So that criminals nowhere to hide! \”JACS\”: 30 seconds! AIE let potential fingerprint visualization faster, clearer

Fingerprint, i.e., a ridge protrusion on the skin. As the person\’s fingerprint is the interaction of genetic and environmental impacts, and therefore everyone has a fingerprint, but not the same. As the fingerprint repetition rate is extremely small, about one minute 15 billion, it is referred to as \”human identity.\” Latent fingerprint (Latent fingerprints, LFP) due to finger sweat secreted sweat pores covered by the finger so they touch object is formed. Even when thoroughly dry hands, it is likely he will stay in place LFP contact, especially the smooth surface of the object, LFP is the most common crime scene fingerprint type, almost invisible to the naked eye. Therefore, LFP development is critical to solving criminal cases. LFP visualization methods currently used have obvious limitations, such as toxicity, may result in damage to the LFP, less suitable for the scene, and often less than level 3 and high contrast resolution (level 3 microscopic fingerprint details is For more information, including the shape of the hole and the ridge width of the ridge and the edge) of the developing effect. Based on the above issue, Wuhan National Research Center for Optoelectronics Professor Lee Chong with Huazhong University of Science and Technology Professor Zhu Mingjiang cooperation [123 ], developed a new molecule AIE LFP for visualization, and prepared with simple, non-toxic, high resolution (LEVEL 3) and the characteristics suitable for the multi-scene, able to form a clear fingerprint pattern with high contrast and resolution of the within 30 s. Related outcomes to \”Real-Time Fluorescence In Situ Visualization of Latent FingerprintsExceeding Level 3 Details Based on Aggregation-Induced Emission\” was published in \” JACS \” on.

Analytical graphic

1. Synthesis and Characteristics of TPA-1OH the AIE

FIG. 1 (a) Synthesis of TPA-1OH schematic. (B) TPA-1OH normalized in water (10 M) and a solid of the absorption and emission spectra. (C) in water and EA / water mixture in the emission spectrum of TPA-1OH, EA content of 99%. Illustration: irradiation at 365 nm (5μM), EA / water mixture fluorescence photograph EA scores were 0% and 99% of the TPA-1OH.

2, TPA-1OH mechanism of Visualization and applied to the LFP

FIG. 2 (a) 405 nm irradiation at aqueous solution at different concentrations of TPA-1OH developing the LFP RGB true color images (scale bar: 5 mm). (B) the text \”LFP\” fluorescence pictures (irradiation at 405 nm), written in the common LFP different substances and sprayed with an aqueous solution of TPA-1OH. (C) using an aqueous solution of TPA-1OH LFP FIG developed mechanismResearchers first synthetic molecules AIE LPF for imaging. To assess the effect of TPA-1OH LFP development of the foil with the fingerprint immersed in an aqueous solution at different concentrations of TPA-1OH 1 minute. Irradiation at 405 nm, with increasing dye concentration, gradually visible fingerprint. Fingerprint image dye at lower concentrations (5 and 10 M) is not obvious, but clearly visible at 30 and 50 M (FIG. 2a) of the dye concentration. And

, toxicity tests show that no toxicity at 0,10 and 30 uM time, low toxicity at 50μM. Next, in order to verify which component LFP can be identified and combined with TPA-1OH, using a solution mainly composed of LFP, the metal plate wrote the character \”LFP.\” The results indicate that only lipid component written by \”LFPs\” emits strong fluorescence pattern, and clearly visible, shows that the probe does stained lipid compound (FIG. 2b) LFPs in. When contacted with an aqueous solution of TPA-1OH LFPs, lipid molecules adhering to LFPs secretions, which is probably due to the hydrophobic lipid secretion LFPs phase – and hydrophobic interaction lipophilic end TPA-1OH caused . Once the LFPLipid secretion in conjunction with limit intramolecular TPA-1OH molecule can be due to the viscous effect of lipid secretion caused by motion (RIM) and emits strong fluorescence.

3, kinetic studies

on the

FIG. 3 (a) in an aqueous solution of TPA-1OH, irradiation at 405 nm, foil LFP real-time fluorescence in situ developed (dimensions: 5mm). (B) a white circle in the region of the time resolved fluorescence intensity change. (C) passing through the change in fluorescence intensity contrast between fingerprint ridges and furrows green line at different times.Subsequently, researchers conducted a study of dynamics. As shown in FIG 3a, the outline of the fingerprint gradually visible after 3 s, the vein is gradually visible fingerprint, the fingerprint pattern is clearly observed in about 11 s, show convenient in situ imaging capability of TPA-1OH. , The fluorescent intensity rapidly increased first 5 s Figure 3b almost half of the maximum, and then gradually increase. After 30 s, the fluorescence intensity is almost unchanged. Change in signal intensity (Fig. 3c) between the green line across the fingerprint ridges and furrows also

real-time show TPA-1OH developing a clear ridges and green lines of high contrast fingerprint image, shows rapid developability .

FIG. 4 (a) in an aqueous solution of TPA-1OH (dimensions: 5 mm) on different substrates are developed, the whole of LFP true RGB color photographs (under 405 nm irradiation). (B) a developing solution by the TPA-1OH foil, a partial stage LFP on paper and plastic cards, class 2 and class 3 for more information, and the change in fluorescence intensity between the fingerprint ridges and grooves through the green line ( scale bar: 5 mm).Researchers further study of TPA-1OH universal probes, different materials by soaking in TPA-1OH (30μM in water) for 1 minute. The results showed that in different substrates can be imaged well (FIG. 4A), and

Imaging level reaches the level 3 (Figure 4b).

5. TPA-1OH applied to high-resolution imaging of LFP

FIG. 5 micro LFPMorphology, optical imaging and characterized by SEM. (A) bright field image of the region of the ridge portion LFP from a volunteer, and (b) a conventional fluorescence image (target: 10 times). Bright field image of the same area of ​​lipid deposition point of the ridge (c) LFP, (d) traditional fluorescence image and (e) a super-resolution image, which is larger than the magnification of (a) (target: 100 times). SEM images were LFP ridges (f) 600 times, and (g) 5000-fold. (H) (e) of the super-resolution imaging photon count distributions for each location event. Using a single exponential fit to calculate the average number of photons. (I) (e) the overall resolution, determined by the Fourier ring correlation (FRC). The LFP for optical imaging of a sample immersed in an aqueous solution of TPA-1OH. Samples for SEM LFP with water to remove the water-soluble pre-soaked secretions, and then dried at room temperature, and then tested.Finally, in order to obtain more detailed information than the level LFP 3, using super-resolution fluorescence imaging to obtain details of the LFP nanometers. Bright field optical image of the partial region can be identified substantially the LFP (FIG. 6a). After staining TPA-1OH, a conventional fluorescence image can be observed and the sweat pores LFP clear outline (FIG. 6b). It can be seen from the fingerprint deposit number of different sizes of the composition, which is consistent with the image SEM (Fig. 6f and g). Combined super-resolution imaging of fluorescence imaging can visualize lipid deposits higher resolution, and contributes to a better understanding of lipid deposits.

summed In summary, TPA-1OH having hydrophilic – hydrophobic molecular structures which result can be combined with a lipid fingerprint, since the end of the RIM hydrophobic lipid secretions adhering fingerprints formed on a strong red fluorescence. Can be observed within a few seconds to a fingerprint profile, it can be clearly observed fingerprint pattern having a high contrast and resolution within 30 s. It promises to be some obscure and illegible fingerprints indicator to facilitate forensic DNA information extracted suspects. Original link: https: //doi.org/10.1021/jacs.0c00124