A programmable Y-shaped junction scaffold-mediated modular and cascade amplification strategy for the one-step, isothermal and ultrasensitive detection of target DNA.The programmable DNA polymerization across the two branches of the assembled Y-shaped junction was ingeniously manipulated for modular target recycling and cascade lambda exonuclease cleavage, which afforded the one-pot, isothermal and ultrasensitive detection of target DNA. 
THERM