Atomic-layer-deposited MoS₂@TaS₂ nano-heterojunctions for dual-active quantum dot photoelectrochemical biosensing of nucleolin

Early cancer diagnosis remains a global challenge due to the lack of ultrasensitive and specific detection methods. Herein, we report a dual-active quantum dots (QDs) photoelectrochemical (PEC) sensing platform based on a MoS₂@TaS₂ nano-heterojunction engineered via atomic layer deposition (ALD) for the detection of nucleolin (NCL), a key cancer biomarker. The petal-like MoS₂@TaS₂ nanosheets exhibit enhanced light-harvesting and charge transport properties, as well as a high surface area for uniform QDs loading. This architecture promotes efficient charge separation and suppresses recombination through the synergistic interaction between the heterojunction and CdTe QDs. The resulting sensor achieves a wide linear range (1 fM to 1 nM) and an ultralow detection limit of 0.65 fM, along with excellent specificity and stability. This work offers a promising PEC strategy for early cancer diagnosis.