Recognition Of Enantiomers Research Articles

Chemoselective and enantioselective fluorescent identification of specific amino acid enantiomers.

The enantiomers of chiral amino acids play versatile roles in biological systems including humans. They are also very useful in the asymmetric synthesis of diverse chiral organic compounds. Therefore, identifying a specific amino acid and distinguishing it from its enantiomer are of great importance. Although significant progress has been made in the development of fluorescent probes for amino acids, most of them are not capable of conducting simultaneous chemoselective and enantioselective detection of a specific amino acid enantiomer. In this article, several fluorescent probes have been designed and synthesized for chemoselective as well as enantioselective recognition of certain amino acid enantiomers. (S)-1 shows greatly enhanced fluorescence in the presence of L-glutamic acid and L-aspartic acid, but produces no or little fluorescence response toward their opposite enantiomers and other amino acids. (R)-4 in combination with Zn2+ shows greatly enhanced fluorescence in the presence of L-serine. (S)-6 is designed for the selective recognition of histidine. Micelles made of an amphiphilic diblock copolymer are used to encapsulate the water-insoluble compound (S)-8 which shows chemoselective as well as enantioselective fluorescence enhancement with L-lysine in the presence of Zn2+ in aqueous solution. The same micelles are also used to encapsulate several (S)-1,1'-binaphthyl-based monoaldehydes (S)-10 for the chemoselective and enantioselective fluorescence recognition of L-tryptophan in the presence of Zn2+ in aqueous solution. These findings have demonstrated that highly selective fluorescence identification of a specific amino acid enantiomer can be achieved by incorporating certain functional groups at the designated locations of the 1,1'-binaphthyls. The binaphthyl core structure of these probes provides both a chirality source and highly tunable fluorescence properties. Matching the structure and chirality of these probes with those of the specific amino acid enantiomers can generate structurally rigid reaction products and give rise to greatly enhanced fluorescence. The strategies of this work can be further expanded to develop fluorescent probes for the specific identification of many amino acids of interest. This should facilitate the analysis of chiral amino acids in various applications. The outlook of this research and its comparison with other methods are also discussed.

Rhombic dodecahedral gold nanoparticles: chiral sensing probes for naked-eye recognition of histidine enantiomers.

Rhombic dodecahedral gold nanoparticles (GNPs) are found to have inherent chirality and can be used as colorimetric probes for naked-eye recognition of histidine enantiomers. Our findings are helpful for developing new GNP-based chiral sensing systems through tuning of nanoparticle morphology.

Highly enantioselective recognition of S-ibuprofen by a host-guest induced chiral nanochannel.

Chirality is an important property, especially for chiral drug enantiomers with huge differences in pharmacology and toxicity. Chiral recognition of drug enantiomers is the first step to understanding the physiological phenomenon and ensuring medical safety. To efficiently identify and isolate these chiral drugs, we prepared a nanochannel. Here, a chiral sensor was fabricated by introducing the host-guest system of pillar[5]arene (WAP5) and phenethylamine into solid-state nanochannels. The chiral guest R-phenethylamine (R-PEA) induced the chirality of the host-guest system and amplified the chiral selectivity for ibuprofen enantiomers in the host-guest-based nanochannels, which was significantly greater than that in the aqueous phase or the R-PEA modified nanochannels. This study provides a strategy to fabricate highly enantioselective nanosensors for chiral drugs.

Importance of molecular symmetry for enantiomeric excess recognition by NMR.

Recently prochiral solvating agents (pro-CSA) came under the spotlight for the detection of enantiopurity by NMR. Chemical shift non-equivalency in achiral hosts introduced by the presence of chiral guests yields observable resonance signal splitting (Δδ) correlating to the enantiomeric excess (e.e.). In this work, symmetry is our lens to explain porphyrin-based supramolecular receptor activity in a chiral environment. Based on extensive NMR analyses of the atropisomeric receptors, the host symmetry is shown to be affected by porphyrin nonplanarity and further desymmetrized in the presence of a chiral guest. As such, the exposed porphyrin inner core (N-H), with its strong hydrogen bond abilities, for the first time, has been exploited in enantiomeric composition analysis. Our approach in e.e. detection by N-H signals appearing in a previously underutilized region of the spectrum (below 0 ppm) shows chemical shift splitting (Δδ) three times more sensitive to enantiomeric compositions than previously reported systems.

A selective electrochemical chiral interface based on a carboxymethyl-β-cyclodextrin/Pd@Au nanoparticles/3D reduced graphene oxide nanocomposite for tyrosine enantiomer recognition.

Palladium@gold nanoparticle modified three-dimensional-reduced graphene oxide (3D-rGO/Pd@Au) was coupled with carboxymethyl-β-cyclodextrin to form a novel nanocomposite (3D-rGO/Pd@Au/CM-β-CD). The 3D-rGO/Pd@Au/CM-β-CD served as a chiral sensing interface for the electrochemical enantiorecognition of tyrosine (Tyr) via a differential pulse voltammetry (DPV) approach. The 3D-rGO/Pd@Au demonstrates good electrical conductivity and efficient catalytic activity as an electrochemical indicator. Simultaneously, the CM-β-CD displays a supramolecular chiral selectivity to reveal a higher binding affinity to the target L-tyrosine (L-Tyr) than to D-tyrosine (D-Tyr). Under the optimized determining conditions, the oxidation peak current ratio of L-Tyr to D-Tyr (IL/ID) was 2.12, meanwhile, the peak currents of the two isomers were linearly proportional to the concentration over the range of 0.8-130 μM with LODs of 52 nM and 96 nM for L- and D-Tyr (S/N = 3), respectively. This approach exhibits distinguished sensitivity, excellent selectivity and good reproducibility, as well as great stability, which can accurately determine the relative content of L- or D-Tyr enantiomers in a racemic solution.

A facile electrochemical chiral sensor for tryptophan enantiomers based on multiwalled carbon nanotube/hydroxypropyl-β-cyclodextrin functionalized carboxymethyl cellulose

The development of facile and convenient sensors for the chiral recognition of enantiomers is of great significance for medical and life science. Herein, a sensitive electrochemical sensor for the chiral recognition of tryptophan (Trp) enantiomers was developed based on the assembly of cellulose grafted with hydroxypropyl-β-cyclodextrins (CMC-CD), multi-walled carbon nanotubes (MWCNTs) and copper ions on the surface of a GCE. The morphologies and electrochemical behaviors of the prepared electrode (GCE/MWCNTs/CMC-CD-Cu) were characterized by differential pulse voltammetry (DPV), FT-IR, XPS, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The oxidation peak current ratio (IL/ID) of DPV could be reached at 2.2 under the optimal experimental conditions. Compared with D-Trp, the higher electrochemical signal of L-Trp was ascribed to the stronger affinity for L-type tryptophan. Additionally, the as-prepared chiral sensor was successfully utilized to analyze the amount of D-Trp in the racemic mixture.

Paper-based fluorescent devices for multifunctional assays: Biomarkers detection, inhibitors screening and chiral recognition

The development of a single analytical platform with different functions is highly desirable but remains a challenge at present. Here, a paper-based device based on fluorescent carbon dots (CDs) functionalized paper/MnO2 nanosheets (MnO2 NS) hybrid devices (PCD/NS) was proposed for single-device multi-function applications. MnO2 NS functioned as a fluorescence quencher of CDs and recognizer of H2O2 released from the oxidase catalyzed system. Fluorescence recovery would occur after the decomposition of MnO2 NS induced by H2O2, by which a simple and effective strategy could be developed for fluorescence monitoring multiplex biological events. Xanthine (XA) sensing, xanthine oxidase (XOD) inhibitors screening analysis and chiral recognition of glucose enantiomers were performed on PCD/NS to investigate the multifunctional application of the paper-based device. By means of PCD/NS, XA could be determined in the range of 0.1–40 µmol/L with a low detection of limit of 0.06 µmol/L. The IC50 value of allopurinol, the model inhibitor of XOD, was sensitively detected to be 7.4 µmol/L. Glucose enantiomers were also recognized in terms of the specific fluorescence response to d-glucose. This work firstly presented a paper-based device capable of biomarkers detection, inhibitors screening and chiral recognition, which enlightened a promising strategy for the construction of multifunctional devices and hold the great potential application in clinical diagnosis and drug discovery.

Chiral induction in carbazole-conjugated covalent organic frameworks: A supersensitive fluorescence sensing platform for chiral recognition

Covalent organic frameworks (COFs) have recently attracted great interest due to their potential applications, including ultrasensitive chiral recognition. We anticipate that optically active chiral COFs could be utilized to recognize chiral molecules more conveniently and intuitively with high enantioselectivity and reactivity. Here, we prepared the chiral functionalized monomer CTp using chiral (+)-diacetyl-L-tartaric anhydride ((+)-Ac-L-Ta) and 1,3,5-triformylphloroglucinol (Tp) to form the chiral (+)-Ac-L-Ta-functionalized Tp. 3,6-diaminocarbazole was then condensed with CTp to obtain carbazole-conjugated chiral COFs (CC-COFs) by CN Schiff base reaction of aldehyde and amino groups in the Tp and carbazole. The prepared optically active chiral COFs show good optical efficiency and thermal stability with the characteristics of porous organic polymers, such as a large specific surface area, adjustable pore structure, and robust skeleton constructed with covalent bonds. CC-COFs exhibit good enantioselectivity and anti-interference ability and can normally recognize the phenylalanine (Phe) enantiomer in the presence of amino acid enantiomers and ions. Furthermore, the fabricated CC-COFs achieve high resolution for optosensing of l- and D-Phe in the linear range of 0.05–5 μmol/L, with detection limits of 0.037 μmol/L and 0.027 μmol/L, respectively. CC-COFs can be applied successfully in the chirality recognition of enantiomers of l- and D-Phe in samples with a recovery of 84.8–99.0%. This strategy of optically active chiral COFs opens up new approaches for enantiomer recognition.

Chiral separation of oxazolidinone analogues by liquid chromatography on polysaccharide stationary phases using polar organic mode

The enantioseparation of four oxazolidinone and one biosimilar thiazolidine derivatives was performed on seven different polysaccharide-type chiral stationary phases (Lux Amylose-1, Lux i-Amylose-1, Lux Amylose-2, Lux Cellulose-1, Lux Cellulose-2, Lux Cellulose-3, Lux Cellulose-4) differing in backbone (cellulose or amylose), substituent or the immobilization technologies (coated or immobilized). Polar organic mode was employed using neat methanol (MeOH), ethanol (EtOH), 2-propanol (IPA) and acetonitrile (ACN) either alone or in combinations as mobile phases. Amylose-based columns with ACN provided the highest enantioselectivities for the studied compounds. The replacement of an oxygen with a sulfur atom in the backbone of the studied analytes significantly alters the enantiomer recognition mechanism. Chiral selector-, mobile-phase-, and interestingly immobilization-dependent enantiomer elution order reversal was also observed. Reversal of elution order and hysteresis of retention and enantioselectivity was further investigated using different mixtures of IPA:MeOH and ACN:MeOH on amylose-type chiral stationary phases. Hysteresis of retention and enantioselectivity was observed on all investigated amylose-type columns and binary eluent mixtures, which can be further utilized for fine-tuning chiral separation performance of the studied columns.

Electrochemical chiral recognition of tryptophan enantiomers based on copper-modified β-cyclodextrin

An electrochemical chiral sensing platform was fabricated by successive modification of Au@Pt bimetallic nanoparticles, poly(cysteine), and Cu 2 -β-CD on the surface of glassy carbon electrode. Good conductivity and high surface area of Au@Pt endowed the sensor with high sensitivity. Cu 2 -β-CD enabled the sensor to effectively identify tryptophan (Trp) enantiomers upon the host–guest interaction with a high the oxidation peak current ratio (I L /I D ) of 2.38. Thus, the simple and efficient sensor can be used for the discrimination of Trp enantiomers. • Cu 2 -β-CD can discriminate Trp enantiomers based on the host–guest interaction. • Au@Pt bimetallic nanoparticles improved the sensitivity of the sensor. • Sensor showed excellent enantioselectivity toward Trp enantiomers. • Facile preparation facilitates the present approach promising. A novel electrochemical chiral sensor was constructed for the discrimination of Tryptophan (Trp) by the modification of Au@Pt bimetallic nanoparticles, poly(cysteine) (PL-Cys), and Cu 2+ -modified β-cyclodextrin (Cu 2 -β-CD) on the surface of glassy carbon electrode. The constructed sensor was characterized by transmission electron microscopy, infrared spectroscopy, UV–vis adsorption spectra, and the electrochemical experiments. The modified Au@Pt endowed the sensor with high surface area and good conductivity. The electropolymerized PL-Cys facilitated the loading of Cu 2 -β-CD based on the electrostatic interaction. As a chiral selector, Cu 2 -β-CD enabled the sensor to effectively identify the Trp enantiomers based on the host–guest interaction with a high the oxidation peak current ratio (I L /I D, I L and I D were the oxidation peak currents of l -Trp and d -Trp measured on the sensor, respectively) of 2.38. Under the optimized conditions, I L /I D increased with the increase of l -Trp in the raceme solution, which was further employed for the detection of Trp in serum samples with satisfactory results. With the good selectivity, stability, and reproducibility, the present electrochemical sensor can be used for the simple, rapid, and efficient chiral recognition and real samples determination.

Voltammetric sensor system based on Cu(II) and Zn(II) amino acid complexes for recognition and determination of atenolol enantiomers

• A chiral sensors based on GCE modified by composites with amino acid complexes of Cu(II) and Zn(II) was developed. • R- and S-Atn interact with the Cu(II) and Zn(II) amino acid complexes by the ligands exchange. • Differences in the maximum currents and the potentials of R-, S-Atn oxidation peaks were observed. • For reliable recognition of R- and S-Atn, the proposed sensors were combined to sensor system by chemometric methods. • The sensor system correctly recognize R- and S-Atn in enantiomeric mixture. For recognition and determination of atenolol (Atn) enantiomers the enantioselective voltammetric sensor system based on glassy carbon electrodes modified by composites of polyarylenephthalide and chiral amino acid complexes of Cu(II) and Zn(II) – glycine- l -alaninate and glycine- l -argininate Cu(II), bis - l -phenylalaninate Zn(II) is developed. The enantioselectivity of the sensors is explained by the presence of chiral amino acids in the complexes which can be exchanged with Atn enantiomers and form mixed-ligand complexes of different stability. The electrochemical and analytical characteristics of the sensors were studied. It was shown that the sensors are cross-sensitive to Atn enantiomers. A sensor system based on them with chemometric processing of analytical signals using the methods of principal components and projection to latent structures was used to recognize and determine S- and R-Atn in mixtures with different ratios of enantiomers. The content of S-Atn was established with a relative standard deviation of less than 9% and recoveries ranging from 95% to 102%. The use of a sensor system makes it possible to eliminate errors of the first kind and to minimize errors of the second kind, to increase the percentage of correctly recognized samples up to 99%.

A renewable electrochemical sensor based on a self-assembled framework of chiral molecules for efficient identification of tryptophan isomers

Molecular self-assembly provides a reasonably effective strategy for the design and construction of chiral sensors. Here, Cu2+ was connected to β-cyclodextrin (β-CD) through coordination to synthesize Cu2-β-CD, subsequently assembled with ammoniated chitosan-MWCNTs (NH2-CS-MWCNTs) by the effect of coordination driver to form a chiral sensing interface Cu2-β-CD/NH2-CS-MWCNTs. Using the electrochemical method, the valid recognition of tryptophan (Trp) isomers was achieved on the self-assembly interface. Under the optimal experimental conditions, the developed sensor exhibited good linearity and satisfactorily renewable ability. Cu2-β-CD/NH2-CS-MWCNTs/GCE showed the capacity to predict the ratio of D-Trp and L-Trp in racemic mixtures and the possibility of qualitative and quantitative determination for Trp isomers. Finally, the electrochemical sensor was used to detect the Trp enantiomers in rat serum, further verifying the feasibility of the sensor in the determination of actual samples. Therefore, the electrochemical chiral sensor not only is used for the recognition of Trp enantiomers but shows great potential in practical applications.

Inducing enantioselective crystallization with and self-assembly of star-shaped hybrid polymers prepared via "grafting to" strategy.

Helical polymers present some interesting and distinctive properties, and one of the most distinguished applications of them is the chiral recognition and resolution of enantiomers. In this work, star-shaped hybrid helical poly (phenyl isocyanide) (PPI) with polyhedral oligomeric silsesquioxanes (POSS) as the core was designed and synthesized by "grafting to" strategy. The homoarm star-shaped hybrid POSS-(PPI)8 was first obtained by the click reaction between azide-modified POSS (POSS-(N3 )8 ) and alkynyl-modified PPI (PPI-Alkynyl). The hybrid POSS-(PPI)8 was with predominated left-handed helical conformation and exhibited excellent ability in the enantioselective crystallization of racemic compounds. In the meantime, heteroarm star-shaped hybrid (PEG)4 -POSS-(PPI)4 was prepared by the click reaction of POSS-(N3 )8 with PPI-Alkynyl and alkynyl-modified poly (ethylene glycol) (PEG-Alkynyl). The hybrid (PEG)4 -POSS-(PPI)4 was amphiphilic, and it could self-assemble to form spherical micelles in aqueous solutions.

A Sensor for the Recognition and Determination of Tryptophan Enantiomers Based on Carbon-Paste Electrode Modified by Enantiomorphic Crystals of Bromotriphenylmethane

A Sensor for the Recognition and Determination of Tryptophan Enantiomers Based on Carbon-Paste Electrode Modified by Enantiomorphic Crystals of Bromotriphenylmethane

L-histidine-regulated zeolitic imidazolate framework modified electrochemical interface for enantioselective determination of L-glutamate

Metal-organic framework (MOF)-based electrochemical interface presents a broad platform for the chiral recognition of amino acids, but the inferior conductivity of most MOFs limits the sensitivity in practical applications of electrochemical sensing. Therefore, the L-histidine-regulated zeolitic imidazolate framework (L-His-ZIF) was proposed as a novel electrochemical interface for simple, efficient, and enantioselective determination of L-glutamate (L-Glu) based on the electrochemical impedance spectroscopy (EIS). Based on the resistance change, the L-His-ZIF interface can be directly used for chiral recognition without the assistance of high-conductive substances, where multiple immobilizations are generally required in MOF-involved voltammetry. The stacked L-His-ZIF nano-polyhedrons provided numerous cavities and high specific surface area, thereby forming adequate chiral recognition sites. Based on the L-His-ZIF interface, the enantioselective detection of l-Glu-was successfully achieved with a good linear relationship with the impedance difference in the range from 0.1 nM to 50 nM with the detection limit of 0.06 nM. This prepared ZIF-functionalized electrode provided the desired enantioselectivity and reproducibility with robust chiral recognition in the real application. More importantly, MOF-modified EIS can be applied for more chiral recognition of enantiomers by various MOF interfaces, which has great potential for applications in pharmaceutical monitoring and biochemical analysis.

Investigation of [MSalen/salophen] (M = Cr3+, Fe3+ or Co3+) capped dinuclear complexes of two novel tetraoxocalix[2](m-hydroxymethyl)arene[2]triazine compounds

In this work, (3,5-bis((4,6-dichloro-1,3,5-triazine-2-yl)oxy)phenyl)methanol was obtained by reacting cyanuric chloride with 3,5-dihydroxybenzyl alcohol at 0 °C. Then, s-triazine bridged calixarene codded as L1 was obtained by reacting the compounds with 3,5-dihydroxybenzyl alcohol. Targed ligands, which we code as L2 and L3, were obtained from the reaction of the L1 coded compound with 4-aminobenzoic acid or 4-hydroxybenzoic acid, respectively. [MSalen/Saloph] capped s-triazine bridged calixarene complexes were obtained from the reaction of the L2 or L3 codded ligand and the [(MSalen/Saloph)2O] (M = Cr3+, Fe3+, Co3+) starting complexes in 1,4-dioxane media. The ligands and complexes were characterized by using 1H-NMR, FT-IR spectroscopy, UV-Vis spectroscopies, magnetic susceptibility, TGA-DTA and elemental analysis techniques. Metal contents of the complexes were determined by using ICP-AES spectroscopy. Calixarenes can be used in many areas such as chiral phase transfer catalyst, recognition of enantiomers, stationary phase in chromatography, recovery of heavy and precious metals molecules or ions from environmental wastes.

L-cysteine capped silver nanoparticles as chiral recognition sensor for ketoprofen enantiomers.

A simple, inexpensive but effective approach for visual chiral recognition of ketoprofen enantiomers was developed using L-cysteine capped silver nanoparticles (L-Cys-AgNPs) as a colorimetric sensor. Upon the addition of R-ketoprofen to L-Cys-AgNPs, rapid aggregation occurred, and the solution changed color from yellow to green. However, the presence of S-ketoprofen did not induce any color change. The results were characterized using UV-Vis, FESEM, FT-IR, SERS, and zeta potential measurements. The chiral assay described in this work is easily distinguished with the naked eyes or using a UV-Vis spectrometer. The sensor revealed a good linear response to ketoprofen enantiomers in the concentration range of 8.33-33.3μM with a detection limit of 4.52 μM and relative standard deviation of 3.73%. The proposed method was utilized for the determination of ketoprofen racemic mixtures in water samples and commercial tablets. The method excels by its simplicity, low cost, and good availability of materials.

Chiral carbon quantum dots as fluorescent probe for rapid chiral recognition of isoleucine enantiomers

Chiral recognition is always a significant and challenging work in analytical chemistry. A fluorescent chiral recognition method based on chiral carbon quantum dots (CCQDs) towards isoleucine (Ile) enantiomers was developed in this work. CCQDs were synthesized by one-step hydrothermal method using l-cysteine as chiral source. The fluorescence intensity of CCQDs enhanced obviously in the presence of L-Ile, but had no observable change in the presence of D-Ile. The response speed of this chiral sensing system is fast, Ile enantiomers can be discriminated by CCQDs within 5 min, the enantioselectivity (IL/ID) can reach up to 2.2. Good linearity for detecting L-Ile was obtained over the concentration range from 0 to 30 mM with a LOD of 0.29 mM. The fluorescence intensity also increased linearly with the enantiomeric percentages of L-Ile in the mixture of Ile enantiomers. Thus, the developed method not only can achieve quantitative detection of L-Ile but also can determine the enantiomeric percentage in racemates. The chiral recognition mechanism can be explained by the difference in binding energy and interaction types between D-Ile and L-Ile with CCQDs by molecular modeling. The current method was applied in detecting L-Ile in real samples of functional drinks, the detection results were in consistent with the results obtained from high performance liquid chromatography, and the recoveries of standard addition were also satisfactory, which verified the reliability of the developed method.

Hybrid supraparticles of carbon dots/porphyrin for multifunctional tongue-mimic sensors

Supraparticles (SPs), such as assembly of inorganic components with organic, have made tremendous attention in biochemical analysis, which represents a novel but challenging research orientation. Herein, a single-SPs multifunctional fluorescent sensor array has been developed for high-throughput detection of heavy metal ions in biofluids, which is based on an inorganic/organic hybrid SPs consisting of carbon dots (CDs) and an easily available porphyrin [5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP)]. TCPP can aggregate with the CDs to form the assembly (CDs/TCPP SPs) through the electrostatic and π-π stacking interaction. There are two independent and clearly separated fluorescence emission peaks at 470 and 668 nm in the resultant CDs/TCPP SPs under 380 nm excitation. As a proof-of concept design, F470, F668, F668/F470 of SPs are chosen as three sensor components to constitute our sensor array. With the addition of metal ions, three sensor components can generate different fluorescence response patterns for discriminating 11 heavy metal ions via principal component analysis (PCA). Additionally, thiols can readily capture Cu2+ to switch the fluorescence of CDs/TCPP initially altered by Cu2+. Hence, CDs/TCPP-Cu2+ ensemble is further demonstrated to be a powerful sensor array for pattern recognition of 7 thiols and even chiral recognition of cysteine enantiomers. This novel strategy avoids the tanglesome synthesis of multiple sensing probes and dedicates an innovative method for the facile establishment of tongue-mimic sensors, which would prospectively sprout more homologous assumptions to broaden its application toward more biosensing fields.

Engineering Homochiral MOFs in TiO2 Nanotubes as Enantioselective Photoelectrochemical Electrode for Chiral Recognition.

Enantioselective sensing of chiral molecules is an important issue for both biomedical research and the pharmaceutical industry. Here, an enantioselective photoelectrochemical (PEC) sensor was constructed by integrating TiO2 nanotubes (NTs) with metal-organic frameworks (MOFs) for the identification of enantiomers. TiO2 NTs prepared by electrochemical anodization can not only be used as the PEC platform but also as the metal-ion precursor to react with terephthalic acid (BDC) to form MIL-125(Ti) in situ. A postsynthetic exchange (PSE) method was used for exchanging the ligand of MIL-125 by 2-aminoterephthalic acid (BDC-NH2) for further functionalization. Homochirality was then successfully introduced into achiral MIL-125-NH2 by postsynthetic modification (PSM) with l-histidine (l-His). The resulting homochiral metal-organic frameworks (MOF)-in-NT architecture exhibits excellent discrimination ability for the chiral recognition of 3,4-dihydroxyphenylalanine (l/d-DOPA) enantiomers. Moreover, by adjusting the charge-carrier separation-induced photocurrent variation mechanism, the as-proposed homochiral PEC electrode exhibits a broad application potential for the discrimination of enantiomers. Because of the construction of binder-free monochiral MOF-in-NT structure directly on a Ti-metal substrate, the valuable feature is that the PEC sensing platform can be used directly, thereby providing a stable, simplified, and low-cost sensing device for the recognition of chiral enantiomers.