Tumor necrosis factor-alpha(TNF-α) is a type of critical pro-inflammatory cytokines,which participates in numerous cellular signal pathways and is regarded as a critical protein biomarker for inflammatory based diseases.In this contribution,we have developed a strategy to fabricate multiple DNA star trigon structures with fluorescence signals from four hairpin probes which are detonated by a single molecule of TNF-α.This process causes significant enhancement of fluorescence and a sensitive and selective biosensor for TNF-α assay is constructed.This method is able to achieve the limit of detection(LOD) at 5 pg/mL(0.285 pM).Moreover,some other advantages such as fast response,high selectivity and convenient operation promise the potential use of this method for TNF-α measurement in point of care testing application.Upon further development,this strategy can also be converted to detect other analytes such as small molecules,nucleic acids and other proteins. Tumor necrosis factor-alpha (TNF-α) is a type of critical pro-inflammatory cytokines, which participates in numerous cellular signal pathways and is regarded as a critical protein biomarker for inflammatory-based diseases. In this contribution, we have developed a strategy to fabricate multiple DNA star trigon structures with fluorescence signals from four hairpin probes which are detonated by a single molecule of TNF-α. This process causes significant enhancement of fluorescence and a sensitive and selective biosensor for TNF-α assay is constructed. This method is capable to achieve the limit of detection (LOD) at 5 pg / mL (0.285 pM). Moreover, some other advantages such as fast response, high selectivity and convenient operation promise the potential use of this method for TNF-α measurement in point of care testing application.Upon further development, this strategy can also be converted to detect other analytes such as small molecules, nucleic acids and other proteins.