A chiral device for amino acid enantiomer identification

Abstract

This invention relates to a chiral device for identifying enantiomers of amino acids, which can be used to distinguish different enantiomeric configurations of the same amino acid. Light is incident from a substrate along the z-direction, passing sequentially through a glass substrate and a gold nanorod composite structure. The gold nanorod composite structure consists of a double L-structure and disjointed tandem nanorods, making full use of gaps and structural asymmetric absorption to achieve a circular dichroism signal of 0.147 in the near-infrared 0.6–1.7 μm band. The refractive index sensitivity at the peak of the circular dichroism spectrum can reach 324 nm / RIU, enabling the identification of amino acid enantiomers.

Description

Technical Field

[0001] This utility model relates to the field of optical materials technology, specifically to a chiral device for identifying amino acid enantiomers. Background Technology

[0002] 1. Chirality describes the geometric property of an object and its mirror image in three-dimensional space, which cannot be perfectly superimposed through rotation or translation. In molecular chemistry, chiral molecules specifically refer to stereoisomers (i.e., enantiomers) that have one or more pairs of non-coincident mirror images of each other.

[0003] 2. Circular dichroism refers to the difference in absorption of left- and right-circularly polarized light by a substance. When circularly polarized light passes through a chiral substance, a difference in absorption between the left and right circularly polarized light will occur. This difference can be characterized by measuring the circular dichroism spectrum.

[0004] 3. The biological activity of many bioactive substances, such as drugs, proteins, and nucleic acids, is often closely related to the chirality of the molecule. Molecules with different chiralities may have different biological activities, toxicities, or pharmacological effects. For example, one chiral isomer of a certain drug may have therapeutic effects, while another chiral isomer may have side effects or even toxicity. Therefore, accurately identifying and distinguishing chiral molecules is of great significance for drug development and clinical treatment. Summary of the Invention

[0005] 1. The sensitivity of circular dichroism (EDC) for amino acid detection can be affected by various factors. On the one hand, the concentration of the amino acid itself may be low, requiring a highly sensitive detection method for accurate detection. On the other hand, the intensity of the EDC signal may be weak, necessitating highly sensitive instruments and techniques for detection. For example, when using EDC to detect amino acids, it may be necessary to use a high-concentration amino acid solution or employ methods to enhance the EDC signal, such as using planar composite metal micro / nano structures.

[0006] 2. Chiral enantiomer identification technology based on plasmon-enhanced circular dichroism (PDC) utilizes planar composite metal micro / nano structures to achieve highly sensitive detection of chiral molecules such as amino acids, which helps improve drug quality and safety. Rapid and accurate detection and identification of chiral molecules is of great significance in the fields of medicine, chemistry, and biology.

[0007] 3. This utility model designs a novel chiral device that can induce the circular dichroism chromatogram of amino acids to the near-infrared band, while also achieving a significant enhancement of the circular dichroism signal. It not only considers the peak size of the circular dichroism chromatogram but also the detection sensitivity, achieving a competitive refractive index sensitivity.

[0008] 4. The optical properties of gold nanorods can be altered by modulating the interactions between them according to plasmon hybridization coupling modes. Specifically, this approach offers several advantages: Firstly, increasing the inter-structural gap on top of the double-L chiral structure significantly enhances the structure's localization ability to light. Secondly, employing a staggered connection method for the gold nanorods further increases chirality in the overall structure, making the difference between left and right circularly polarized light more pronounced. This design not only enhances the circular dichroism signal but also broadens the detection band, providing a novel solution for the high-sensitivity circular dichroism detection of amino acids, greatly improving the accuracy and effectiveness of detection.

[0009] 5. A chiral device for the identification of amino acid enantiomers was designed. A chiral unit structure array was arranged on a glass substrate. The chiral unit structure is a staggered double-rod series double-L-shaped structure. Based on the angularly symmetrical double-L-shaped structure, the staggered double rods are connected with gaps to make full use of the coupling between gold nanorods to enhance circular dichroism and improve the sensitivity of enantiomer identification. The chiral structure is uniformly arranged in both the transverse (x-direction) and longitudinal (y-direction). Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a chiral device structure for amino acid enantiomer identification provided by an example of this utility model;

[0011] Wherein: 1 is a glass substrate; 2 is a gold nanorod composite structure;

[0012] Figure 2 , 3 These are, respectively, a three-dimensional structure and a top view schematic diagram of the series double-L structure unit provided in the embodiments of this utility model.

[0013] Where: w is the width of the gold nanorod; h is the thickness of the gold nanorod; P x P y L1 represents the period of the array unit structure in the x and y directions; L2 represents the length of the misaligned nanorod; L3 represents the length of the double-L structure long rod; and D represents the gap width.

[0014] Figure 4 This is the transmission spectrum and circular dichroism of the optimal structure of this utility model under left and right circularly polarized light;

[0015] Figure 5 This is the circular dichroism spectrum of the optimal structure of this utility model when the refractive index of the environment changes;

[0016] Figure 6 This is the refractive index sensitivity of the optimal structure of this utility model at peak 1 and peak 2 in circular dichroism spectroscopy. Detailed Implementation

[0017] The optimal structural example of this utility model will be described in detail below with reference to the accompanying drawings. It should be noted that the optimal structural example described herein is only for illustration and explanation of this utility model and does not constitute any limitation on this utility model.

[0018] See appendix Figure 1 , 2 This utility model provides a schematic diagram and a three-dimensional view of a chiral device array structure for amino acid enantiomer identification. It is a tandem double-L chiral structure with misaligned nanorods. There are 10 nm gaps between the misaligned nanorods and the L-structure, as well as between the long and short rods of the L-structure. Along the incident light direction, the structure sequentially includes a glass substrate 1 and a gold nanorod composite structure 2. The tandem double-L chiral structure is composed of rectangular units that extend periodically in the horizontal and vertical directions (x and y directions, respectively) within a horizontal plane. The period in the x-direction is 800 nm, and the period in the y-direction is 1000 nm. The gold nanorod composite structure has a uniform thickness of h and a uniform width of w.

[0019] See appendix Figure 3 This is a top view of the series-connected double-L structure unit provided in this utility model embodiment. First, the double-L structures are diagonally distributed at the upper left and lower right of the structure unit, where the length of the longer rod in the double-L structure is defined as L2, and the length of the shorter rod is defined as L3. Then, the double-L structures are connected in series using staggered double nanorods, with a gap connection method, and the length of the staggered nanorods is defined as L... 1， Increase the coupling channels inside the structure; finally, since the charge distribution greatly affects the circular dichroism intensity of the structure, the structure is divided as much as possible here, increasing the gaps and increasing the complexity of the charge distribution, which improves the structure's localization ability to light and enhances the structure's circular dichroism.

[0020] The specific structural parameters of the optimal tandem double L structure provided in this embodiment are as follows: the thickness of the glass substrate and the thickness of the gold nanorods are set to 50 nm and 80 nm respectively; the length of the middle asymmetric double nanorods is 220 nm; the length of the short rod of the L-shaped structure is 210 nm and the length of the long rod is 290 nm; the gap between the rods is fixed at 10 nm.

[0021] See appendix Figure 4 The incident light wavelength range was set to near-infrared 0.6-1.7 μm, incident from below the glass substrate. When used for enantiomer identification, left and right circularly polarized light were used separately. A light receiver was placed above the structure to statistically analyze its transmittance. Subsequently, the circular dichroism formula CD=T was applied. RCP -T LCP Calculations show that, under the optimal structure of this invention, the circular dichroism chromatograph achieves a maximum circular dichroism signal of 0.147 at a wavelength of 980 nm.

[0022] See appendix Figure 5 The optimal structure of this utility model is a circular dichroism chromatogram when the refractive index of the environment changes; the refractive index of the amino acid solution is around 1.4, and the step size of the environmental refractive index from 1.36 to 1.46 is set to 0.02. Figure 5 The circular dichroism chromatogram showed a significant shift at peaks 1 and 2 at wavelengths of approximately 730 nm and 1110 nm.

[0023] See appendix Figure 6 This is the refractive index sensitivity of the optimal structure in this utility model embodiment, based on... Figure 5 The refractive index sensitivity at peak 1 and peak 2 was calculated for circular dichroism spectroscopy when the refractive index of the environment changes. The refractive index sensitivity of peak 1 and peak 2 is 299 nm / RIU and 343 nm / RIU, respectively. The refractive index sensitivity at peak 2 has a certain advantage in the existing structure.

[0024] Formula for calculating refractive index sensitivity: , where n i n j These represent the changes in refractive index between adjacent elements, λ. i , λ j These are the incident wavelengths at the positions of the circular dichroism peaks corresponding to two adjacent refractive indices.

[0025] Finally, it should be noted that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A chiral device for the discrimination of amino acid enantiomers, characterized in that Chiral unit structures are arranged in an array on a glass substrate. The chiral unit structure is a staggered double-bar series double-L-shaped structure. Based on the angularly symmetrical double-L-shaped structure, staggered double bars are connected with gaps to fully utilize the coupling between gold nanorods to enhance circular dichroism and improve the sensitivity of enantiomer identification. The chiral unit structures are uniformly arranged in both the transverse (x-direction) and longitudinal (y-direction).

2. The chiral device for amino acid enantiomer identification according to claim 1, characterized in that... The short rod of the double-L structure is 210 nm long, the long rod is 290 nm long, the rod width is 80 nm, and the rod thickness is 50 nm. The double-L structure is connected in series by misaligned nanorods.

3. The chiral device for amino acid enantiomer identification according to claim 1, characterized in that the misaligned double gold nanorods are misaligned and connected, wherein the misaligned nanorods are 220 nm long and have the same width and thickness as the double L-structured nanorods, and the rods are connected by gaps with a gap width of 10 nm.

4. The chiral device for the enantiomeric discrimination of amino acids according to claim 1, characterized in that The chiral structure array has a period of 800 nm in the x-direction and a period of 1000 nm in the y-direction.

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