Epitaxial Self-Assembly of Interfaces of 2D Metal–Organic Frameworks for Electroanalytical Detection of Neurotransmitters

Abstract

This paper identifies the electrochemical properties of individual facets of anisotropic layered conductive metal–organic frameworks (MOFs) based on M 3 (2,3,6,7,10,11-hexahydroxytriphenylene) 2 (M 3 (HHTP) 2 ) (M = Co, Ni). The electroanalytical advantages of each facet are then applied toward the electrochemical detection of neurochemicals. By employing epitaxially controlled deposition of M 3 (HHTP) 2 MOFs on electrodes, the contribution of the basal plane ({001} facets) and edge sites ({100} facets) of these MOFs can be individually determined using electrochemical characterization techniques. Despite having a lower observed heterogeneous electron transfer rate constant, the {001} facets of the M 3 (HHTP) 2 systems prove more selective and sensitive for the detection of dopamine than the {100} facets of the same MOF, with the limit of detection (LOD) of 9.9 ± 2 nM in phosphate-buffered saline and 214 ± 48 nM in a simulated cerebrospinal fluid. Langmuir isotherm studies accompanied by all-atom MD simulations suggested that the observed improvement in performance and selectivity is related to the adsorption characteristics of analytes on the basal plane versus edge sites of the MOF interfaces. This work establishes that the distinct crystallographic facets of 2D MOFs can be used to control the fundamental interactions between analyte and electrode, leading to tunable electrochemical properties by controlling their preferential orientation through self-assembly.

Controllable Construction of Two-Dimensional Conductive M3(HHTP)2 Nanorods for Electrochemical Sensing of Malachite Green in Fish

“…In the X-ray powder diffraction (XRD) experiment, 2θ of the diffraction peaks was located at ≈4.8°, ≈9.6°, ≈12.7°, and ≈28°, respectively, corresponding to the (100), ( 200), (210), and (001) planes, 9,11,40,45,46 as shown in Figures 2A and S2. The hk 0 reflection in XRD experiments, 40 especially in the region of about 2θ ≈ 26°, was relatively sharp.…”

“…In the X-ray powder diffraction (XRD) experiment, 2θ of the diffraction peaks was located at ≈4.8°, ≈9.6°, ≈12.7°, and ≈28°, respectively, corresponding to the (100), ( 200), (210), and (001) planes, 9,11,40,45,46 as shown in Figures 2A and S2.…”

Defective Metal–Organic Framework Nanocrystals as Signal Amplifiers for Electrochemical Dopamine Sensing

“…Because of the high surface area of MOFs, several previous studies have demonstrated the direct use of water-stable MOFs as the active materials for electrochemical DA detection. − For example, Mirica et al demonstrated the use of two-dimensional conductive MOFs for electrochemical DA detection . Wu and coworkers reported one of the first attempts at the use of the highly porous and water-stable Zr-MOFs in electrochemical DA sensors .…”

In situ engineering of Au–Ag alloy embedded PEDOT nanohybrids at a solvent/non-solvent interface for the electrochemical enzyme-free detection of histamine

“…14 Electrochemical sensing parameters have improved with the evolution from naturally occurring graphitic materials to synthetic materials such as conducting polymers, MXenes, and metal alloy nanoparticles (NPs). [14][15][16][17] Research on conducting polymers (CPs), particularly PEDOT, has seen tremendous strides owing to their intrinsic advantages of high electrical conductivity, optical transparency, low redox potential, high environmental stability, and biocompatibility. [18][19][20] Chemical polymerization using oxidizing agents or electro-polymerization, using a potential applied across a monomer solution, are the two frequently exploited methods for the effectual nanostructure tuning of CPs.…”