Amino Acid Helical Array Film and Preparation Method Thereof

Abstract

The present disclosure discloses an amino acid helical array film and a preparation method thereof. The amino acid helical array film comprises a substrate and an amino acid helical array uniformly deposited on the substrate. Each amino acid helix is obtained by self-assembling an amino acid with a modifying group. The amino acid is selected from one or more of twenty common natural amino acids or adjacent isomers thereof. The modifying group comprises an N-terminal protecting group and a C-terminal protecting group, wherein the N-terminal protecting group is selected from one or more of carbobenzoxy, a lipid group, t-butoxycarbonyl, and 9-fluorenylmethoxycarbonyl, and the C-terminal protecting group is selected from one or more of nitrophenyl ester, a lipoxy group, and an acylamino group.

Claims

1. An amino acid helical array film, comprising a substrate and an amino acid helical array uniformly deposited on the substrate; wherein each amino acid helix is obtained by self-assembling an amino acid with a modifying group; the amino acid is selected from glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, histidine, or one or more of adjacent isomers of the above amino acids; and the modifying group comprises an N-terminal protecting group and a C-terminal protecting group, wherein the N-terminal protecting group is selected from one or more of carbobenzoxy, a lipid group, t-butoxycarbonyl, and 9-fluorenylmethoxycarbonyl, and the C-terminal protecting group is selected from one or more of nitrophenyl ester, a lipoxy group, and an acylamino group.

2. The amino acid helical array film according to claim 1, wherein the amino acid helical array has a uniform rotation direction in a clockwise or an anticlockwise manner; and the amino acid helix has a diameter range of 300-650 μm.

3. The amino acid helical array film according to claim 1, wherein a material of the substrate is selected from conductive or insulating, transparent or opaque, thermally conductive, organic or inorganic, flexible or rigid metal, glass or polymer.

4. The amino acid helical array film according to claim 1, wherein the amino acid is selected from L-phenylalanine or D-phenylalanine, the N-terminal protecting group is selected from t-butoxycarbonyl, and the C-terminal protecting group is selected from nitrophenyl ester.

5. A preparation method of the amino acid helical array film according to claim 1, wherein a physical vapor deposition is used and specifically comprises: placing an amino acid raw material with a modifying group in an evaporation boat of a reaction chamber and obtaining a self-assembled amino acid helical array film by deposition on a surface of the substrate through a vacuum evaporation coating method.

6. The preparation method of the amino acid helical array film according to claim 5, wherein a distance between the evaporation boat and the substrate is 1-5 cm.

7. The preparation method of the amino acid helical array film according to claim 5, wherein the vacuum evaporation coating method is as follows: vacuumizing the reaction chamber until a vacuum degree is less than or equal to 5×10.sup.−6 mbar, firstly performing heating to a sublimation temperature of the amino acid raw material with a modifying group, then performing heating to a highest temperature, and preserving the temperature for a period of time; the highest temperature is 200-220° C.; and total time from the heating to the sublimation temperature to the end of the highest temperature preserving is recorded as deposition time, selected from 15-60 min.

8. The preparation method of the amino acid helical array film according to claim 7, wherein the deposition time is selected from 30-60 min.

9. The preparation method of the amino acid helical array film according to claim 5, the amino acid raw material with a modifying group is selected from t-butyloxycarboryl-L-phenylalanine-nitrophenyl ester or t-butyloxycarboryl-D-phenylalanine-nitrophenyl ester.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 shows SEM images of the amino acid helical array prepared in example 1 at different magnification times;

[0040] FIG. 2 is a statistical distribution diagram of diameters of the amino acid helical array prepared in example 1;

[0041] FIG. 3 is a confocal microscopy morphological image of the amino acid helical array prepared in example 1;

[0042] FIG. 4 is a fluorescent microscopic image of the amino acid helical array prepared in example 1;

[0043] FIG. 5 is an SEM image of the amino acid helical array prepared in example 15;

[0044] FIG. 6 is an SEM image of the amino acid helical array prepared in example 17;

[0045] FIG. 7 is an SEM image of a film of L-phenylalanine prepared in comparative example 1 deposited on a glass substrate;

[0046] FIG. 8 is an SEM image of an amino acid film deposited on a glass substrate in comparative example 3 by a solvent evaporation method;

[0047] FIG. 9 shows SEM images of the amino acid helical array prepared in example 21 at different magnification times;

[0048] FIG. 10 is a statistical distribution diagram of diameters of the amino acid helical array prepared in example 21;

[0049] FIG. 11 is a confocal microscopy morphological image of the amino acid helical array prepared in example 21; and

[0050] FIG. 12 is an SEM image of the amino acid self-assembled array film prepared in comparative example 4.

DETAILED DESCRIPTION OF THE INVENTION

[0051] The present disclosure is described in further detail below with reference to examples and comparative examples, but embodiments of the present disclosure are not limited thereto.

Example 1

[0052] Firstly 5 mg of t-butoxycarbonyl-(L-)phenylalanine-nitrophenyl ester powder (Boc-(L)F-ONp) (Chem-imprex Int'l. Inc.) was weighed; the weighed t-butoxycarbonyl-(L-)phenylalanine-nitrophenyl ester powder was placed into an evaporation boat in a main generation chamber; a distance between a glass substrate (2 cm×2 cm) and an evaporation boat was adjusted and set to be 1.5 cm; a door of the main generation chamber was closed to form a closed environment after the completion; an air extracting pump was turned on to pre-evacuate the main generation chamber to 0.1 mbar, after an air tightness of the main generation chamber was checked, the main generation chamber was vacuumized to about 1×10.sup.−5 mbar using the air extracting pump, and then a molecular pump was turned on to further vacuumize the main generation chamber until a vacuum degree is less than or equal to 5×10.sup.−6 mbar; and after the vacuum degree reaches the requirement, a temperature control procedure and a deposition time control procedure were set on a temperature control panel of a main console. In the present example, four stages of heating were performed: a first-stage heating: 10 min was set for a room temperature rising to 60° C.; a second-stage heating: 10 min was set for a temperature of 60° C. rising to 160° C.; a third-stage heating: 20 min was set for a temperature of 160° C. rising to 220° C.; and a fourth-stage heating: a temperature was maintained at 220° C.°C. for 15 min; after the deposition is completed, a baffle plate was driven to stop the deposition; a circulating water cooling device was turned on to cool the evaporation boat and the main generation chamber; and after cooling to a room temperature, an amino acid self-assembled helical array film was obtained on a glass substrate.

[0053] FIG. 1 showed SEM images of the amino acid self-assembled helical array prepared in the example at different magnification times. It can be seen by observing (a) that the prepared amino acid helical array was uniformly distributed on the substrate and had a consistent rotation direction in a clockwise manner. It can be seen by observing (b, c) that the helical array was arranged and assembled by a plurality of amino acid needle-shaped crystal fibers.

[0054] FIG. 2 was a statistical distribution diagram of diameters of the amino acid self-assembled helical array prepared in the example. The statistical result showed that the amino acid helical array had a statistical average diameter of 550+/−36 μm, a narrow diameter distribution, and a relatively uniform diameter.

[0055] FIG. 3 was a confocal microscopy image of the amino acid helical array prepared in the example. It can be seen by combining FIG. 1 and the figure that self-assembled crystal fibers at a center of the helical array were tightly clustered and then spread out in an arrangement along a clockwise helix rotation direction.

[0056] FIG. 4 was a fluorescent microscopic image of the amino acid helical array prepared in the example. Under a fluorescence microscope, the amino acid helical array may be observed to have an optical waveguide effect, and fluorescence may be transmitted to an outer layer through crystal fibers in the array, such that the helixes had higher brightness at edges and were relatively dark in the middle.

Examples 2-14

[0057] The preparation process was basically the same as that in example 1. A difference was only that the substrate was replaced by a silicon wafer, a silicon dioxide sheet, a mica sheet (inorganic insulating substrate), a copper sheet, an aluminum sheet, a gold film (electrically conductive and thermally conductive metal substrate), an ITO thermally conductive glass sheet (inorganic electrically conductive substrate), a graphite sheet (hydrophobic electrically conductive substrate), an aluminum foil, a gold foil, silver-plated Polyvinylidene fluoride (flexible electrically conductive substrate) and PlantDesignManagementsystem, and Polyvinyl alcohol (flexible insulating substrate).

[0058] The morphology of the amino acid helical array prepared in each of the above examples was substantially similar to that in example 1, which indicated that the preparation process of the amino acid helical array disclosed in the present disclosure had universality for the substrates of various materials and properties.

Example 15

[0059] The preparation process was basically the same as that in example 1. A difference only lied in that deposition time was different and shortened to 15 min. Specifically, a first-stage heating: 10 min was set for a room temperature rising to 60° C.; a second-stage heating: 10 min was set for a temperature of 60° C. rising to 160° C.; a third-stage heating: 10 min was set for a temperature of 160° C. rising to 220° C.; and a fourth-stage heating: a temperature was maintained at 220° C. for 5 min.

[0060] FIG. 5 was an SEM image of the amino acid helical array prepared in the example. It can be seen from the figure that a rotation direction of the amino acid helical array prepared by the example was consistent with that in example 1 in a clockwise manner. But the helical array had a relatively low assembling density.

Example 16

[0061] The preparation process was basically the same as that in example 1. A difference only lied in that deposition time was different and adjusted to 60 min. Specifically, a first-stage heating: 10 min was set for a room temperature rising to 60° C.; a second-stage heating: 10 min was set for a temperature of 60° C. rising to 160° C.; a third-stage heating: 30 min was set for a temperature of 160° C. rising to 220° C.; and a fourth-stage heating: a temperature was maintained at 220° C. for 30 min.

[0062] Through SEM characterization, a morphology of the amino acid helical array prepared in the example was basically similar to that in example 1. The rotation direction was also consistent in a clockwise manner.

Example 17

[0063] The preparation process was basically the same as that in example 1. A difference only lied in that deposition time was different and extended to 120 min. Specifically, a first-stage heating: 10 min was set for a room temperature rising to 60° C.; a second-stage heating: 10 min was set for a temperature of 60° C. rising to 160° C.; a third-stage heating: 60 min was set for a temperature of 160° C. rising to 220° C.; and a fourth-stage heating: a temperature was maintained at 220° C. for 60 min.

[0064] FIG. 6 was an SEM image of the amino acid helical array prepared in the example. It can be seen from the figure, the amino acid helical array prepared by the example had a relatively high density and no obvious helical structure.

[0065] It can be seen from the SEM images of the amino acid helical arrays prepared in comparative example 1 and examples 15-17, morphologies of the amino acid helical arrays may be adjusted by regulating and controlling the deposition time.

Example 18

[0066] The preparation process was substantially the same as that in example 1. A difference only lied in that mass of the added t-butoxycarbonyl-(L-)phenylalanine-nitrophenyl ester powder varied. Specifically, the mass of the raw material was reduced to 0.5 mg.

[0067] Through SEM characterization, the amino acid helical array prepared in the example had a morphology substantially similar to that prepared in example 15.

Example 19

[0068] The preparation process was substantially the same as that in example 1. A difference only lied in that mass of the added t-butoxycarbonyl-(L-)phenylalanine-nitrophenyl ester powder was adjusted to 10 mg.

[0069] Through SEM characterization, the amino acid helical array prepared in the example had a morphology substantially similar to that prepared in example 1.

Example 20

[0070] The preparation process was substantially the same as that in example 1. A difference only lied in that mass of the added t-butoxycarbonyl-(L-)phenylalanine-nitrophenyl ester powder was increased to 50 mg.

[0071] Through SEM characterization, the amino acid helical array prepared in the example had a morphology substantially similar to that prepared in example 17.

[0072] It can be seen from the SEM images of the amino acid helical arrays prepared in comparative example 1 and examples 18-20, a morphology of the amino acid helical array may also be adjusted by regulating and controlling the mass of the raw material.

Comparative Example 1

[0073] The preparation process was basically the same as that in example 1. A difference only lied in that L-phenylalanine of the same mass was used as a raw material.

[0074] FIG. 7 was an SEM image of L-phenylalanine deposited on a glass substrate. It can be seen from the SEM image, a film of a closely arranged plate-like crystal array prepared in the comparative example did not have a helical structure, which indicated that the amino acid helical array disclosed in the present disclosure must be prepared from terminal group-protected amino acids.

Comparative Example 2

[0075] The preparation process was substantially the same as that in example 1. A difference only lied in that a device used in the comparative example was a conventional physical vapor deposition device with a model of ZFS-500. In the device, a distance between a substrate and an evaporation boat was 40 cm.

[0076] Tests showed that an amino acid helical array film cannot be successfully deposited on a substrate by a same deposition process using the conventional device, indicating that the amino acid helical array disclosed by the present disclosure must be prepared by a relatively small distance between the substrate and the evaporation boat.

Comparative Example 3

[0077] The preparation process was basically the same as that in example 1. A difference only lied in that in the comparative example, an amino acid film was prepared by a solvent evaporation method, specifically: a hexafluoroisopropanol (HFIP) solution of Boc-(L)F-ONp was directly dripped on a glass substrate and an amino acid film was formed after the HFIP was evaporated.

[0078] FIG. 8 was an SEM image of an amino acid film deposited on a glass substrate by a solvent evaporation method. It can be seen from the SEM image, the amino acid film prepared in the comparative example did not have a helical structure, which indicated that the amino acid helical array disclosed in the present disclosure must be prepared from terminal group-protected amino acids by a vacuum evaporation preparation technology.

Example 21

[0079] The preparation process was substantially the same as that in example 1. A difference only lied in that a raw material was replaced with an equal mass of t-butoxycarbonyl-(D-)phenylalanine-nitrophenyl ester powder.

[0080] FIG. 9 was SEM images of the amino acid self-assembled helical array prepared in the example at different magnification times. It can be observed from (a) that an amino acid self-assembly formed a helical array structure. It can be observed from (b) that the helical arrays all rotated in an anticlockwise with the consistent rotation direction which was just opposite to that of the amino acid helical array prepared in example 1. The rotation directions were in a chiral symmetry.

[0081] FIG. 10 was a statistical distribution diagram of diameters of the amino acid self-assembled helical array prepared in the example. The statistical result showed that the amino acid helical array had a statistical average diameter of 550+/−42 μm, a size close to that in example 1, a narrow diameter distribution, and a relatively uniform diameter.

[0082] FIG. 11 was a confocal microscopy image of the amino acid self-assembled helical array prepared in the example. From the figure, it can be seen that crystal fibers at a center of helixes were tightly clustered and then spread out in an arrangement along an anticlockwise helix rotation direction.

[0083] It was indicated that the amino acid helical array disclosed in the present disclosure may adjust the rotation direction of the amino acid by controlling chirality of the amino acid.

Comparative Example 4

[0084] The preparation process was substantially the same as that in example 1. A difference only lied in that a raw material was replaced with a mixture of equal mass of t-butoxycarbonyl-(L-)phenylalanine-nitrophenyl ester powder and t-butoxycarbonyl-(D-)phenylalanine-nitrophenyl ester powder with a total mass of 5 mg.

[0085] FIG. 12 was an SEM image of the amino acid self-assembled array film prepared in the comparative example. From the SEM image, the amino acid self-assembled array prepared in the example was a random, irregular, and non-uniform film, indicating that the amino acid helical array disclosed in the present disclosure must be prepared from a modified amino acid of a single chirality.