An Eu4L44 tetrahedron with multiple recognition sites: a luminescent sensor for rapid and sensitive detection of biogenic amines

Abstract

Biogenic amines are important bioactive substances in living organisms, and their abnormal metabolism can serve as biomarkers for certain diseases such as depression, Parkinson's disease and transient tic disorder. Therefore, developing a highly efficient and sensitive luminescent sensor for biogenic amines is essential. However, the biological system is a complex liquid environment containing multiple active substances, which can reduce effective collisions between the sensor and the target analyte, thereby diminishing the sensor's sensitivity. To address this issue, we introduced reaction sites that can undergo nucleophilic and hydrogen bonding interactions with amino groups into the structure of the sensor, and designed and synthesized a multi-site tetrahedral cage Eu₄L⁴₄ to achieve specific capture of biogenic amines. By leveraging these dual interactions between Eu₄L⁴₄ and amines, combined with the confined cavity effect of the cage, multiple spectroscopic analyses demonstrated that the detection limit for ethylenediamine (EDA) improved from 370 μM (Eu₄L¹₄) to 33 μM (Eu₄L⁴₄), while the response time decreased from 1.1 seconds to 0.81 seconds. This design provides an effective strategy for enhancing sensor sensitivity and paves the way for its application in detecting biogenic amines within biological systems.