Fluorescent molecule-loaded redispersible powder and its use in fingerprint imaging
By using redispersible powder with EVA latex as a carrier, the complexity of existing potential fingerprint detection methods and the problems of NIR-II fluorescent dye aggregation quenching are solved, achieving high-resolution, sensitive, and selective fingerprint development.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HONGSHI (JIANGSU) NEW MATERIAL TECH CO LTD
- Filing Date
- 2023-08-08
- Publication Date
- 2026-05-08
AI Technical Summary
Existing potential fingerprint detection methods are complex, expensive, highly toxic, and have poor stability in real-world environments. Furthermore, NIR-II fluorescent dyes are prone to fluorescence quenching in aggregated states, which limits their application.
EVA latex was used as a carrier for water-soluble NIR-II fluorescent dyes. It was spray-dried to form a redispersible powder. Combined with polyvinyl alcohol and an anti-caking agent, the dispersibility and luminescence effect of the fluorescent dyes were improved. The side chain structure of EVA latex was used to increase the distance between molecular chains and reduce dye aggregation.
It achieves high-resolution, sensitive, and selective latent fingerprint development on different material surfaces, enhances fluorescence luminescence, and the powder has good solubility in ethanol, making it easy to use.
Smart Images
Figure CN117264625B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fingerprint detection technology, specifically to a redispersible powder loaded with fluorescent molecules and its application in fingerprint imaging. Background Technology
[0002] The uniqueness of fingerprints makes them crucial in forensic investigations. Among existing crime scene fingerprints, the elusive nature of latent fingerprints is the most difficult to identify. In recent years, researchers have developed several new methods for latent fingerprint detection, such as chemical fumigation, multi-metal deposition, and fluorescent staining. However, their complex and expensive preparation routes, potential toxicity, destructive testing processes, and poor stability in real-world environments limit their further application. Therefore, developing simple, low-toxicity new strategies for latent fingerprint detection is urgently needed.
[0003] Near-infrared II (NIR-II, 1000-1700 nm) fluorescent dyes, as a class of organic optical materials with great potential for clinical translation, are widely used in biosensing, optical imaging, and other fields due to their good biocompatibility, excellent chemical structural stability, and easily tunable optical properties. However, the inherent hydrophobicity of the conjugated backbone of fluorescent dyes makes them prone to fluorescence quenching in the aggregated state, hindering the further application of NIR-II fluorescent dyes.
[0004] In recent years, researchers have developed some NIR-II fluorescent dyes with good fluorescence brightness in aqueous or solid phases by controlling the structure of fluorescent dyes. However, compared with chemical structural modifications (such as introducing steric groups or side chain modifications) to regulate the aggregated optical properties of fluorescent molecules, using non-covalent interactions to combine specific materials with fluorescent dyes to reduce intermolecular interactions and thus improve the fluorescence brightness of the materials is a simpler and cheaper method.
[0005] Vinyl acetate-ethylene copolymer emulsion (EVA latex) is a polymeric emulsion obtained through free radical polymerization using vinyl acetate and ethylene monomers as basic raw materials. Currently, no applications of EVA latex in improving the development of fluorescent dyes have been found. Summary of the Invention
[0006] The purpose of this invention is to provide a redispersible powder loaded with fluorescent molecules and its application in fingerprint imaging. The redispersible powder of this invention uses EVA as a carrier for water-soluble NIR-II fluorescent dyes. While fully preserving the luminescence characteristics of water-soluble NIR-II fluorescent dyes, it can effectively improve the fluorescence luminescence effect and realize NIR-II fluorescence development of fingerprints on different material surfaces.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A redispersible powder loaded with fluorescent molecules, comprising EVA latex, water-soluble NIR-II fluorescent dye, and polyvinyl alcohol.
[0009] Preferably, the water-soluble NIR-II fluorescent dye comprises 4,9-bis(6-hexyltrimethylammonium bromide)-9H-fluoren-2-yl)thienyl)-6,7-bis(4-hexyloxy)phenyl)-[1,2,5]thiadiazole[3,4-g]quinoxaline (Q-TTQF).
[0010] Preferably, the redispersible powder, on a dry matter basis, comprises an EVA latex, a water-soluble NIR-II fluorescent dye, and polyvinyl alcohol in a mass ratio of 950:4.75-190:10.
[0011] In this invention, "measured by dry matter" means using the dry weight of the substance as the unit of measurement, without considering the solvent contained therein.
[0012] Preferably, the redispersible powder further includes an anti-caking agent.
[0013] The anti-caking agent in this invention includes fumed silica.
[0014] The present invention also provides a method for preparing the above-mentioned redispersible powder, comprising the following steps:
[0015] (1) Dissolve the water-soluble NIR-II fluorescent dye in water to obtain a fluorescent dye solution;
[0016] (2) Dissolve polyvinyl alcohol in water to obtain a polyvinyl alcohol solution;
[0017] (3) Mix the fluorescent dye solution obtained in step (1), the polyvinyl alcohol solution obtained in step (2), and EVA latex, and stir to obtain a mixture;
[0018] (4) Spray dry the mixture obtained in step (3), collect the dried powder, add an anti-caking agent, and obtain the redispersible powder.
[0019] Preferably, the fluorescent dye solution in step (1) has a mass percentage of 10%.
[0020] Preferably, the polyvinyl alcohol solution in step (2) has a mass percentage of 20%.
[0021] Preferably, the anti-caking agent in step (4) is 0.5%-10% of the redispersible powder by mass; more preferably 1%-8%; and most preferably 5%.
[0022] The present invention also provides the application of the above-mentioned redispersible powder in fingerprint imaging.
[0023] The present invention also provides a fingerprint imaging method, comprising the following steps:
[0024] S1. Mix the above redispersible powder with ethanol and dissolve it to obtain a mixed solvent;
[0025] S2. Spray the mixed solvent obtained in step S1 onto the surface of the object to be imaged with fingerprints, and dry it to obtain an object surface containing redispersible powder.
[0026] S3. Use a laser to irradiate the surface of the object containing redispersible powder obtained in step S2 to obtain fingerprint patterns.
[0027] Preferably, the mass ratio of the redispersible powder to ethanol in step S1 is 1:5-15; more preferably 1:5-12; and most preferably 1:9.
[0028] Preferably, the object to be imaged for fingerprints in step S2 is either plastic or glass.
[0029] The beneficial effects of this invention are as follows:
[0030] (1) Because the side chains of EVA copolymer contain abundant acetoxy groups, the distance between polymer molecular chains is greatly increased. The powder formed by drying EVA latex with hot air spray, cold blowing and cyclone separation can effectively disperse water-soluble NIR-II fluorescent dye molecules, reduce the molecular aggregation of water-soluble NIR-II fluorescent dye, and thus improve the fluorescence effect. EVA is selected as the carrier of water-soluble NIR-II fluorescent dye. Its good fluidity avoids the dye powder from being stuck and adhering on the substrate, further improving the effect of fluorescent imaging of dye on the surface of the object.
[0031] (2) The redispersible powder of the present invention uses EVA as a carrier for water-soluble NIR-II fluorescent dye. While fully preserving the luminescence characteristics of water-soluble NIR-II fluorescent dye, it can effectively improve the fluorescence luminescence effect and realize NIR-II fluorescence development of fingerprints on different material surfaces.
[0032] (3) The Q-TTQF in the redispersible powder of the present invention has good NIR-II fluorescence performance, good optical stability and low toxicity. This small molecule can make the latent fingerprint development have high resolution, sensitivity and selectivity. The application of the redispersible powder of the present invention improves the resolution, sensitivity and selectivity of latent fingerprint development. At the same time, the redispersible powder has good solubility in ethanol and is easy to use. Attached Figure Description
[0033] Figure 1The effect of the mass doping ratio of EVA / Q-TTQF in redispersible powder on fluorescence intensity.
[0034] Figure 2 The fingerprint pattern obtained by applying the redispersible powder of Example 6 of the present invention. Detailed Implementation
[0035] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
[0036] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention.
[0037] This invention does not limit the source of the raw materials used. Unless otherwise specified, all raw materials used in this invention are commercially available products commonly used in this technical field. Specifically, 4,9-bis(6-hexyltrimethylammonium bromide)-9H-fluorene-2-yl)thiophene)-6,7-bis(4-hexyloxy)phenyl)-[1,2,5]thiadiazole[3,4-g]quinoxaline (Q-TTQF) was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., product number 103991; the anti-caking agent was R972 fumed silica; the EVA latex had a solid content of 58%, a viscosity of 3150 mPa·s, and a vinyl acetate to ethylene ratio of 90:10; polyvinyl alcohol had a viscosity of 5 mPa·s at a concentration of 4% by mass and a degree of hydrolysis of 80-95% mol.
[0038] Example 1: A redispersible powder and its preparation method
[0039] The redispersible powder, wherein, on a dry matter basis, the mass ratio of the EVA latex, the water-soluble NIR-II fluorescent dye, and the polyvinyl alcohol is 950:4.75:10.
[0040] Specifically, the preparation method is as follows:
[0041] (1) Dissolve 50g of Q-TTQF in 450g of water to obtain a 10% Q-TTQF solution for later use.
[0042] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0043] (3) Mix 47.5g Q-TTQF solution, 50g polyvinyl alcohol solution and 1638g EVA latex, and stir at 300rpm for 30min to obtain a mixture.
[0044] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0045] Example 2: A redispersible powder and its preparation method
[0046] The redispersible powder, wherein, on a dry matter basis, the mass ratio of the EVA latex, the water-soluble NIR-II fluorescent dye, and the polyvinyl alcohol is 950:9.5:10.
[0047] Specifically, the preparation method is as follows:
[0048] (1) Dissolve 50g of Q-TTQF in 450g of water to obtain a 10% Q-TTQF solution for later use.
[0049] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0050] (3) Mix 95g Q-TTQF solution, 50g polyvinyl alcohol solution and 1638g EVA latex, and stir at 300rpm for 30min to obtain a mixture.
[0051] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0052] Example 3: A redispersible powder and its preparation method
[0053] The redispersible powder, wherein, on a dry matter basis, the mass ratio of the EVA latex, the water-soluble NIR-II fluorescent dye, and the polyvinyl alcohol is 950:19:10.
[0054] Specifically, the preparation method is as follows:
[0055] (1) Dissolve 50g of Q-TTQF in 450g of water to obtain a 10% Q-TTQF solution for later use.
[0056] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0057] (3) Mix 190g Q-TTQF solution, 50g polyvinyl alcohol solution and 1638g EVA latex, and stir at 300rpm for 30min to obtain a mixture.
[0058] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0059] Example 4: A redispersible powder and its preparation method
[0060] The redispersible powder, wherein, on a dry matter basis, the mass ratio of the EVA latex, the water-soluble NIR-II fluorescent dye, and the polyvinyl alcohol is 950:95:10.
[0061] Specifically, the preparation method is as follows:
[0062] (1) Dissolve 95g of Q-TTQF in 855g of water to obtain a 10% Q-TTQF solution for later use.
[0063] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0064] (3) Mix 950g Q-TTQF solution, 50g polyvinyl alcohol solution and 1638g EVA latex, and stir at 300rpm for 30min to obtain a mixture.
[0065] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0066] Example 5: A redispersible powder and its preparation method
[0067] The redispersible powder, wherein, on a dry matter basis, the mass ratio of the EVA latex, the water-soluble NIR-II fluorescent dye, and the polyvinyl alcohol is 950:190:10.
[0068] Specifically, the preparation method is as follows:
[0069] (1) Dissolve 190g of Q-TTQF in 1710g of water to obtain a 10% Q-TTQF solution for later use.
[0070] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0071] (3) Mix 1900g Q-TTQF solution, 50g polyvinyl alcohol solution and 1638g EVA latex, and stir at 300rpm for 30min to obtain a mixture.
[0072] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0073] Comparative Example 1: A redispersible powder and its preparation method
[0074] The difference between this embodiment and Embodiment 1 is that no EVA latex is added.
[0075] Specifically, the preparation method is as follows:
[0076] (1) Dissolve 50g of Q-TTQF in 450g of water to obtain a 10% Q-TTQF solution for later use.
[0077] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0078] (3) Mix 50g of Q-TTQF solution and 50g of polyvinyl alcohol solution and stir at 300rpm for 30min to obtain a mixture.
[0079] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0080] Fluorescence intensity detection
[0081] 10g of the obtained redispersible powder was dissolved in 90g of ethanol to obtain a Q-TTQF / EVA mixed solvent, which was then placed in a spray bottle. A layer of the prepared Q-TTQF / EVA mixed solvent was sprayed onto the surface of a plastic object requiring fingerprint imaging. After drying, the object surface was imaged and detected using an imager and an 808nm laser. The NIR-II fluorescence emission intensity of the redispersible powder was normalized, and the results are as follows: Figure 1 As stated above.
[0082] The results are shown in Table 1 and Figure 1 As shown.
[0083] Table 1
[0084]
[0085]
[0086] Table 1 shows the mass doping ratios of EVA and Q-TTQF in each embodiment. According to Table 1 and... Figure 1 It can be seen that the fluorescence emission intensity of the undoped EVA Q-TTQF solid powder in Comparative Example 1 is extremely weak. With increasing EVA concentration, the NIR-II fluorescence emission intensity of the Q-TTQF solid powder shows a significant increase. When the ratio of Q-TTQF mass concentration to doped EVA mass concentration exceeds 1:100, the NIR-II fluorescence emission intensity of the Q-TTQF solid powder does not significantly increase with further addition of EVA.
[0087] The above results indicate that, based on dry matter, the optimal mass doping ratio of EVA to Q-TTQF is 100:1.
[0088] Example 6: A redispersible powder and its preparation method
[0089] The redispersible powder, wherein, on a dry matter basis, the mass ratio of the EVA latex, the water-soluble NIR-II fluorescent dye, and the polyvinyl alcohol is 950:50:10.
[0090] The preparation method is as follows:
[0091] (1) Dissolve 50g of Q-TTQF in 450g of water to obtain a 10% Q-TTQF solution for later use.
[0092] (2) Dissolve 10g of polyvinyl alcohol in 40g of water to obtain a 20% polyvinyl alcohol solution for later use.
[0093] (3) Mix 500g Q-TTQF solution, 50g polyvinyl alcohol solution and 1638g EVA latex, and stir at 300rpm for 30min to obtain a mixture.
[0094] (4) Spray dry the mixture obtained in step (3). The inlet air temperature of the spray dryer is 140°C and the outlet air temperature is 90°C. Collect the dried powder (moisture content 5%-10%) and add 5% anti-caking agent to obtain the redispersible powder.
[0095] Dissolve 10g of the obtained redispersible powder in 90g of ethanol to obtain a Q-TTQF / EVA mixed solvent, and place it in a spray bottle. Spray a layer of the prepared Q-TTQF / EVA mixed solvent onto the surface of the object requiring fingerprint imaging (such as plastic or glass). After drying, use an imager and an 808nm laser to image and detect the surface of the object. The results are as follows. Figure 2 As stated above.
[0096] In summary, the redispersible powder of the present invention uses EVA as a carrier for water-soluble NIR-II fluorescent dyes. While fully preserving the luminescence characteristics of water-soluble NIR-II fluorescent dyes, it can effectively improve the fluorescence luminescence effect and realize NIR-II fluorescence development of fingerprints on different material surfaces.
[0097] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.
Claims
1. A redispersible powder loaded with fluorescent molecules, characterized in that, It includes EVA latex, water-soluble NIR-II fluorescent dyes, and polyvinyl alcohol.
2. The redispersible powder according to claim 1, characterized in that, On a dry matter basis, the mass ratio of the EVA latex, water-soluble NIR-II fluorescent dye, and polyvinyl alcohol is 950:4.75-190:
10.
3. The redispersible powder according to any one of claims 1-2, characterized in that, It also includes an anti-caking agent; the anti-caking agent includes fumed silica.
4. A method for preparing the redispersible powder according to any one of claims 1-3, comprising the following steps: (1) Dissolve the water-soluble NIR-II fluorescent dye in water to obtain a fluorescent dye solution; (2) Dissolve polyvinyl alcohol in water to obtain a polyvinyl alcohol solution; (3) Mix the fluorescent dye solution obtained in step (1), the polyvinyl alcohol solution obtained in step (2), and EVA latex, and stir to obtain a mixture; (4) Spray dry the mixture obtained in step (3), collect the dried powder, add an anti-caking agent, and the redispersible powder is obtained.
5. The preparation method according to claim 4, characterized in that, The anti-caking agent mentioned in step (4) is 0.5%-10% of the mass of the redispersible powder.
6. The application of the redispersible powder according to any one of claims 1-3 or the redispersible powder prepared by the preparation method according to any one of claims 4-5 in fingerprint imaging.
7. A fingerprint imaging method, comprising the following steps: S1. Mix the redispersible powder according to any one of claims 1-3 or the redispersible powder prepared by the preparation method according to any one of claims 4-5 with ethanol and dissolve to obtain a mixed solvent; S2. Spray the mixed solvent obtained in step S1 onto the surface of the object to be imaged, and dry it to obtain an object surface containing redispersible powder. S3. Use a laser to irradiate the surface of the object containing redispersible powder obtained in step S2 to obtain fingerprint patterns.
8. The fingerprint imaging method according to claim 7, characterized in that, The mass ratio of the redispersible powder to ethanol in step S1 is 1:5-15.
9. The fingerprint imaging method according to claim 8, characterized in that, The object to be imaged in step S2 is either plastic or glass.
Citation Information
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