Single-atom nanozymes(SANs)possess unique features of maximum atomic utilization and present highly assembled enzyme-like structure and remarkable enzyme-like activity.By introducing SANs into immunoassay,limitations ...Single-atom nanozymes(SANs)possess unique features of maximum atomic utilization and present highly assembled enzyme-like structure and remarkable enzyme-like activity.By introducing SANs into immunoassay,limitations of ELISA such as low stability of horseradish peroxidase(HRP)can be well addressed,thereby improving the performance of the immunoassays.In this work,we have developed novel Fe-N-C single-atom nanozymes(Fe-N_(x)SANs)derived from Fe-doped polypyrrole(PPy)nanotube and substituted the enzymes in ELISA kit for enhancing the detection sensitivity of amyloid beta 1-40.Results indicate that the Fe-N_(x)SANs contain high density of single-atom active sites and comparable enzyme-like properties as HRP,owing to the maximized utilization of Fe atoms and their abundant active sites,which could mimic natural metalloproteases structures.Further designed SAN-linked immunosorbent assay(SAN-LISA)demonstrates the ultralow limit of detection(LOD)of 0.88 pg/mL,much more sensitive than that of commercial ELISA(9.98 pg/mL).The results confirm that the Fe-N_(x)SANs can serve as a satisfactory replacement of enzyme labels,which show great potential as an ultrasensitive colorimetric immunoassay.展开更多
Developing reliable and facile approaches for alkaline phosphatase(ALP)sensing is important due to its role as a clinical biomarker for many diseases.In this study,we proposed a new and convenient colorimetric assay b...Developing reliable and facile approaches for alkaline phosphatase(ALP)sensing is important due to its role as a clinical biomarker for many diseases.In this study,we proposed a new and convenient colorimetric assay based on the pyrophosphate(PPi)-mediated oxidase-mimicking activity switching of nanosized MnFe_(2)O_(4) for the detection of ALP.The synthesized MnFe_(2)O_(4) exhibited high oxidase-like activity to catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine(TMB)to its blue product TMBox in the presence of dissolved O2,leading to a color reaction rapidly and remarkably;PPi could significantly inhibit the activity of the MnFe_(2)O_(4) nanozyme via the strong interaction between PPi and the Fe(III)species in MnFe_(2)O_(4),resulting in the suppression of the TMB color reaction;when ALP was added,it hydrolyzed the PPi substrate to phosphate(Pi)that had no obvious effect on the MnFe_(2)O_(4) activity,and such that the TMB color reaction catalyzed by the nanozyme could be observed again.With the above principle,linear colorimetric determination of ALP in the scope of 0.6-55 U L−1 was achieved,giving the limit of detection down to 0.27 U L−1.Besides,the developed assay could provide selective response toward ALP against other co-existing biological species.Furthermore,reliable detection of ALP in human serum samples was verified by our assay,revealing its great promise as an effective and facile tool for ALP monitoring in clinical practice.展开更多
基金This work was supported by a start-up fund from Washington State University.
文摘Single-atom nanozymes(SANs)possess unique features of maximum atomic utilization and present highly assembled enzyme-like structure and remarkable enzyme-like activity.By introducing SANs into immunoassay,limitations of ELISA such as low stability of horseradish peroxidase(HRP)can be well addressed,thereby improving the performance of the immunoassays.In this work,we have developed novel Fe-N-C single-atom nanozymes(Fe-N_(x)SANs)derived from Fe-doped polypyrrole(PPy)nanotube and substituted the enzymes in ELISA kit for enhancing the detection sensitivity of amyloid beta 1-40.Results indicate that the Fe-N_(x)SANs contain high density of single-atom active sites and comparable enzyme-like properties as HRP,owing to the maximized utilization of Fe atoms and their abundant active sites,which could mimic natural metalloproteases structures.Further designed SAN-linked immunosorbent assay(SAN-LISA)demonstrates the ultralow limit of detection(LOD)of 0.88 pg/mL,much more sensitive than that of commercial ELISA(9.98 pg/mL).The results confirm that the Fe-N_(x)SANs can serve as a satisfactory replacement of enzyme labels,which show great potential as an ultrasensitive colorimetric immunoassay.
基金This study was supported by the National Natural Science Foundation of China(21605061 and 31601549)the Natural Science Foundation of Jiangsu Province(BK20160489)+1 种基金the Open Fund from the Shanghai Key Laboratory of Functional Materials Chemistry(SKLFMC201601)the Cultivation Project for Excellent Young Teachers in Jiangsu University.
文摘Developing reliable and facile approaches for alkaline phosphatase(ALP)sensing is important due to its role as a clinical biomarker for many diseases.In this study,we proposed a new and convenient colorimetric assay based on the pyrophosphate(PPi)-mediated oxidase-mimicking activity switching of nanosized MnFe_(2)O_(4) for the detection of ALP.The synthesized MnFe_(2)O_(4) exhibited high oxidase-like activity to catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine(TMB)to its blue product TMBox in the presence of dissolved O2,leading to a color reaction rapidly and remarkably;PPi could significantly inhibit the activity of the MnFe_(2)O_(4) nanozyme via the strong interaction between PPi and the Fe(III)species in MnFe_(2)O_(4),resulting in the suppression of the TMB color reaction;when ALP was added,it hydrolyzed the PPi substrate to phosphate(Pi)that had no obvious effect on the MnFe_(2)O_(4) activity,and such that the TMB color reaction catalyzed by the nanozyme could be observed again.With the above principle,linear colorimetric determination of ALP in the scope of 0.6-55 U L−1 was achieved,giving the limit of detection down to 0.27 U L−1.Besides,the developed assay could provide selective response toward ALP against other co-existing biological species.Furthermore,reliable detection of ALP in human serum samples was verified by our assay,revealing its great promise as an effective and facile tool for ALP monitoring in clinical practice.
