Ultra-sensitive label-free DNA detection based on n-type accumulation mode vertical organic electrochemical transistors

Herein, we present an ultrasensitive DNA detection platform based on n-type accumulation-mode vertical organic electrochemical transistors (vOECTs) for the first time. The vOECTs utilize poly(benzimidazobenzophenanthroline) (BBL) as the n-type organic semiconductor channel, operating in accumulation mode with low power consumption and ultrahigh transconductance (up to 53.7 mS). DNA probes were immobilized on Au gate electrodes via Au–S bonds, followed by 6-mercapto-1-hexanol (MCH) blocking to minimize nonspecific adsorption. Target DNA hybridization induces interfacial charge redistribution and electrical double-layer (EDL) modulation, amplifying current responses through the vOECT's high transconductance. The platform achieves an exceptional sensitivity of 155.91 μA/dec—31-fold higher than state-of-the-art DNA sensors—and an ultralow detection limit of 1.07 aM. Notably, the sensor enables label-free, amplification-free detection with rapid response and excellent stability. This work establishes a novel approach for high-precision nucleic acid analysis in biomedical applications.