DFT insights into assembling [8]MCPP with [14]pyridine nanobelts for amino acid sensing.

The progress in designing nanoscale electronic sensors for detecting amino acids (AAs) has attracted considerable interest due to their ability to enable label-free and real-time detection. In this study, the [14]pyridine@[8]MCPP system formed by assembling [8]cycloparaphenylene ([8]MCPP) with [14]pyridine methylene-bridged nanobelts was investigated using density functional theory (DFT) calculations as a potential sensor for five amino acids: glycine (Gly), alanine (Ala), threonine (Thr), leucine (Leu), and aspartic acid (Asp). The sensing capabilities of the assembled structure were evaluated through various analyses, including frontier molecular orbital (FMO), density of states (DOS), quantum theory of atoms in molecules (QTAIM), non-covalent interactions (NCI), and electron density difference (EDD). The energy gap of the [14]pyridine@[8]MCPP assembly was influenced by the presence of amino acids, with the most significant change (-8.75 %) observed in the [14]pyridine@[8]MCPP/Asp complex. Furthermore, QTAIM and NCI analyses indicated that the interactions between AAs and the [14]pyridine@[8]MCPP assembly are primarily governed by van der Waals (vdW) forces. The short recovery times (3.47 × 10 to 1.27 × 10 s) and favorable sensor responses (0.09-0.17) of the [14]pyridine@[8]MCPP/AA complexes at 298 K suggest that this assembly could serve as an effective material for detecting amino acids. These findings underscore the potential of assembled nanostructures as valuable candidates for amino acid sensing applications.