A novel framework-targeted affinity-based sandwich photoelectrochemical sensor for trace acrylamide determination.

Acrylamide (AAm), a carcinogenic by-product formed during food processing, presents significant health concerns. Here, we developed an innovative photoelectrochemical (PEC) sensor for ultra-sensitive AAm detection, based on a framework-targeted affinity strategy. Utilizing a metal-coordinated porphyrin-based covalent organic framework (TT-Por(Co)-COF) as the capture layer, the sensor leverages thiophene units to enhance charge transport and selectively adsorb AAm. Independent Gradient Model (IGMH) analysis confirmed two weak interaction regions, predominantly hydrogen bonding and van der Waals forces, between AAm and the TT units. Signal amplification is achieved using CdTe quantum dots functionalized with an AAm-specific aptamer. Upon AAm binding, the aptamer facilitates QD accumulation, significantly enhancing photocurrent for precise quantification. Under optimized conditions, the sensor exhibited excellent analytical performance with a linear range from 1 pM to 1000 nM and a detection limit of 0.19 pM (3σ/S, n = 11). offering a promising solution for real-time food safety monitoring.