A universal strategy for visual chiral recognition of α-amino acids with l-tartaric acid-capped gold nanoparticles as colorimetric probes

Abstract

The ability to recognize and quantify the chirality of alpha-amino acids constitutes the basis of many critical areas for specific targeting in drug development and metabolite probing. It is still challenging to conveniently distinguish the enantiomer of amino acids largely due to the lack of a universal and simple strategy. In this work, we report a strategy for the visual recognition of α-amino acids. It is based on the chirality of L-tartaric acid-capped gold nanoparticles (L-TA-capped AuNPs, ca. 13 nm in diameter). All of 19 right-handed α-amino acids can induce a red-to-blue color change of L-TA-capped AuNP solution, whereas all of the left-handed amino acids (except cysteine) cannot. The chiral recognition can be achieved by the naked eye and a simple spectrophotometer. This method does not require complicated chiral modification, and excels through its low-cost, good availability of materials and its simplicity. Another notable feature of this method is its high generality, and this method can discriminate almost all native α-amino acid enantiomers. This versatile method could be potentially used for high-throughput chiral recognition of amino acids.

Enantiomeric Recognition and Separation by Chiral Nanoparticles

“…NP-based enantiomeric recognition and separation have been widely discussed and studied in the past decade. Studies reported chiral -modified nanomaterials for catalysis [70,71], chiral drug separation [71] and sensing [54,55,56,57,58,59,60,63,68,72,73,74]. In this section, we will focus on the enantiomeric recognition and the fabrication of most commonly used gold and silver materials for chiral NPs.…”

“…At present, this generally involves surface modification using chiral ligands; however, recent advances are making the recognition and separation of enantiomers far simpler. One particular achievement in enantiomeric recognition is colorimetric detection, which uses surface-modified NPs to convert recognition events into color changes observable to the naked eye or a UV-Vis spectrometer [52,53,54,55,56,57,58,59,60,61,62]. This makes it ideal for on-site chiral analysis and provides results instantaneously.…”

Smartphone‐based colorimetric chiral recognition of ibuprofen using aptamers‐capped gold nanoparticles

“…An enantiosensor that can achieve visual discrimination of enantiomers is highly desirable, in which a molecular recognition event is translated into an appreciable color change . Recently, owing to low cost, high sensitivity and simplicity, the metal nanoparticles based colorimetric sensors have been applied to detect carbohydrates , amino acid and proteins in aqueous samples, because targeted analyte can readily induce dispersion/aggregation states of metal nanoparticles and thus the reversible color changes .…”

Chiral recognition and determination of enantiomeric excess of chiral compounds by UV-visible-shortwave near infrared diffuse reflectance spectroscopy with chemometrics

“…The increased development of single-enantiomer pharmaceuticals has enhanced the need for rapid and convenient methods for chiral recognition and determination of enantiomeric excess of chiral compounds. 1 There have been various methods for chiral analysis, such as circular dichroism (CD), 2-4 polarimetry, 5 NMR, 1,6 high performance liquid chromatography (HPLC), [7][8][9] gas chromatography (GC), 10 capillary electrophoresis (CE), [11][12][13][14] mass spectroscopy, 15 uorescence spectrometry, [16][17][18] ultraviolet absorption spectroscopy, [19][20][21][22] UV-visible absorption spectroscopy, [23][24][25] near-infrared spectroscopy, 26 resonance Rayleigh scattering spectroscopy, 27 optically active Raman spectroscopy, 28,29 vibrational circular dichroism spectroscopy, 30,31 ITC, 32,33 colorimetric probes [34][35][36] and so on. Most of them are effective and powerful either in chiral recognition or in determination of enantiomeric excess.…”

“…The above methods have some drawbacks such as needing addition of chiral auxiliary for derivatization, [7][8][9][10][15][16][17][18][19][20][21][22][23][24][25][26] requiring tedious sample pretreatment, [34][35][36] using expensive and sophisticated instruments, [2][3][4][6][7][8][9]28,29,32,33 being time-consuming, 6,30,31 less sensitive, [2][3][4] destructive, 15 only for chiral recognition. 32,33 Additionally, they are all wet analysis and can't be used for all types of chiral compounds.…”