Nano-graphite aptasensor combined with enzyme signal amplification for the detection of alpha-fetoprotein
The tumor marker alpha-fetoprotein(AFP)was detected using a graphite-aptamer sensor combined with DNase I signal amplification strategy.A novel fluorescence sensor,NG/Aptamer,was synthesized by incorporating nano-graphite(NG)and DNase I into the aptamer solution.Following the addition of AFP,the formation of the AFP/aptamer complex led to the dissociation of the aptamer from the NG surface.The aptamer was then degraded by DNase I,releasing the target AFP for a new cycle,resulting in a significant amplification of the detection signal.Under optimal conditions,the AFP concentration within the range of 3~150 pg·mL-1 exhibited a linear relationship with fluorescence intensity.The detection limit was established at 2.556 pg·mL-1.Further-more,the developed sensors demonstrated high specificity for AFP,with no interference from other structurally similar substances.The sensor was also applicable for AFP detection in human serum samples,achieving a recovery rate between 95.1%and 103.8%.