A Turn-on Fluorescence Aptasensor Based On Carbon Dots For Sensitive Detection Of Adenosine

Adenosine,an endogenous nucleoside,has received intense attention due to its multiple important functions related to the physiology of the heart and brain.At the same time,it was consensually identified as a major local regulator of tissue function and honored as a ‘‘retaliatory metabolite’’ for its ability to equalize energy intake to metabolic demand.Recently,adenosine was found to provide a possible link with cancer and it has been reported as a biomarker for monitoring the progress of lung cancer.Hence,accurate detection and quantification of adenosine is of great significance.In this paper,a novel turn-on fluorescence aptasensor was designed for adenosine detection based on fluorescence resonance energy transfer(FRET)from single-stranded DNA labeled carbon dots(ss DNA-CDs)to aptamer modified gold nanoparticles(aptamer-Au NPs).In the absence of adenosine,the fluorescence of ss DNA-CDs was quenched by aptamer-Au NPs via the formation of an aptamer-ss DNA duplex.The introduced adenosine competed to displace ss DNA-CDs by specifically binding to the aptamer,resulting in the recovery of the quenched fluorescence of ss DNA-CDs.Under optimized conditions,the increase in fluorescence intensity was proportional to the concentration of adenosine with a linear range of 10-500 n M and allowed a limit of detection as low as 4.2 n M.In addition,this method was successfully applied to adenosine determination in human serum samples with satisfactory results.