A bifunctional blue developing stain based on protein targeting

Abstract

This invention provides a protein-targeting bifunctional blue developing agent. Commercially available Prussian blue (Tianjin Zhonglian CAS: 14038-43-8) is used, with water as the solvent and benzalkonium chloride as the dispersant, and is ultrasonically dissolved to form a 4% (w / w) Prussian blue aqueous solution. It can be used to develop latent fingerprints or blood fingerprints containing grease on a sample using methods such as drop casting, spraying, and immersion. Under ambient light, the fingerprint turns blue under the action of the developing solution. This invention is applicable to most non-permeable samples and some semi-permeable samples. The dye formulation provided by this invention has low cost, simple preparation, rapid color development, easy operation, and is environmentally friendly. It can broaden new methods for fingerprint development in criminal investigations.

Description

Technical Field

[0001] This invention belongs to the field of material preparation optimization and fingerprint development, specifically relating to a bifunctional blue developing dye for latent fingerprints and blood fingerprints based on protein targeting. Background Technology

[0002] Fingerprints, as crucial physical evidence for identification in forensic science, play a vital role in criminal justice. With the advancement of modern technology, new materials are constantly emerging in the field of fingerprint development. Currently, fingerprint development technology mainly revolves around chemical, physical (instrumental analysis), and biological techniques. For mixed fingerprints encountered in criminal justice, multifunctional fingerprint developing materials or universal developing materials remain a hot topic and a challenge in forensic science research. Compared to traditional blood-developing reagents, such as tetramethylbenzidine (TMB), amino black 10B, and DFO, these reagents have drawbacks such as high toxicity, cumbersome operation, or environmental hazards. Developing a reagent that can develop both blood and latent fingerprints while being environmentally friendly and safe is the current trend.

[0003] Prussian blue has a cubic unit cell structure and was among the first synthetic coordination compounds. Its chemical formula is Fe₄[Fe(CN)₆]. 3· nH₂O is a stable complex structure formed by the assembly of ferric, ferrous, and cyanide ions through strong coordination bonds. This compound is stable at room temperature and pressure, insoluble in water, but soluble in acids and alkalis. Its particle size can be adjusted and controlled according to different preparation methods. Initially, this material was widely used for coloring paints, inks, crayons, and other materials due to its deep blue color and high adsorption properties. In 1978, Prussian blue was first reported to possess excellent electrochemical properties. Its porous structure and internal exchangeable ions have led to extensive research in electrochemistry, optics, magnetism, biomedicine, and many other fields. In the medical field, Prussian blue can not only be used as a drug carrier, but in 2003 it was also approved by the U.S. Food and Drug Administration (FDA) as an antidote for treating radioactive heavy metals containing thallium or cesium. In medical imaging, Prussian blue is used as a contrast agent due to its strong absorption in the near-infrared region, high photothermal conversion rate, and paramagnetism. In the field of catalysis, Prussian blue and its derivatives can degrade organic pollutants or contribute to the production of clean energy, etc. However, there are no reports of using Prussian blue as a small particle suspension for fingerprint imaging. Summary of the Invention

[0004] One of the objectives of this invention is to provide new applications for Prussian blue.

[0005] The new application of Prussian blue provided by this invention is the development of latent fingerprints and blood fingerprints.

[0006] Another object of the present invention is to provide a bifunctional developing dye.

[0007] The bifunctional developing dye provided by this invention comprises the following components: Prussian blue nanoparticles, a cationic surfactant, and water.

[0008] The cationic surfactant may be benzalkonium chloride;

[0009] In the bifunctional developing dye, the mass percentage of Prussian blue nanoparticles can be 0.5-6%, specifically 4%.

[0010] The mass percentage of the cationic surfactant can be 0.1-1%, specifically 0.5%.

[0011] The Prussian blue nanoparticles have a particle size of 40nm-60nm.

[0012] The above-mentioned bifunctional developing dye is prepared by a method including the following steps:

[0013] Water and cationic surfactant are added to Prussian blue nanoparticles and mixed to obtain Prussian blue aqueous solution (Prussian blue nanoparticle suspension), which is a bifunctional developing dye.

[0014] In the above method, the Prussian blue nanoparticles are prepared by a method including the following steps: Prussian blue nanoparticles are obtained by reacting potassium ferrocyanide and ferric chloride by chemical precipitation.

[0015] The Prussian blue nanoparticles have a particle size of 40nm-60nm;

[0016] In the obtained bifunctional developing dye, the mass percentage of Prussian blue nanoparticles can be 0.5%-6%, specifically 2%;

[0017] The mass percentage of the cationic surfactant can be 0.1%-1%, specifically 0.2%;

[0018] The cationic surfactant may be benzalkonium chloride.

[0019] The present invention also provides a method for developing latent fingerprints and / or blood fingerprints.

[0020] The method for developing latent fingerprints and / or blood fingerprints provided by the present invention is as follows: the above-mentioned bifunctional developing dye is applied to the object, left to stand, and under ambient light, the blood fingerprint or latent fingerprint containing oil on the object turns blue under the action of the developing solution, thereby realizing the development of blood fingerprints or latent fingerprints containing oil on the object.

[0021] Among them, bifunctional developing dyes are applied to the object by methods such as drip casting, spraying, and immersion dyeing;

[0022] The objects include most non-permeable objects and some semi-permeable objects.

[0023] The advantages and benefits of this invention are as follows:

[0024] This invention provides a material that can be used for fingerprint imaging.

[0025] First, in the initial stage, the researchers successfully developed latent fingerprints on non-permeable objects using the prepared material. To further optimize the process, the material was prepared into a suspension using water as a solvent. By adding an appropriate amount of cationic surfactant (benzalkonium chloride), stable micelle groups were formed in the aqueous solution and wrapped around the surface of Prussian blue particles. This caused repulsion between electrons, achieving uniform dispersion of the particles and enabling better development. The process can employ various development methods, such as drop casting, spraying, or immersion dyeing, to develop latent fingerprints or blood fingerprints.

[0026] Secondly, the Prussian blue material in this invention is a hollow framework compound with strong adsorption capacity. When it binds to small molecule proteins in the fingerprint, it is firmly fixed to the fingerprint lines due to the common hydrophobic interaction between the substances and the van der Waals forces between the molecules.

[0027] Third, the fingerprint developing solution provided by this invention is mainly aqueous and is a small-particle suspension. Compared with traditional fingerprint developing agents or traditional blood developing reagents, it is green, environmentally friendly, safe, and odorless. Furthermore, it has minimal impact on the biological information in fingerprints, does not cause damage or denaturation of DNA in fingerprint residue, and poses no harm to the health of users.

[0028] Fourth, the fingerprint developing agent provided by this invention works by binding to molecular proteins in latent fingerprints and blood fingerprints. Therefore, it is applicable to most latent fingerprints and blood fingerprints, as well as most non-permeable objects and some semi-permeable objects. It is a bifunctional developing agent based on protein targeting.

[0029] This invention utilizes water as a solvent, Prussian blue as nanoparticles, and benzalkonium chloride as a dispersant to develop a protein-targeting blue developing dye. This dye readily binds to small molecule proteins and can be used to develop blood fingerprints or latent fingerprints containing oils, avoiding the toxicity of traditional blood fingerprinting reagents and significantly reducing safety risks for users. The latent fingerprint developing method provided by this invention features high sensitivity, fast development speed, blue color development, and high contrast against a red background. It can target and develop molecular proteins in fingerprints without reacting with other substances, and its framework structure does not damage DNA in fingerprints. It is suitable for developing fingerprints on various non-permeable substrates. This reagent is environmentally friendly, portable, economical, and poses no potential threat to the health and safety of users. Attached Figure Description

[0030] Figure 1 This is a SEM image of the Prussian blue powder used in this invention.

[0031] Figure 2 This is a flowchart illustrating the optimized route and application process of the Prussian blue developing dye of the present invention.

[0032] Figure 3 The developing state (x40) of the latent fingerprint after applying the developing dye of the present invention to a biological microscope.

[0033] Figure 4 This is an image showing the effect of a latent fingerprint appearing on a silicon wafer.

[0034] Figure 5 This is an image showing the effect of latent fingerprints appearing on a white ceramic tile.

[0035] Figure 6 This is an image showing the effect of latent fingerprints appearing on a white painted wooden board.

[0036] Figure 7 This is an image showing the effect of latent fingerprints appearing on a white enamel object.

[0037] Figure 8 This is an image showing the latent fingerprint effect on a coin.

[0038] Figure 9 This is an image showing the effect of latent fingerprints appearing on a brass cartridge case.

[0039] Figure 10 This is an image showing the effect of latent fingerprints appearing on an aluminum foil object.

[0040] Figure 11 This is an image showing the effect of latent fingerprints appearing on a white leather object.

[0041] Figure 12 Image of a stainless steel object before a blood fingerprint appears.

[0042] Figure 13 Image showing the effect of blood fingerprints appearing on a stainless steel object.

[0043] Figure 14 Image of a blood fingerprint on an aluminum foil object before it appears.

[0044] Figure 15 Image showing the effect of blood fingerprints appearing on an aluminum foil object.

[0045] Figure 16 Image of a blood fingerprint on an enamel object before it appears.

[0046] Figure 17 Image showing the effect of blood fingerprints appearing on an enamel object.

[0047] Figure 18Image of a blood fingerprint on a lacquered wooden board before it appears.

[0048] Figure 19 The image shows the effect of blood fingerprints appearing on a lacquered wooden board. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0050] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0051] The Prussian blue nanoparticles used in the following examples are commercially available Prussian blue (Tianjin Zhonglian CAS: 14038-43-8). Figure 1 This is a SEM image of Prussian blue powder.

[0052] Example 1: Preparation and Use of Bifunctional Developing Dye

[0053] Water and benzalkonium chloride were added to Prussian blue nanoparticles and stirred to obtain Prussian blue aqueous solution, wherein the mass percentage of Prussian blue nanoparticles was 2% and the mass percentage of benzalkonium chloride was 0.2%.

[0054] The obtained Prussian blue aqueous solution is dripped or sprayed onto the object and left to stand. Under ambient light, the blood fingerprints or latent fingerprints containing oil on the object turn blue under the action of the developing solution.

[0055] Figure 2 An optimized route and application flowchart for Prussian blue developing dye.

[0056] Figure 3 The latent fingerprint is developed under a biological microscope after being coated with a developing dye (x40).

[0057] Example 2

[0058] The bifunctional developing dye prepared in Example 1 was dropped onto silicon wafers, white ceramic tiles, white painted wooden boards, white enamelware, coins, brass cartridge cases, aluminum foil sheets, and white leather objects. After standing, the latent fingerprints turned blue under the action of the developing solution.

[0059] Figure 4 This is an image showing the effect of a latent fingerprint appearing on a silicon wafer.

[0060] Figure 5 This is an image showing the effect of latent fingerprints appearing on a white ceramic tile.

[0061] Figure 6 This is an image showing the effect of latent fingerprints appearing on a white painted wooden board.

[0062] Figure 7 This is an image showing the effect of latent fingerprints appearing on a white enamel object.

[0063] Figure 8 This is an image showing the latent fingerprint effect on a coin.

[0064] Figure 9 This is an image showing the effect of latent fingerprints appearing on a brass cartridge case.

[0065] Figure 10 This is an image showing the effect of latent fingerprints appearing on an aluminum foil object.

[0066] Figure 11 This is an image showing the effect of latent fingerprints appearing on a white leather object.

[0067] Example 3

[0068] The bifunctional developing dye prepared in Example 1 was applied to stainless steel, aluminum foil, enamel, and painted wooden surfaces respectively. After standing, the blood fingerprint turned blue under the action of the developing solution.

[0069] Figure 12 Image of a stainless steel object before a blood fingerprint appears;

[0070] Figure 13 Image showing the effect of blood fingerprints appearing on a stainless steel object.

[0071] Figure 14 Image of a blood fingerprint on an aluminum foil object before it appears;

[0072] Figure 15 Image showing the effect of blood fingerprints appearing on an aluminum foil object.

[0073] Figure 16 Image of a blood fingerprint on an enamel object before it appears;

[0074] Figure 17 Image showing the effect of blood fingerprints appearing on an enamel object.

[0075] Figure 18 Image of a blood fingerprint on a lacquered wooden board before it appears;

[0076] Figure 19 The image shows the effect of blood fingerprints appearing on a lacquered wooden board.

[0077] Comparative Example

[0078] During the preparation process, nonionic surfactants (Tween 20 and Tween 40), anionic surfactants (sodium dodecylbenzenesulfonate and sodium dodecyl sulfate), and cationic surfactants (hexadecyltrimethylammonium bromide) were added for control experiments. With concentrations ranging from 0.05% to 1%, the synthesized Prussian blue suspensions exhibited light-colored latent fingerprints or failed to adhere to the latent fingerprint surface. The experiments demonstrated that the surfactants of the above types and concentration ranges could not form stable micelle clusters to disperse the Prussian blue suspension.

[0079] Prussian blue, a porous framework compound, achieves targeted development of different fingerprints on different objects through adsorption staining. In terms of development effect, as a small-particle suspension, this reagent exhibits superior color development and adsorption capacity compared to traditional developing reagents such as carbon ink. As a blood fingerprint developing reagent, it is safer and more environmentally friendly than traditional blood fingerprint developing reagents. Regarding development time, the optimized fingerprint developing dye controls the development time to approximately 5 seconds, reducing the development time by 83%, with the required development time for blood fingerprints between 20 and 30 seconds. In terms of operational safety, the reagent's components pose no harm to the health of users and are easier to handle. Regarding its impact on biological evidence, no damage or destruction of DNA has been found with Prussian blue, making it more conducive to the extraction of biological evidence from crime scenes. Because this developing reagent is simple to prepare, environmentally friendly, safe, and inexpensive, it is convenient for practical application at crime scenes. Based on its hollow framework structure, this material is easy to design and construct, and can be used for directional hybridization to synthesize novel materials, providing enormous development space and application prospects for the field of forensic fingerprint development.

[0080] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. Application of Prussian blue in the development of latent and blood fingerprints.

2. A bifunctional developing dye, comprising the following components: Prussian blue nanoparticles, a cationic surfactant, and water, wherein the Prussian blue nanoparticles constitute 0.5%-6% by mass in the bifunctional developing dye. The cationic surfactant has a mass percentage content of 0.1-1%.

3. The bifunctional developer according to claim 2, characterized in that, The cationic surfactant is benzalkonium chloride.

4. A method for preparing the bifunctional developing dye according to claim 2 or 3, comprising the following steps: adding water and a cationic surfactant to Prussian blue nanoparticles, mixing well to obtain Prussian blue aqueous solution (Prussian blue nanoparticle suspension), i.e., bifunctional developing dye.

5. The method according to claim 4, characterized in that, The Prussian blue nanoparticles have a particle size of 40nm-60nm; The mass percentage of Prussian blue nanoparticles in the obtained bifunctional developing dye is 0.5%-6%. The mass percentage of the cationic surfactant can be 0.1%-1%; The cationic surfactant is benzalkonium chloride.

6. A method for developing latent fingerprints and / or blood fingerprints, comprising: applying the bifunctional developing agent as described in claim 2 or 3 to a subject, allowing it to stand, and under ambient light, the blood fingerprint or grease-containing latent fingerprint on the subject turns blue under the action of the developing solution, thereby realizing the development of the blood fingerprint or grease-containing latent fingerprint on the subject.

7. The method of claim 6, wherein, The bifunctional developing dye is applied to the object using drop casting, spraying, and immersion dyeing methods. The objects include most non-permeable objects and some semi-permeable objects.

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