Nanoparticle-Enhanced Fluorescence Imaging of Latent Fingerprints Reveals Drug Abuse

A Nanofilm-Based Fluorescent Sensor toward Highly Efficient Detection of Ethephon

Ethephon (ETH) is widely used to promote fruit ripening and improve fruit quality. However, improper use is harmful to human health and to the environmental safety. Therefore, development of the techniques for on-site and at real-time monitoring of ETH is of importance for its safe use. In this work, we developed a nanofilm-based fluorescence film sensor (FFS) and realized highly efficient detection of ETH in vapor phase, where the detection limit (DL) is <0.2 ppb, the response time is less than 10 s, and the interference is almost free. The unusual sensing performance of the sensor was ascribed to the specific binding of the nanofilm to ETH and to its great porosity, which enables efficient adlayer mass transfer, a requirement for high signal-to-noise ratio. Moreover, visualization-based qualitative sensing is also realized. The nanofilm, a key component of the sensor, was prepared at the humid air/DMSO interface. The building blocks used were a specially designed fluorescent o-carborane derivative (CB-2CHO) and a cross-linker BTN possessing three acylhydrazine groups. The nanofilm as prepared is flexible, uniform, thickness tunable, and photochemically super stable. We believe our effort not only addresses the challenging issue of on-site and at real-time detection of ETH but also provides another route for developing new FFSs via sensing film innovation.

Harnessing fluorescent carbon quantum dots from natural resource for advancing sweat latent fingerprint recognition with machine learning algorithms for enhanced human identification

Nowadays, it is fascinating to engineer waste biomass into functional valuable nanomaterials. We investigate the production of hetero-atom doped carbon quantum dots (N-S@MCDs) to address the adaptability constraint in green precursors concerning the contents of the green precursors i.e., Tagetes erecta (marigold extract). The successful formation of N-S@MCDs as described has been validated by distinct analytical characterizations. As synthesized N-S@MCDs successfully incorporated on corn-starch powder, providing a nano-carbogenic fingerprint powder composition (N-S@MCDs/corn-starch phosphors). N-S@MCDs imparts astounding color-tunability which enables highly fluorescent fingerprint pattern developed on different non-porous surfaces along with immediate visual enhancement under UV-light, revealing a bright sharp fingerprint, along with long-time preservation of developed fingerprints. The creation and comparison of latent fingerprints (LFPs) are two key research in the recognition and detection of LFPs, respectively. In this work, developed fingerprints are regulated with an artificial intelligence program. The optimum sample has a very high degree of similarity with the standard control, as shown by the program's good matching score (86.94%) for the optimal sample. Hence, our results far outperform the benchmark attained using the conventional method, making the N-S@MCDs/corn-starch phosphors and the digital processing program suitable for use in real-world scenarios.

Instantaneous High-Resolution Visual Imaging of Latent Fingerprints in Water Using Color-Tunable AIE Pincer Complexes

Instant visualization of latent fingerprints is developed by using a series of water-soluble terpyridine zinc complexes as aggregation-induced emission probes in pure water, under UV light or ambient sunlight. By simply soaking, or spraying with an aqueous solution of the probe, bright yellow fluorescence images with high contrast and resolution are readily developed on various surfaces including tinfoil, glass, paper, steel, leather, and ceramic tile. Remarkably, latent fingerprints can be visualized within seconds including details of whorl and sweat pores. The color of emission can be tuned from blue to orange by modifying the pincer ligands, allowing direct imaging under sunlight. These inexpensive, water-resistant, and color-tunable probes provide a practical approach for latent fingerprints recording and analysis, security protection, as well as criminal investigation in different scenarios.

Unlocking the potential of forensic traces: Analytical approaches to generate investigative leads

Forensic investigation involves gathering the information necessary to understand the criminal events as well as linking objects or individuals to an item, location or other individual(s) for investigative purposes. For years techniques such as presumptive chemical tests, DNA profiling or fingermark analysis have been of great value to this process. However, these techniques have their limitations, whether it is a lack of confidence in the results obtained due to cross-reactivity, subjectivity and low sensitivity; or because they are dependent on holding reference samples in a pre-existing database. There is currently a need to devise new ways to gather as much information as possible from a single trace, particularly from biological traces commonly encountered in forensic casework. This review outlines the most recent advancements in the forensic analysis of biological fluids, fingermarks and hair. Special emphasis is placed on analytical methods that can expand the information obtained from the trace beyond what is achieved in the usual practices. Special attention is paid to those methods that accurately determine the nature of the sample, as well as how long it has been at the crime scene, along with individualising information regarding the donor source of the trace.

Study on the Absorption and Conduction Properties of Vanisulfane in Tobacco

The purposes of this study were to explore the systemic properties of vanisulfane in tobacco plant and to provide a reference for the rational use of vanisulfane in the field. After the tobacco plants were treated by hydroponics and foliar spraying, the contents of vanisulfane in root and stem leaf were detected by high-performance liquid chromatography tandem high-resolution mass spectrometry (UPLC-HRMS), and the position of vanisulfane in root and stem leaf was real-time observed through fluorescence two-photon confocal microscope. UPLC-HRMS results showed that the contents of vanisulfane in root and stem leaf gradually increased with the extension of processing time, and after 12 h treatment, the contents of vanisulfane in root and stem leaf reached the maximum levels of 31.95 and 0.215 mg/kg, respectively. In addition, fluorescence two-photon confocal microscope results showed that vanisulfane could observe in the root and stem leaf. These results showed that vanisulfane had excellent upward and downward of systemic in tobacco plants, which is helpful to guide a reference for the rational use of vanisulfane in the field.

A review on the advancements in chemical examination of composition of latent fingerprint residues

Background

There are notable developments in the field of DNA analysis and recognition, still fingerprint analysis remains the most preferred approach for obtaining substantial forensic evidences. The identification of individuals through pattern comparison has been used through ages, but it becomes less effective when the pattern is blurred, partial in nature or not found in database. Thus, recent advances in analytical techniques over the last decade will provide additional information to the evidence. In the view of forensic investigations, the compilation of individual chemical profiles with the pattern would enhance the evidentiary value of the latent fingerprints.

Main body

The review has been divided into different parts, describing the various influencing factors which affect the chemical composition of a fingerprint, i.e., lifestyle and occupation, age of an individual, types of substrate on which fingerprint is deposited, environmental conditions, contaminants, and the various advanced instrumental techniques utilized till now in the detection of chemical constituents of fingerprint have been discussed.

Conclusion

The present work aims to enlighten the missing gaps of knowledge in elucidating the detailed chemical composition of fingerprints and highlight the various analytical techniques used till date. Though, there are several analytical techniques employed till date to explicate the constituents of fingerprints, detailed information is still lacking. Therefore, advanced future research is need of the hour for identification of the fingerprints and determining their aging kinetics.

Preparation of Novel Magnetic Nanomaterials Based on "Facile Coprecipitation" for Developing Latent Fingerprints (LFP) in Crime Scenes

Recently, the application of novel nanomaterials, especially magnetic nanomaterials in the development of latent fingerprints (LFP), has become the hot focus for forensic scientists and criminal investigators. As a type of recyclable, environment-friendly material, Fe₃O₄ nanoparticles achieve a wonderful effect in visualization of LFP. We first report the synthesis and encapsulation of nano-Fe₃O₄ through "facile coprecipitation", (3-mercaptopropyl)triethoxysilane was covalently embedded into Fe₃O₄ nanoparticles, and the Fe₃O₄ core was encapsulated by the nanosilver to prepare novel magnetic nanomaterials (P-MNP@Ag) with the core-shell configuration. For comparison, the magnetic nanomaterials (S-MNP@Ag) were prepared by surface modification. Their composition, structure, and properties were characterized by SEM, TEM, XRD, IR, XPS, and VSM. Compared with commercially available gold powder, silver powder, bare magnetic powder, and prepared S-MNP@Ag, the development effect of LFP on different objects by using P-MNP@Ag had better performance, which presented the advantages of low background interference, high sensitivity, and clear secondary details in LFP. In the crime scenes of some influential cases, P-MNP@Ag had been applied to the visualization of LFP. The biometric identification of criminal suspects was confirmed through fingerprint comparison, which was highly affirmed by the public security department.

A facile construction of bifunctional core-shell magnetic fluorescent Fe3O4@YVO4:Eu3+ microspheres for latent fingerprint detection

Latent fingerprint recognition technique has received increasing attention because it helps to precisely identify human information for many applications. In this study, bifunctional core-shell magnetic fluorescent microspheres have been synthesized via a facile interface Pechini-type sol-gel method using citric acid and polyethylene glycol as chelating agent and cross-linking agent, respectively. The obtained Fe₃O₄@YVO₄:Eu³⁺ microspheres possess a typical core-shell structure, large magnetization, and strong fluorescence emission. The surface morphology and roughness of the microspheres can be flexibly tuned by controlling the multistep interface deposition process and subsequent calcination temperatures. Due to their well-integrated bifunctionalities, these magnetic fluorescent microspheres show outstanding performance in the visualization of latent fingerprints on various substrates with high definition and excellent anti-interference, and therefore they have great potential for application in identity recognition.

The untapped potential of magnetic nanoparticles for forensic investigations: A comprehensive review

With a growing interest in precise and sensitive diagnosis for criminal investigations, nanoparticles (NPs) have intrigued scientific minds working in the field of forensic science due to their exceptional properties. Magnetic nanoparticles (MNPs) have emerged as a powerful tool for improving forensic analysis due to their super magnetic behavior combined with smaller dimensions. MNP-based applications can benefit criminologists to solve criminal mysteries with greater precision and pace. This review highlights the different types of MNP-based applications and their developmental and implicational aspects of forensic science. It also renders insight into the future prospects of a splendid blend of nanotechnology and forensic science, leading to a better scientific analysis.

Red Fluorescent Carbon Dot Powder for Accurate Latent Fingerprint Identification using an Artificial Intelligence Program

Development and comparison of the latent fingerprints (LFPs) are two major studies in detection and identification of LFPs, respectively. However, integrated research studies on both fluorescent materials for LFP development and digital-processing programs for LFP comparison are scarcely seen in the literature. In this work, highly efficient red-emissive carbon dots (R-CDs) are synthesized in one pot and mixed with starch to form R-CDs/starch phosphors. Such phosphors are comparable with various substrates and suitable for the typical powder dusting method to develop LFPs. The fluorescence images of the developed LFPs are handled with an artificial intelligence program. For the optimal sample, this program presents an excellent matching score of 93%, indicating that the developed sample has very high similarity with the standard control. Our results are significantly better than the benchmark obtained by the traditional method, and thus, both the R-CDs/starch phosphors and the digital processing program fit well for the practical applications.

Individual Cloud-Based Fingerprint Operation Platform for Latent Fingerprint Identification Using Perovskite Nanocrystals as Eikonogen

Fingerprint formed through lifted papillary ridges is considered the best reference for personal identification. However, the currently available latent fingerprint (LFP) images often suffer from poor resolution, have a low degree of information, and require multifarious steps for identification. Herein, an individual Cloud-based fingerprint operation platform has been designed and fabricated to achieve high-definition LFPs analysis by using CsPbBr₃ perovskite nanocrystals (NCs) as eikonogen. Moreover, since CsPbBr₃ NCs have a special response to some fingerprint-associated amino acids, the proposed platform can be further used to detect metabolites on LFPs. Consequently, in virtue of Cloud computing and artificial intelligence (AI), this study has demonstrated a champion platform to realize the whole LFP identification analysis. In a double-blind simulative crime game, the enhanced LFP images can be easily obtained and used to lock the suspect accurately within one second on a smartphone, which can help investigators track the criminal clue and handle cases efficiently.

Drug-Abuse Nanotechnology: Opportunities and Challenges

Opioid drug abuse and dependence/addiction are complex disorders regulated by a wide range of interacting networks of genes and pathways that control a variety of phenotypes. Although the field has been extensively progressed since the birth of the National Institute on Drug Abuse in 1974, the fundamental knowledge and involved mechanisms that lead to drug dependence/addiction are poorly understood, and thus, there has been limited success in the prevention of drug addiction and development of therapeutics for definitive treatment and cure of addiction disease. The lack of success in both identification of addiction in at-risk populations and the development of efficient drugs has resulted in a serious social and economic burden from opioid drug abuse with global increasing rate of mortality from drug overdoses. This perspective aims to draw the attention of scientists to the potential role of nanotechnologies, which might pave the way for the development of more practical platforms for either drug development or identification and screening of patients who may be vulnerable to addiction after using opioid drugs.

Covalent Organic Polymers for Rapid Fluorescence Imaging of Latent Fingerprints

Rapid, simple and highly sensitive identification of latent fingerprints (LFPs) is an important issue related to national security and recognition of potential crimes. Here, we synthesize a series of covalent organic polymers (COPs) with colorful fluorescence (from blue to green, pale yellow, bright yellow, and red) and further investigate their performance for fluorescence imaging of LFPs. Results indicate that the COP materials can be used as fluorescence probes to rapidly visualize the precision substructure of LFPs within 5 s by simply spraying method, and tunable fluorescent color makes the COP probes have a high contrast and low interference for fluorescence imaging of LFPs on different substrates (including glass slides, paper, aluminum foil, plastic, ironware) in different backgrounds. We also further reveal the mechanism of COP probes for fluorescence imaging of LFPs. Importantly, the COP probes show high stability and could successfully achieve the fluorescence imaging for LFPs after aged for 45 days or washed by water. In short, this is the first report on the porous polymers for fluorescence imaging of LFPs and expected that it can be also applied to the fluorescence imaging of other fields.

Reversible Response of Luminescent Terbium(III)-Nanocellulose Hydrogels to Anions for Latent Fingerprint Detection and Encryption

Fingerprint fluorescence imaging has become one of the most prominent technologies in the field of forensic medicine, but it seldom considers the security protection of detection information, which is of great importance in modern society. Herein we demonstrate that luminescent Tb^III -carboxymethyl cellulose (CMC) complex binding aptamer hydrogels that are reversibly responsive to ClO^- /SCN^- can be used for the selective detection, protection, and storage of fingerprint information. The imaging information of the fingerprint can be quenched and recovered by ClO^- /SCN^- regulation, respectively, resulting in reversible on/off conversion of the luminescence signals for the encryption and decryption of multiple levels of information. The present study opens new avenues for multilevel imaging, data recording, and security protection of fingerprint information with tunable fluorescent hydrogels.

Development of Well-Preserved, Substrate-Versatile Latent Fingerprints by Aggregation-Induced Enhanced Emission-Active Conjugated Polyelectrolyte

The development of highly efficient latent fingerprint (LFP) technology remains extremely vital for forensic and criminal investigations. In this contribution, a straightforward, rapid, and cost-effective method has been established for the quick development of well-preserved latent fingerprint on multiple substrates, including plastic, glass, aluminum foil, metallic surfaces, and so forth, without any additional treatment, based on aggregation-induced enhanced emission-active conjugated polyelectrolyte (CPE) 3,3'-((2-(4-(1,2-diphenyl-2-(p-tolyl)vinyl)phenyl)-7-(7-methylbenzo[c][1,2,5]thiadiazol-4-yl)-9H-fluorene-9,9-diyl)bis(hexane-6,1-diyl))bis(1-methyl-1H-imidazol-3-ium) bromide, revealing clearly the third-level details (ridges, bifurcations, and pores) with high selectivity, high contrast, and no background interference even by blood stains, confirming the ability of the proposed technique for LFP detection with high resolution. The LFP development process was accomplished simply by immersing fingerprint-loaded substrate into the CPE solution for ∼1 min, followed by shaking off the residual polymer solution and then air drying. The CPE was readily transferred to the LFPs because of the strong electrostatic and hydrophobic interaction between the CPE molecules and the fingerprint components revealing distinct fluorescent images on various smooth nonporous surfaces.

Interfacial Separation-Enabled All-Dry Approach for Simultaneous Visualization, Transfer, and Enhanced Raman Analysis of Latent Fingerprints

It is of essential importance to visualize latent fingerprint (LFP) and analyze the compounds therein. For this purpose, various approaches have been developed but suffer from low imaging and/or detection efficiency. Most importantly, most of them require a necessary in-solution process and thus are not applicable to LFPs on bulky or water-sensitive substrates. In this work, we report an all-dry method to achieve simultaneous visualization and transfer of LFP and enhanced Raman analysis of multiple species therein. In this innovative approach, polydopamine (PDA) film-coated poly(dimethylsiloxane) (PDMS) flake with dense plasmonic silver nanoparticles (AgNPs@PDA@PDMS) was applied to cover the substrate carrying LFP. After gentle separation, the AgNPs@PDA film was transferred from PDMS to the LFP ridges to visualize a positive LFP pattern on the substrate, leaving behind a complementary (negative) LFP pattern on the PDMS flake. The compounds in the LFP were further analyzed via the AgNP-enhanced Raman technique. This approach enables high-contrast and full-feature visualization and transfer of LFP on arbitrary nonporous substrates and facilitates sensitive Raman analysis of multiple species in the sweat and thus promises great potential for practical applications.

Candle Soot Coating for Latent Fingermark Enhancement on Various Surfaces

We demonstrate a facile method termed candle soot coating (CSC) for fast developing latent fingermarks (LFMs) on various kinds of surfaces (glass, ceramic, metal, paper and adhesive tape). The CSC method can be considered as simple, fast, and low-cost as well as providing high contrast for LFM visualization in potential forensic applications.

Visualization of Sweat Fingerprints on Various Surfaces Using a Conjugated Polyelectrolyte

A conformation-variable conjugated polyelectrolyte responding to oppositely charged biomolecules was examined as an imaging agent for the detection of latent fingerprints (LFPs). Sulfonated poly(diphenylacetylene) (SPDPA) produces high-resolution fluorescence (FL) LFP images by simple wetting of the target objects with the polymer solution without any additional treatment. SPDPA readily interacts with LFP sweat components (especially amino acids) via electrostatic interactions, leading to significantly enhanced FL images in a "turn-on" mode. The FL emission enhancement was examined in a model reaction between SPDPA and an amino acid standard. Visualization with SPDPA is effective on various surfaces, including both rough (paper) and smooth (glass and plastic) ones. Moreover, SPDPA readily interacts with extremely thin sweat LFPs, especially on smooth glass surfaces.

High-Resolution and Universal Visualization of Latent Fingerprints Based on Aptamer-Functionalized Core-Shell Nanoparticles with Embedded SERS Reporters

Although fingerprints have been widely used in forensic investigations, low resolution and poor universality are still the main obstacles for the development of fingerprint visualization. In this paper, a facile and universal imaging protocol for latent fingerprints (LFPs) was developed by combining sandwiched SERS probes with the highly sensitive and selective recognition of aptamers. The embedded SERS probes (Au/pNTP/SiO2) successfully avoid the environment interference, ascertaining the stability and reproducibility of Raman signals, and simultaneously improve the efficiency of the fingerprint identification. This approach is operationally simple without complicated pre- or post-treatments. Moreover, the fingerprint images display the high resolution in which third-level details can be clearly identified. This is a general approach and can be used to detect various types of fingerprints, including sebaceous, eccrine, fresh LFPs, and aged LFPs on different substrates (such as smooth, scratching, semiporous, and porous surfaces).

The retrieval of fingerprint friction ridge detail from elephant ivory using reduced-scale magnetic and non-magnetic powdering materials

An evaluation of reduced-size particle powdering methods for the recovery of usable fingermark ridge detail from elephant ivory is presented herein for the first time as a practical and cost-effective tool in forensic analysis. Of two reduced-size powder material types tested, powders with particle sizes ≤ 40 μm offered better chances of recovering ridge detail from unpolished ivory in comparison to a conventional powder material. The quality of developed ridge detail of these powders was also assessed for comparison and automated search suitability. Powder materials and the enhanced ridge detail on ivory were analysed by scanning electron microscopy and energy dispersive X-ray spectroscopy and interactions between their constituents and the ivory discussed. The effect of ageing on the quality of ridge detail recovered showed that the best quality was obtained within 1 week. However, some ridge detail could still be developed up to 28 days after deposition. Cyanoacrylate and fluorescently-labelled cyanoacrylate fuming of ridge detail on ivory was explored and was less effective than reduced-scale powdering in general. This research contributes to the understanding and potential application of smaller scale powdering materials for the development of ridge detail on hard, semi-porous biological material typically seized in wildlife-related crimes.

Photoacoustic and Colorimetric Visualization of Latent Fingerprints

There is a high demand on a simple, rapid, accurate, user-friendly, cost-effective, and nondestructive universal method for latent fingerprint (LFP) detection. Herein, we describe a combination imaging strategy for LFP visualization with high resolution using poly(styrene-alt-maleic anhydride)-b-polystyrene (PSMA-b-PS) functionalized gold nanoparticles (GNPs). This general approach integrates the merits of both colorimetric imaging and photoacoustic imaging. In comparison with the previous methods, our strategy is single-step and does not require the signal amplification by silver staining. The PSMA-b-PS functionalized GNPs have good stability, tunable color, and high affinity for universal secretions (proteins/polypeptides/amino acids), which makes our approach general and flexible for visualizing LFPs on different substrates (presumably with different colors) and from different people. Moreover, the unique optical property of GNPs enables the photoacoustic imaging of GNPs-deposited LFPs with high resolution. This allows observation of level 3 hyperfine features of LFPs such as the pores and ridge contours by photoacoustic imaging. This technique can potentially be used to identify chemicals within LFP residues. We believe that this dual-modality imaging of LFPs will find widespread use in forensic investigations and medical diagnostics.

Covalent Patterning and Rapid Visualization of Latent Fingerprints with Photo-Cross-Linkable Semiconductor Polymer Dots

Fingerprint imaging and recognition represent the most important approach in personal identification. Here we designed and synthesized oxetane-functionalized semiconductor polymer dots (Ox-Pdots) for covalent patterning and rapid visualization of latent fingerprints. The high fluorescence brightness, large Stokes shift, and excellent surface properties of the Ox-Pdots lead to fingerprint imaging with high sensitivity and resolution. Fingerprint ridge structures with the first, second, and third levels of details were clearly developed within minutes. The method was facile and robust for visualization of fingerprints on various surfaces including glass, metal, and plastics. Moreover, the oxetane groups in the Ox-Pdots undergo cross-linking reactions induced by a short-time UV irradiation, yielding 3-D intermolecular polymer network. The resulting fingerprint patterns exhibit unparalleled stability against rigorous treatment, as compared to those by traditional Pdots. Our results demonstrate that the Ox-Pdots hold great promise for latent fingerprint imaging and fluorescence anticounterfeiting applications.

Dual-emitting quantum dot nanohybrid for imaging of latent fingerprints: simultaneous identification of individuals and traffic light-type visualization of TNT

A nanohybrid was employed for fingerprint imaging that was capable of simultaneous identification of individuals and TNT visualization in a “traffic-light” manner.

Fingerprints are a unique characteristic of an individual. Recently, it has been realized that fingerprints carry more information about individuals than just their identity, for example, they may identify potential addicts and terrorists carrying explosives. Therefore, the development of imaging moieties capable of both fingerprint staining and drug/explosive visualization is of significant importance for forensic chemistry. Here we developed a nanohybrid comprising green- and red-emitting QDs for simultaneous fingerprint imaging and TNT visualization in fingerprints. The red-emitting Cu-doped ZnCdS (Cu–ZnCdS) QDs were embedded into silica nanoparticles and the green-emitting ZnCdS QDs were anchored onto the surface of the silica nanoparticles and further functionalized with polyallylamine (PAA). Both components of the nanohybrid, i.e., the PAA-functionalized green QDs and red QD-doped silica nanoparticles, could be explored for fingerprint imaging. Due to the formation of a Meisenheimer complex between TNT and PAA, the green-emitting QDs could be quenched by TNT, meanwhile the red-emitting QDs were inert. Therefore, the nanohybrid exhibited a traffic light-type fluorescence color change (green-yellow-red) to TNT concentration in the range of 40–400 μM. This method is promising for potential applications in security-screening needs in public areas such as airports and train stations.

Surfactant chemistry for fluorescence imaging of latent fingerprints using conjugated polyelectrolyte nanoparticles

The polymer nanoparticles were readily transferred to the LFP to reveal highly distinguishable fluorescent images under the presence of surfactant with appropriate HLB value.

Immunological multimetal deposition for rapid visualization of sweat fingerprints

A simple method termed immunological multimetal deposition (iMMD) was developed for rapid visualization of sweat fingerprints with bare eyes, by combining the conventional MMD with the immunoassay technique. In this approach, antibody-conjugated gold nanoparticles (AuNPs) were used to specifically interact with the corresponding antigens in the fingerprint residue. The AuNPs serve as the nucleation sites for autometallographic deposition of silver particles from the silver staining solution, generating a dark ridge pattern for visual detection. Using fingerprints inked with human immunoglobulin G (hIgG), we obtained the optimal formulation of iMMD, which was then successfully applied to visualize sweat fingerprints through the detection of two secreted polypeptides, epidermal growth factor and lysozyme. In comparison with the conventional MMD, iMMD is faster and can provide additional information than just identification. Moreover, iMMD is facile and does not need expensive instruments.