Fingerprint Detection Research Articles

Comparative upconversion emission studies in AF3: Tm3+/Yb3+ (A=La, Y and Gd) phosphor for latent fingermarks detection

In this work the effect of change of host lattice on upconversion emission properties of Tm3+/Yb3+ doped/codoped fluoride upconversion phosphor particle with host variations is discussed. Lanthanum (La), yttrium (Y) and gadolinium (Gd) based fluoride hosts are selected and Tm3+/Yb3+ ions combination is incorporated via chemical co-precipitation method. The structural and optical properties of developed systems is studied through FE-SEM, XRD, FTIR, Thermogravimetric analysis and visible upconversion emission. Further, these samples were utilised for latent fingermarks detection on different difficult surfaces. Results obtained are appreciable for security and forensic detection purposes.

Kilogram-scale synthesis of carbon dots with high-efficiency full-color solid-state fluorescence using an aggregation-induced emission strategy

Carbon dots (CDs), one of the most promising luminescent nanomaterials, have attracted widespread concern due to their unique optoelectronic properties and widespread application. However, mass production of solid-state CDs with highly efficient full-color emission has rarely been reported, severely limiting their practical application in solid-state lighting and displays. Here, using an aggregation-induced emission (AIE) strategy, full-color solid-state fluorescent (SSF) CDs with quantum yields (QYs) of up to 55.3–27.9% have been prepared on a kilogram scale through one-step microwave-assisted pyrolysis of the same precursors. Detailed structure–property studies demonstrate that the SSF of CDs is derived from the suppression of surface carboxyl group motions and the decrease of the non-radiative rate in their aggregated state, and that their tunable emission is attributed to the excessive fluorescence resonance energy transfer (FRET) induced by the increasing number of aromatic rings on CD surfaces. Therefore, these CDs exhibit both the AIE enhancement and red shift throughout the entire visible spectrum in the solid state. Finally, because of their excellent AIE properties, these highly efficient SSF CDs have been applied to pattern encryption, large-area luminescent fibrous membranes (LFMs), light-emitting diodes (LEDs), and fingerprint detection.

Molecular Fingerprint Detection with a Mid-infrared Guided-Mode Resonance

Molecular Fingerprint Detection with a Mid-infrared Guided-Mode Resonance

A new strategy to boost luminescent markers for LFP detection and anti-counterfeiting applications using flux assisted BaLa2ZnO5:Eu3+ phosphor

A red-emitting BaLa2ZnO5:Eu3+ nanophosphors (BLZO:Eu NPs) are successfully prepared via combustion method with the aid of variable fluxes. BLZO:Eu NPs without and with flux materials how they differ in terms of their structure, morphology, PL characteristics were discussed. Effect of these flux-materials on the crystal structure found to be minimal. However, the morphology, PL intensity and photoluminescence (PL) performance are all affected by the inclusion of these flux-materials. When compared to other fluxes, the NH4F flux-material more specifically may clearly increase the emission intensity by 2.5 times. Also it provides the best optimization in terms of quantum yield (QY). By tuning the flux material, the colour of the phosphor changes from orange to pure red. The optimized BLZO:3Eu/NH4F NPs performs better luminous labelling platform for latent fingerprint detection and anti-counterfeiting applications. Overall findings overwhelmingly support the employment of the BLZO:3Eu/NH4F phosphor in photonic devices, dermatoglyphics and data security applications.

Surface-Assisted Laser Desorption/Ionization Mass Spectrometry Analysis of Latent Fingermarks Using Greenly Synthesized Silver Nanoparticles

Advances in nanotechnology have contributed to many innovative approaches in the forensic sciences, including the development of new techniques and protocols for latent fingermark detection. Among other nanomaterials, metal-based nanoparticles have been explored as suitable developers for fingermarks present on surfaces that challenge traditionally established methods. The present study explored, for the first time in the forensic science literature, the application of greenly synthesized silver nanoparticles (AgNPs) for latent fingermark surface-assisted laser desorption/ionization mass spectrometry (SALDI MS) analysis. A leaf extract of a native plant from the Cerrado biome was used for green synthesis of the AgNPs, and their hydrodynamic diameter, polydispersity index (PdI), and Zeta potential values were evaluated. Latent fingermarks were produced by three distinct donors and treated with α-CHCA matrix or AgNP suspension and were further investigated using commercial matrix assisted laser desorption/ionization (MALDI)-TOF MS equipment in the m/z range of 100–1000. Characterization results of the AgNPs indicated an average hydrodynamic diameter of 25.94 ± 0.30 nm, a PdI of 0.659 ± 0.085, and a Zeta potential of −33.4 ± 2.6 mV. The silver ions detected showed a relative intensity at least 20× higher for greenly synthesized AgNPs than for AgNO3 suspension, which may be advantageous for the detection of molecular species, especially olefins, present in forensic traces. The AgNP-based SALDI MS approach for the analysis of latent fingermarks showed intense ions at m/z 106.9, 215.8, and 322.7, referring to silver cation species that have been reported as important internal calibrants. The detection of components from endogenous and exogenous sources in latent fingermarks was achieved using the present approach. Greenly synthesized AgNPs may offer a new cost-effective, eco-friendly, and easily scaled up method for application in the chemical analysis of fingermarks.

ESIPT‐AIE Active Schiff Base Fluorescent Organic Nanoparticles Based on 2‐(2‐(4‐(4‐bromo Phenyl) Thiazol‐2‐yl)Vinyl)Phenol (BTVP) Utilized as a Multi‐Functional Fluorescent Probe

AbstractThe present study reports the synthesis and characterization of Aggregation‐Induced Emission (AIE) – Excited‐state intramolecular proton transfer (ESIPT) active 2‐(2‐(4‐(4‐bromo phenyl) thiazol‐2‐yl)vinyl)phenol (BTVP). The AIE properties of BTVP in Acetone/Water solution are investigated, and fluorescent organic nanoparticles (FONs) (sizes ranging from 150–200 nm) are prepared in various water fractions (fH2O). The established visco‐chromic property suggests that the restriction of intramolecular rotation is responsible for the AIE‐ESIPT behavior of the molecule, providing a means to sense viscosity. The synthesized FONs act as fluorescence chemosensors to detect Al3+ ions via a photoinduced electron transfer (PET) mechanism. Job's, Benesi–Hildebrand method, and 1HNMR titration confirm the 1:1 binding of BTVP with the metal ion. Studies on the emission concerning pH reveal the high stability of FONs over a broad range of pH, and a gradual change in the emission wavelength for the BTVP‐Al3+ complex (BTVP‐Al) is observed, providing a means to sense pH ranging from 2–8. The solid‐state photoluminescence of BTVP is used for latent fingerprint detection, demonstrating its efficiency in detecting both primary and secondary information. Additionally, both BTVP FNOs and BTVP‐Al are used in cell imaging, where specific nuclear staining with BTVP‐Al and cytoplasm staining with BTVP are observed.

Pioneering ginger juice extract mediated synthesis of magnesium indate nanoparticles

Magnesium indate nanoparticles were synthesized via a biomediated route using ginger extract as a reducing agent followed by calcination. The Bragg reflections confirm the formation of an orthorhombic crystal structure with space group Imma. This was in turn confirmed through Rietveld refinement. The crystallite size and other structural parameters were calculated. Agglomerated irregularly sized and irregularly shaped nanoparticles were observed. The direct band gap was found to be 3.16 eV. Photoluminescence analysis was performed with excitation at 250 nm. The photoluminescence intensity and CIE values drop in the blue region of the visible spectrum. The correlated color temperature was found to be 2748 K. Further, the powder dusting method was used to collect latent fingerprints on porous and nonporous surfaces. The synthesized magnesium indate results in well-resolved ridge patterns that can be used to identify latent fingerprints with clarity. From all these results, the present synthesized magnesium indate nanoparticles might find application in display technology as a blue nanophosphor material and for latent fingerprint detection in forensic science.

Optical thermometry, latent fingerprint detection and anti-counterfeiting based on upconversion emission in Ho3+/Yb3+ doped KYF4 nanoparticles

The structural, morphological, and optical properties of the KYF4:Ho3+/Yb3+ upconversion nanoparticles were investigated in this work. In the upconversion emission studies, emissions at 544 nm, 657 nm, and 740 nm resulting from the transitions 5F4 (5S2) → 5I8, 5F5 → 5I8 and 5F4(5S2) → 5I7, respectively, of the Ho3+ ion were observed. Temperature sensitivity was determined from temperature-dependent upconversion spectra, and it was found to be 1.32% K−1 for the synthesized upconversion nanoparticles. Additionally, the nanoparticles were utilized to detect latent fingerprints on the glass, and the recorded images show good contrast. Upconversion nanoparticles were also used to create the invisible ink, and the written words were subsequently recorded using upconversion emission mode.

Nanocomposites of PVA-PVP and l-ascorbic acid modified ZnO:Fe via ultrasonic irradiation as a green technique: Latent fingerprint detection, food packing and anti-bacterial applications

Nanocomposites of PVA-PVP and l-ascorbic acid modified ZnO:Fe via ultrasonic irradiation as a green technique: Latent fingerprint detection, food packing and anti-bacterial applications

Highly efficient latent fingerprint detection from NaYF4:Eu down-shifting microparticles

Each person's latent fingerprints (LFP) are unique and hardly change, so LFP detection provides essential clues in forensic science. Currently, the powder dusting method is being promoted for viewing LFP due to its environmental safety; however, its low efficiency, low sensitivity, and toxicity are drawbacks, restricting its applications. To overcome these points, we proposed a NaYF4:Eu3+ downshifting microparticle (DSMPs) phosphor synthesized by a hydrothermal method with intense emission of ∼590–620 nm under excitation of 395 nm. We systematically studied the effect of synthesis conditions such as chelator, reaction time, temperatures, and doping concentrations on the structural, luminescent properties, and decay curves. The obtained results reveal that the crystal phase and particle morphology strongly depend on the reaction temperature. The emission properties of NaYF4:Eu3+ DSMPs can be significantly improved by changing the reaction temperatures and Eu doping contents. The optimized DSMPs with the most intense luminescent intensity were achieved when the phosphors were prepared at 180 οC for 24 hours, the rare earth stearate/oleic acid ratio of 1:24, and Eu doping amount of 10 mol%. This finding contributes to the suppression of substrate interference in LFP detection. The prepared NaYF4:Eu3+ DSMPs address the earlier limitations and show good potential for LFP detection.

Frequency selective fingerprint sensor: the Terahertz unity platform for broadband chiral enantiomers multiplexed signals and narrowband molecular AIT enhancement

Chiral enantiomers have different pharmacological and pharmacokinetic characteristics. It is important to strictly detect chiral component for avoiding being harmful to the human body due to side effects. Terahertz (THz) trace fingerprint detection is essential because the molecular vibrations of various biological substances such as chiral enantiomers are located in THz range. Recent reported enhanced trace fingerprint technologies have some drawbacks. For instance, multiplexing technology suffered from narrow operation range and limitation by frequency resolution of commercial THz time domain spectroscopy; Absorption induced transparency (AIT) identification for narrowband molecular oscillations suffered from random resonance frequency drift due to fabrication error. In this paper, we proposed frequency-selective fingerprint sensor (FSFS), which can experimentally achieve enhanced trace fingerprint detection by both broadband multiplexing technology and robust AIT identification. Such FSFS is based on polarization independent reconfiguration metasurfaces array. Broadband absorption lines of trace-amount chiral carnitine were boosted with absorption enhancement factors of about 7.3 times based on frequency-selective multiplexing at 0.95–2.0 THz. Enhanced trace narrowband α-lactose fingerprint sensing can be observed at several array structures with absorption enhancement factors of about 7 times based on AIT, exhibiting good robustness. The flexibility and versatility of proposed FSFS has potential applications for boosting trace chiral enantiomer detection as well as diversity of molecular fingerprints identification by both multiplexing and AIT.

Single-molecule multi-target fluorescent imaging for latent fingerprints based on aggregation-induced emission

Existing latent fingerprint developers achieve marvelous progress during the past decades. However, most of these methods mainly consider single target substance, which may face difficulties in latent fingerprint imaging when the corresponding substance is absent from latent fingerprint traces. To alleviate this issue, we propose a novel single-molecule multi-target green fluorescent probe, TPE-NI-NHS, which could target both lipids and amino acids through physical adsorption and chemically bonding under mild conditions, respectively. Specifically, tetraphenylethylene and active ester group in TPE-NI-NHS are connected at two ends of the naphthalimide core, which provide perfect aggregation-induced emission, accurate and quick reaction with amino acids, lipophilic properties, and green fluorescence emission. As expected, TPE-NI-NHS achieves green fluorescent imaging for latent fingerprints contained different contents of lipids and amino acids with high quality, high sensitivity, and high contrast under mild conditions. In summary, TPE-NI-NHS developer provides multiple targeting features, novel imaging principles and mild imaging process to latent fingerprint detections.

Multimodal Optically Nonlinear Nanoparticles Exhibiting Simultaneous Higher Harmonics Generation and Upconversion Luminescence for Anticounterfeiting and 8‐bit Optical Coding

AbstractNonlinear optical materials are essential in areas such as nanophotonics, optical information processing, and biomedical imaging. However, nanomaterials employed for these diverse applications to date are efficient only for one type of nonlinear optical activity. Herein, the first multimodal nonlinear optically active class of nanomaterials based on lanthanide‐doped lithium niobate nanoparticles, which simultaneously exhibit unprecedentedly efficient second and third harmonic generation, as well as up‐conversion photoluminescence, is reported. These dielectric nanoparticles retain their high nonlinear optical conversion efficiency both as powder and as aqueous colloidal solution. The high stability also allows for the fabrication of optically active biocompatible micron‐sized fibers and polymer‐based 3D‐printable objects, as well as for fingerprint detection. Finally, the first 8‐bit coding platform purely based on multimodal nonlinear optical activity originating from different parametric and nonparametric processes is demonstrated, showcasing the technological potential of these materials for both anti‐counterfeiting and advanced optical information processing.

Effect of Exposure Concentration and Growth Conditions on the Association of Cerium Oxide Nanoparticles with Green Algae.

The increasing release of engineered nanoparticles (NPs) into aquatic ecosystems makes it crucial to understand the interactions of NPs with aquatic organisms, such as algae. In this study, the association of CeO2 NPs with unicellular algae (Raphidocelis subcapitata) and changes to the cellular elemental profile were investigated using three exposure concentrations (1, 50, and 1000 µg CeO2/L) at two different algal growth conditions-exponential and inhibited growth (1% glutaraldehyde). After a 24 h-exposure, algal suspensions were settled by gravity and CeO2-NP/algae association was analyzed by single-cell inductively coupled plasma quadrupole mass spectrometry (sc-ICP-QMS) and ICP time-of-flight MS (sc-ICP-TOFMS). Concurrent detection of the cellular fingerprint with cerium indicated NP association with algae (adsorption/uptake) and changes in the cellular elemental profiles. Less than 5% of cells were associated with NPs when exposed to 1 µg/L. For 50 µg/L exposures in growing and inhibited cell treatments, 4% and 16% of cells were associated with CeO2 NPs, respectively. ICP-TOFMS analysis made it possible to exclude cellular exudates associated with CeO2 NPs due to the cellular fingerprint. Growing and inhibited cells had different elemental profile changes following exposure to CeO2 NPs-e.g., growing cells had higher Mg and lower P contents independent of CeO2 concentration compared to inhibited cells.

Upconversion luminescence based temperature sensing properties and anti-counterfeiting applications of GdNbO4:Tm3+/Yb3+ phosphor

Pure monoclinic phase GdNbO4:Tm3+/Yb3+ phosphor was prepared using solid state reaction method for upconversion emission, optical thermometry, latent fingerprints visualization and anti-counterfeiting applications. The prepared phosphor exhibits colour tunability with temperature variation (from blue to almost white) and good suppression of thermal quenching. The temperature sensing characteristic from thermally and non-thermally coupled levels of Tm3+ ion were investigated using the fluorescence intensity ratio (FIR) approach. The result shows that the sensitivity for non-thermally coupled level is about ∼ 45 times higher than thermally coupled level. Latent fingerprint detection on various surfaces and anti-counterfeiting ink application were also shown upon 980 nm laser diode excitation. Above results indicate that the prepared GdNbO4:Tm3+/Yb3+ phosphor have applicability in the field of frequency upconversion, optical thermometry, color tunable devices, latent fingerprint visualization and anti-counterfeiting applications.

A novel process for developing a quantitative chromatographic fingerprint analysis method based on analytical quality by design: A case study of Xiaochaihu capsules

In this study, an improved Analytical Quality by Design (AQbD) process was proposed to establish quantitative fingerprints of Chinese medicines. A quantitative fingerprint method for the strong polar components in Xiaochaihu capsules was developed as an example. Different method evaluation indicators were used to characterize this method, and these indicators were measured at different stages of quantitative fingerprint development. Through this method, the difficulty in determining common peaks in the early stage of quantitative fingerprint development is eliminated. The method parameters that needed to be optimized were the mobile phase gradient conditions, column temperature and flow rate through the Ishikawa diagram. Single-factor experiments were used to determine some parameters. Definitive screening design (DSD) experiments were used to optimize critical method parameters (CMPs). The common peaks were determined, and indices were optimized. The critical method attributes (CMAs) were the resolution of guanosine, the percentage of common peak to the total peak area, retention time of the last peak and the common peak number. A stepwise regression method was used to build quantitative models for critical method attributes and critical method parameters. The method operable design region (MODR) was calculated by the experimental error simulation method and successfully verified. After the analysis conditions were optimized, four components, uridine, adenine, 5-hydroxymethylfurfural, and guanosine, were quantitatively determined. There were 7 common peaks in the fingerprints. The common peak area accounted for 90.64%. Both fingerprint and quantitative detection analysis methods were methodologically validated. The new AQbD process proposed in this study can be potentially applied to develop other Chinese medicines fingerprint methods.

NIR activated Er3+/Yb3+ doped LiYF4 upconverting nanocrystals for photothermal treatment, optical thermometry, latent fingerprint detection and security ink applications

This work reports the upconversion (UC) emission studies on Er3+/Yb3+ doped LiYF4 nanoparticles for radiation-to-heat conversion, optical thermometry using thermally coupled and uncoupled levels, latent fingerprint detection and security ink applications. LiYF4:Er3+/Yb3+ nanoparticles have been synthesized using the thermal decomposition reaction method using oleic acid and 1-octadecane as reaction medium. Crystal phase, crystallinity and size have been investigated using XRD and TEM techniques. UC emission ability of the prepared phosphor was tested using a CW laser source having 980 nm excitation. Under 980 nm excitation, synthesized nanoparticles have shown emission bands around 522 nm, 550 nm and 668 nm corresponding to transitions from 2H11/2, 4S3/2, and 4F9/2 levels to 4I15/2 level of Er3+ ions, respectively. Further, the number of photons involved in the UC process has been calculated using a pump power UC study. Decay time analysis of the most intense green (550 nm) and red (668 nm) emission bands is performed to study the emission dynamics. A study on the radiation-to-heat conversion phenomenon has revealed photothermal conversion efficiency of 29.5% which is important for photothermal therapy. The green and red UC emissions from the sample under stimulation at very low pump power (35 mW) are used to study the optical temperature sensing characteristics. The findings of this study suggest that the Er3+/Yb3+ co-doped LiYF4 phosphor may be particularly useful for creating NIR to visible upconversion and temperature sensing. Moreover, latent fingerprint detection and security ink for anti-counterfeiting applications are also demonstrated.

Tris(2,2'-bipyridyl)ruthenium (II) complex as a universal reagent for the fabrication of heterogeneous electrochemiluminescence platforms and its recent analytical applications.

In recent years, electrochemiluminescence (ECL) has received enormous attention and has emerged as one of the most successful tools in the field of analytical science. Compared with homogeneous ECL, the heterogeneous (or solid-state) ECL has enhanced the rate of the electron transfer kinetics and offers rapid response time, which is highly beneficial in point-of-care and clinical applications. In ECL, the luminophore is the key element, which dictates the overall performance of the ECL-based sensors in various analytical applications. Tris(2,2'-bipyridyl)ruthenium (II) complex, Ru(bpy)32+, is a coordination compound, which is the gold-standard luminophore in ECL. It has played a key role in translating ECL from a "laboratory curiosity" to a commercial analytical instrument for diagnosis. The aim of the present review is to provide the principles of ECL and classical reaction mechanisms-particularly involving the heterogeneous Ru(bpy)32+/co-reactant ECL systems, as well as the fabrication methods and its importance over solution-phase Ru(bpy)32+ ECL. Then, we discussed the emerging technology in solid-state Ru(bpy)32+ ECL-sensing platforms and their recent potential analytical applications such as in immunoassay sensors, DNA sensors, aptasensors, bio-imaging, latent fingerprint detection, point-of-care testing, and detection of non-biomolecules. Finally, we also briefly cover the recent advances in solid-state Ru(bpy)32+ ECL coupled with the hyphenated techniques.

Synergetic effects of boron nitride with waste zirconia: Evaluation of instantaneous fingerprint detection and mechanical properties for biomedical applications

Herein, present study mainly focuses on the synthesis and characterizations of boron nitride reinforced waste zirconia (wZrO2) with different concentrations. Composites were prepared via a scalable solid-state reaction method. Various physical parameters such as density, ionic concentration, polaron radius, and field strength were evaluated. XRD results reveal crystalline nature with a major phase of tetragonal zirconia and as boron nitride is reinforced, the tetragonal transforms into a monoclinic zirconia. Interconnected spherical grains and nanosheets were observed using FESEM. Mechanical characterizations revealed the highest compressive strength of 266 MPa. The latent fingerprints were visualized using a composite on different surfaces, implementing the powder dusting and solution techniques. MTT assay was performed and revealed good biocompatible nature. These results reveal that composite is suitable for fabrication of bioceramics with acceptable mechanical and biological performances. The composite can also be utilized for latent fingerprint detection in forensic science.

Synthesis and Characterization of MC/TiO2 NPs Nanocomposite for Removal of Pb2+ and Reuse of Spent Adsorbent for Blood Fingerprint Detection.

The removal of toxic heavy metals from wastewater through the use of novel adsorbents is expensive. The challenge arises after the heavy metal is removed by the adsorbent, and the fate of the adsorbent is not taken care of. This may create secondary pollution. The study aimed to prepare mesoporous carbon (MC) from macadamia nutshells coated with titanium dioxide nanoparticles (TiO2 NPs) using a hydrothermal method to remove Pb2+ and to test the effectiveness of reusing the lead-loaded spent adsorbent (Pb2+-MC/TiO2 NP nanocomposite) in blood fingerprint detection. The samples were characterized using SEM, which confirmed spherical and flower-like structures of the nanomaterials, whereas TEM confirmed a particle size of 5 nm. The presence of functional groups such as C and Ti and a crystalline size of 4 nm were confirmed by FTIR and XRD, respectively. The surface area of 1283.822 m2/g for the MC/TiO2 NP nanocomposite was examined by BET. The removal of Pb2+ at pH 4 and the dosage of 1.6 g/L with the highest percentage removal of 98% were analyzed by ICP-OES. The Langmuir isotherm model best fit the experimental data, and the maximum adsorption capacity of the MC/TiO2 NP nanocomposite was 168.919 mg/g. The adsorption followed the pseudo-second-order kinetic model. The ΔH° (-54.783) represented the exothermic nature, and ΔG° (-0.133 to -4.743) indicated that the adsorption process is spontaneous. In the blood fingerprint detection, the fingerprint details were more visible after applying the Pb2+-MC/TiO2 NP nanocomposite than before the application. The reuse application experiments showed that the Pb2+-MC/TiO2 NP nanocomposite might be a useful alternative material for blood fingerprint enhancement when applied on nonporous surfaces, eliminating secondary pollution.