA,which can reduce Ag⁺and deposit on the surface of Au NPs to form Au@Ag NPs.The change in the size of nanoparticle caused a blue shift of SPR peak from 510 to 416 nm,which lead to a color change from light pink to golden.Based on this,we established a new method for the detection of ACP activity.Under the optimal experimental conditions,the changes of absorbance at 400 nm showed a good linear relationship with the ACP in two concentration ranges of 0.01-2 U·L^-1 and 2-16 U·L^-1 with the limit of detection was 0.01 U·L^-1.Compared with the previous ACP monochromatic colorimetry,the unique SPR peak migration will lead to a variety of color changes,which is of great significance to realize the sensitive detection of ACP visualization.In addition,it was successfully used to determine the ACP activity in fetal bovine serum with recovery rates of 96.9-102.4%.This method is simple,sensitive and maneuverable,and is expected to be popularized and applied in the future.