Label?free and Sensitive Detection of Biothiols Using a Turn?on Fluorescent Nanoprobe Based on Protein?templated Gold Nanoclusters Coupled with Cobalt Oxyhydroxide Nanoflakes

KeyWord:fluorescent nanoprobe  CoOOH nanoflakes  protein£­CoOOH interaction  protein?templated gold nanoclusters  label?free  biothiols

Abstract:

      Cobalt oxyhydroxide£¨CoOOH£©nanoflakes£¬an emerging and promising functional two?dimensional£¨2D£©nanomaterial with remarkable physical and chemical properties£¬have received much attention in recent years.Until now£¬all kinds of fluorescent nanoprobes by integrating CoOOH nanoflakes with fluorescent inorganic nanomaterials have been reported.However£¬the synthesis procedures for fluorescent inorganic nanomaterials employed in these nanoprobes are generally time?consuming and complex£¬and most of them are limited to sensing ascorbic acid. Therefore£¬investigation on the interaction between CoOOH nanoflakes and biomolecule£¬and the development of new CoOOH?based fluorescent nanoprobe to broaden biological applications is very interesting and also of great importance.Herein£¬a turn?on fluorescent nanoprobe based on CoOOH nanoflakes and BSA?templated gold nanoclusters£¨BSA@AuNCs£©was constructed for sensitive and label?free detection of biothiols.It was found that negative BSA@AuNCs were easily and effectively assemblied on the surface of positive CoOOH nanoflakes to construct a BSA@AuNCs£­CoOOH nanoprobe in a short time through the electrostatic interaction between scaffold protein BSA and CoOOH nanoflakes.As a result£¬the red strong fluorescence emitted by BSA@AuNCs could be efficiently quenched by CoOOH nanoflakes through inner?filter effect£¨IFE£©.The CoOOH nanoflakes in the BSA@AuNCs£­CoOOH nanoprobe were degraded in the presence of the target biothiol due to the specific redox reaction between biothiols and CoOOH nanoflakes£¬leading to the release and fluorescence recovery of [e-mail] the basis of the emission increase of BSA@AuNCs£¬a robust fluorescence sensing strategy for sensitive and selective detection of biothiols was developed£¬which was demonstrated to be suitable for the quantitative analysis of biothiols£¨Cys£¬GSH and Hcy£©in the range of 0.?05£­150 ¦Ìmol/L£¬with a detection limit as low as 30 nmol/L.Furthermore£¬this nanoprobe exhibited a high selectivity towards biothiols other than amino acids£¬metal ions and saccharides.The practical application of this nanoprobe was verified£¬and it was successfully applied to the detection of biothiol£¨Cys£©in human serum samples.The developed biosensing strategy might provide a simple£¬facile£¬cost?efficient and rapid platform for biothiols?related clinical disease diagnosis.