Interfacial Self‐assembly of Chiral Selenide Nanomembrane for Enantiospecific Recognition

Abstract Here, we report the synthesis of chiral selenium nanoparticles (NPs) using cysteine and the interfacial assembly strategy to generate a self‐assembled nanomembrane on a large‐scale with controllable morphology and handedness. The selenide (Se) NPs exhibited circular dichroism (CD) bands in the ultraviolet and visible region with a maximum intensity of 39.96 mdeg at 388 nm and optical anisotropy factors (g‐factors) of up to 0.0013 while a self‐assembled monolayer nanomembrane exhibited symmetrical CD approaching 72.8 mdeg at 391 nm and g‐factors up to 0.0034. Analysis showed that a photocurrent of 20.97±1.55 nA was generated by the D‐nanomembrane when irradiated under light while the L‐nanomembrane generated a photocurrent of 20.58±1.36 nA. Owing to the asymmetric intensity of the photocurrent with respect to the handedness of the nanomembrane, an ultrasensitive recognition of enantioselective kynurenine (Kyn) was achieved by the ten‐layer (10L) D‐nanomembrane exhibiting a photocurrent for L‐kynurenine (L‐Kyn) that was 8.64‐fold lower than that of D‐Kyn, with a limit of detection (LOD) of 0.0074 nM for the L‐Kyn, which was attributed to stronger affinity between L‐Kyn and D‐Se NPs. Noticeably, the chiral Se nanomembrane precisely distinguished L‐Kyn in serum and cerebrospinal fluid samples from Alzheimer's disease patients and healthy subjects.