Rapid Sample Analysis Research Articles

Rapid elimination of scattering in three-dimensional fluorescence spectra via deep learning

Three-dimensional fluorescence spectra are often affected by scattering effects, traditional scattering elimination methods rely excessively on parameter settings and cannot automatically eliminate scattering in batches, thereby limiting the application of fluorescence spectroscopy technology in rapid online monitoring and analysis of samples. In this study, we have developed a model based on a deep learning CycleGAN to rapidly eliminate scattering from three-dimensional fluorescence spectra. The proposed model efficiently eliminates scattering by simply inputting single or batches of contaminated fluorescent spectra. By training the CycleGAN using a large dataset of simulated three-dimensional fluorescence spectra and employing data augmentation, to the model can transform fluorescence spectra with scattering into ones without scattering. To validate the effectiveness of the proposed methed, we confirmed its generalization and reliability by eliminating scattering from two sets of previously unseen real experimental three-dimensional fluorescence spectra. We evaluated the effectiveness of scattering elimination across various noise levels and scattering widths, using metrics such as the mean absolute error, peak signal-to-noise ratio, structural similarity and cosine similarity. Furthermore, we conducted a component analysis using PARAFAC on the spectra post-scattering elimination, yielding correlation coefficients of >0.97 when compared to that in case of actual components. Finally, we compared the proposed model with traditional mathematical methods, such as blank subtraction and Delaunay triangulation. Results showed that the proposed model can automatically and efficiently eliminate scattering from fluorescence spectra in batches, substantially improving the efficiency of scattering elimination.

Performance Comparison of Ambient Ionization Techniques Using a Single Quadrupole Mass Spectrometer for the Analysis of Amino Acids, Drugs, and Explosives.

The utilization of ambient ionization (AI) techniques for mass spectrometry (MS) has significantly grown due to their ability to facilitate rapid and direct sample analysis with minimal sample preparation. This study investigates the performance of various AI techniques, including atmospheric solids analysis probe (ASAP), thermal desorption corona discharge (TDCD), direct analysis in real time (DART), and paper spray coupled to a Waters QDa mass spectrometer. The focus is on evaluating the linearity, repeatability, and limit of detection (LOD) of these techniques across a range of analytes, including amino acids, drugs, and explosives. The results show that each AI technique exhibits distinct advantages and limitations. ASAP and DART cover high concentration ranges, which may make them suitable for semiquantitative analysis. TDCD demonstrates exceptional linearity and repeatability for most analytes, while paper spray offers surprising LODs despite its complex setup (between 80 and 400 pg for most analytes). The comparison with electrospray ionization (ESI) as a standard method shows that ambient ionization techniques can achieve competitive LODs for various compounds such as PETN (80 pg ESI vs 100 pg ASAP), TNT (9 pg ESI vs 4 pg ASAP), and RDX (4 pg ESI vs 10 pg ASAP). This study underscores the importance of selecting the appropriate ambient ionization technique based on the specific analytical requirements. This comprehensive evaluation contributes valuable insights into the selection and optimization of AI techniques for diverse analytical applications.

Development of a triplex RT-qPCR assay for simultaneous quantification of Japanese encephalitis, Murray Valley encephalitis, and West Nile viruses for environmental surveillance.

The co-circulation of mosquito-borne Japanese encephalitis virus (JEV), Murray Valley encephalitis virus (MVEV), and West Nile virus (WNV) has impacted human and animal health in multiple countries worldwide. To facilitate early warnings and surveillance of the presence of these viral infectious agents in the environment, a triplex reverse transcription-quantitative PCR (RT-qPCR) was developed for simultaneous quantification of JEV, MVEV, and WNV in potential hotspots such as piggery and urban wastewater and environmental water samples. The performance of the developed triplex RT-qPCR assay was compared with that of simplex counterparts, all using the same primer and probe sequences. The quantifiable results showed a concordance rate of 93.9%-100% (Cohen's kappa) between the triplex and simplex assays. The mean concentrations of exogenous JEV, MVEV, and WNV using the triplex and simplex RT-qPCR assays were remarkably similar in piggery/urban wastewater and environmental water samples. However, the impacts of the matrix effects (i.e., sample composition and PCR inhibition) of environmental water samples on the accurate quantification of these viruses need to be considered. Taken together, this newly developed triplex RT-qPCR assay of JEV, MVEV, and WNV will allow for a more rapid and cost-efficient sample analysis and data interpretation. The application of the triplex assay for environmental surveillance may be a valuable tool to complement the existing disease and mosquito surveillance approaches used to safeguard the health of both humans and animals.IMPORTANCEThe co-circulation of mosquito-borne Japanese encephalitis virus (JEV), Murray Valley encephalitis virus (MVEV), and West Nile virus (WNV) poses significant threats to human and animal health globally. In this study, a triplex RT-qPCR assay was developed for simultaneous quantification of these viruses in wastewater and environmental water samples. Results demonstrated high concordance and sensitivity of the newly developed triplex RT-qPCR assay compared to simplex assays, indicating its efficacy for environmental surveillance. This cost-effective and rapid assay offers a vital tool for timely monitoring of mosquito-borne viruses in environmental samples, enhancing our ability to mitigate potential outbreaks and safeguard public health.

Low-cost heat assisted ambient ionization source for mass spectrometry in food and pharmaceutical screening.

Ambient Ionization Mass Spectrometry (AI-MS) techniques have revolutionized analytical chemistry by enabling rapid analysis of samples under atmospheric conditions with minimal to no preparation. In this study, the optimization of a cold atmospheric plasma for the analysis of food and pharmaceutical samples, liquid and solid, using a Heat-Assisted Dielectric Barrier Discharge Ionization (HA-DBDI) source is described. A significant enhancement in analyte signals was observed when a heating element was introduced into the design, potentially allowing for greater sensitivity. Furthermore, the synergy between the inlet temperature of the mass spectrometer and the heating element allows for precise control over the analytical process, leading to improved detection sensitivity and selectivity. Incorporating computational fluid dynamic (CFD) simulations into the study elucidated how heating modifications can influence gas transport properties, thereby facilitating enhanced analyte detection and increased signal intensity. These findings advance the understanding of HA-DBDI technology and provide valuable insights for optimizing AI-MS methodologies for a wide range of applications in food and pharmaceutical analysis.

Simultaneous spectrophotometric and chromatographic determination of Ketorolac and Dexamethasone: Overall assessment regarding environmental Impact, Practicality, and functionality principles

Determination of a drug combination that contains a minor component that is also a poorly UV absorbing analyte represents greet challenges in drug analysis. A fixed-dose ophthalmic combination of ketorolac tromethamine (KET) and dexamethasone sodium phosphate (DEX) (in the ratio of 5:1) is used to relieve post-surgical inflammation and seasonal allergic conjunctivitis due to their analgesic and anti-inflammatory activity. Five spectrophotometric methods and a reversed phase chromatographic separation method were developed and validated for simultaneous determination of both drugs in lab-prepared eye drops. Direct spectrophotometric determination of KET (the major, highly UV absorbing analyte) was achieved from the zero-order UV absorption spectra at 323 nm while DEX (which is the minor, poorly UV absorbing analyte) was quantified after applying several spectrophotometric methods. Either fundamental zero-order spectra or ratio spectra were used, and measurements were done at either single or dual wavelengths. The developed methods were: isosbestic point method, absorption factor method, dual wavelength method, ratio difference UV spectrophotometric method, and simultaneous equation method. The developed spectrophotometric methods determine KET in the linearity range of 2.0–12.0 μg/mL and DEX in the range of 5.0 – 35.0 μg/mL. For accurate spectrophotometric determination of DEX in the ratio of the dosage form, multiple standard addition method was applied. HPLC technique was also applied for separation and quantification of both drugs. Chromatographic separation was attained by using Hypersil ODS-C18 (150 x 4.6 mm, 5 μm) column. The mobile phase was composed of 50 % methanol: 50 % phosphate buffer (pH 2.5). The column compartment was maintained at 25 °C. Flow rate was adjusted at 1.2 mL/min and detection was performed by DAD at 254 nm. The linearity of HPLC method was 5.0–100.0 μg/mL, and 5.0–50.0 μg/mL for KET and DEX, respectively. Simultaneous determination of both drugs was applied to lab-prepared eye drops that contain also benzalkonium chloride as inactive ingredient. The developed methods determined the cited drugs with good and acceptable % recovery. The results of the developed methods and a reported HPLC method were compared using one-way ANOVA test, F-test and student’s t-test at confidence level 95 %, and they show no significant statistical difference. Assessment of greenness of the developed methods in comparison with reported HPLC method was performed using different tools, including analytical eco-scale, GAPI and AGREE. HPLC-EAT was also performed to ensure greenness of developed HPLC method. Moreover, assessment of practicality, applicability, and functionality of developed and reported methods was evaluated by BAGI metric tool and WAC calculator, respectively. The developed methods allow simple, rapid, and accurate analysis of quality control samples that contain KET and DEX.

Detection of powder samples based on UV Raman-fluorescence spectroscopy

Rapid and accurate analysis of powder samples is crucial for public safety and food security. Raman spectroscopy, noted for its many advantages, traditionally faces issues of low sensitivity and limited detection information when analyzing powder samples. This paper explores a detection method for powder samples using ultraviolet (UV) Raman-fluorescence spectroscopy. By leveraging the principles of Raman and fluorescence spectroscopy, a combined detection optical path was designed. Utilizing a 266 nm laser as the system light source, a UV Raman-fluorescence spectroscopy detection setup was constructed and seven representative powder samples were analyzed. The experimental results demonstrate that the setup effectively detects the Raman spectral features of inorganic powders like baking soda and extracts the fluorescence spectral features of organic powders such as 1,2,4,5-tetramethyltoluene. Additionally, it accurately analyzes the Raman and fluorescence spectral features of amino acids and glyphosate preparation powders. For complex powder samples with issues such as “substances with the same spectrum” and “complex and similar spectra”, UV Raman-fluorescence spectroscopy enhances spectral information dimensions, compensating for the limitations of traditional Raman spectroscopy. Furthermore, a convolutional neural network algorithm was employed to analyze the measured data of the seven powder samples increased the average recognition accuracy (AVG) from 62.53% to 98.41%. This improvement further validates the effectiveness of the proposed method in recognizing the properties of powder samples.

Near Infrared Aggregation Induced Electrogenerated Chemiluminescence Studies of Xanthene Dye

Electrogenerated chemiluminescence (ECL) serves as a versatile electrochemical-spectroscopic tool for rapid sample analysis, offering high sensitivity, good selectivity, and a low detection limit. During electrochemical redox reactions of luminophores and often ECL co-reactants, excited state luminophore species are formed through high energetic electron transfer between oxidized and reduced luminophore radicals or between the radical cation or anion and co-reactant intermediates. This process emits photons, generating ECL. Near infrared (NIR) luminophores represent an emerging class of materials in ECL studies. However, greater vibronic coupling between the ground and excited state in NIR luminophores with a lower band gap promotes nonradiative decay. The aggregation-induced emission (AIE) phenomenon overcomes these challenges, demonstrating enhanced radiative emission. We conducted a study on the photophysical, electrochemical, and ECL behavior of XanthCR-880 dye, which comprises a thienylpiperidine donor and a xanthene core as an acceptor. The central xanthene core provides extended conjugated length and increased charge transfer, resulting in NIR absorption at 880 nm and fluorescence emission at 960 nm, with a stroke shift of 80 nm. Cyclic voltammetry performed at a Pt electrode in MeCN with a scan rate of 50 mVs-1 revealed two oxidation waves and two reduction waves at 0.35 V, 0.70 V, -0.70 V, and -1.55 V vs Ag/Ag+, respectively. Due to the limited potential window of the Pt electrode in MeCN (not exceeding -2.5 V, a boron-doped diamond (BDD) electrode was employed at more negative potentials, uncovering an additional reduction wave at -2.62 V vs Ag/Ag+. The cathodic and anodic ECL behavior of XanthCR-880 dye was investigated using benzoyl peroxide and 2-(dibutylamino)ethanol as cathodic and anodic co-reactants, respectively. For cathodic ECL, XanthCR-880 dye produced two ECL waves at the BDD electrode, with peak potentials of -2.06 V and -2.36 V, respectively. In anodic ECL, relatively weak emission was observed at 1.05 V. ECL spectra were generated using the cathodic ECL pathway and interference filters as wavelength selectors, revealing a maximum emission at ~975 nm. The proposed ECL mechanism, as well as AIE studies, will also be discussed.

Mixed-mode cationic exchange paper combined with direct infusion mass spectrometry, a sustainable approach to determine opioids in biosamples

Direct infusion mass spectrometry (DI-MS/MS) allows the rapid analysis of samples and minimizes solvent usage by avoiding chromatographic separation. However, it is prone to ion suppression due to matrix effects, especially when biosamples are processed. In this context, sample preparation appears as the perfect complement to get proper analytical results. In this article, a novel and sustainable planar sorptive phase containing mixed-mode cationic exchange (MCX) particles is presented to overcome the limitations of DI-MS/MS in bioanalysis. The new phase uses cellulose paper as a natural substrate over which the particles can be retained using polyacrylonitrile (PAN) as the chemical binder. The high porosity of the cellulose substrate simplifies the synthesis since a straightforward dip-coating technique can be applied. For this purpose, MCX particles are initially dispersed in a PAN solution prepared in N,N-Dimethylformamide. A segment of paper is later introduced into the slurry, and the evaporation of the solvent leaves a film of PAN-MCX composite over the paper, where the particles are entrapped but accessible for the analyte's isolation. The resulting MCX-paper has been evaluated for the extraction of selected opioids (codeine, methadone, morphine, naloxone, oxycodone, and tramadol) from saliva and urine samples and their determination by direct infusion tandem mass spectrometry. Working at the optimized conditions, the limits of detection were in the low μg L−1 range. The precision, expressed as relative standard deviation, was better than 12 % under intra-day and inter-day conditions. The accuracy, expressed as relative recoveries, provides values in the ranges 89–113 % and 74–121% for saliva and urine, respectively. The method was finally applied to analyze saliva and urine samples collected from patients under codeine treatment.

Rapid analysis of untreated food samples by gel loading tip spray ionization mass spectrometry.

Rapid, efficient, versatile, easy-to-use, and non-expensive analytical approaches are globally demanded for food analysis. Many ambient ionization approaches based on electrospray ionization (ESI) have been developed recently for the rapid molecular characterization of food products. However, those approaches mainly suffer from insufficient signal duration for comprehensive chemical characterization by tandem MS analysis. Here, a commercially available disposable gel loading tip is used as a low-cost emitter for the direct ionization of untreated food samples. The most important advantages of our approach include high stability, and durability of the signal (> 10min), low cost (ca. 0.1 USD per run), low sample and solvent consumption, prevention of tip clogging and discharge, operational simplicity, and potential for automation. Quantitative analysis of sulfapyridine, HMF (hydroxymethylfurfural), and chloramphenicol in real sample shows the limit-of-detection 0.1μgmL-1, 0.005μgmL-1, 0.01μgmL-1; the linearity range 0.1-5μgmL-1, 0.005-0.25μgmL-1, 0.01-1μgmL-1; and the linear fits R2 ≥ 0.980, 0.991, 0.986. Moreover, we show that tip-ESI can also afford sequential molecular ionization of untreated viscous samples, which is difficult to achieve by conventional ESI. We conclude that tip-ESI-MS is a versatile analytical approach for the rapid chemical analysis of untreated food samples.

Pipette tip-electrospray mass spectrometry for determining opioids in urine, from on-site micro-handling to high-throughput centrifugal microextraction

Pipette tip-electrospray is a useful technique that synergically combines sample preparation and ambient ionization mass spectrometry for the rapid analysis of samples. In this work, the development of pipette tip extraction (PTE) is evaluated under two workflows that can be adapted to different analytical scenarios. Micro-handling PTE (MH-PTE) is an inherently portable technique that can be on-site applied. Centrifugal PTE (C-PTE), firstly presented here, allows a high sample throughput just requiring a benchtop centrifuge. The combination of both MH-PTE and C-PTE with pipette tip-electrospray is evaluated in this work for determining codeine and morphine, two metabolically related drugs, in urine and applied to the analysis of real samples. In the case of MH-PTE, intended to be on-site applied, the chemical stability of the analytes once extracted in the tips plays a crucial role. This stability has been studied in detail, simulating several transport/storage conditions compatible with regular postal services. The analytical features of both combinations are similar, although C-PTE provides a better sensitivity in terms of limit of detection (0.3 µg L−1 for codeine and 0.6 µg L−1 for morphine) compared to MH-PTE (0.6 µg L−1 for codeine and 1.5 µg L−1 for morphine). Moreover, the sample throughput provided by C-PTE is higher (up to 72 samples h−1) than that provided by MH-PTE (up to 12 samples h−1).

X-Ray fluorescence analysis of paraniobate based ceramics of composition Y<sub>3–x</sub>Yb<sub>x</sub>NbO<sub>7</sub>

A two-stage technique for X-ray fluorescence analysis of ceramic samples of composition Y3–xYbxNbO7 (where x = 0 – 3) has been developed. At the first stage, using the method of fundamental parameters (FPM), a rapid semi-quantitative analysis of ceramic samples and products of intermediate synthesis was carried out to determine their preliminary composition. At the second stage, the quantitative composition of the samples was determined using the constructed calibration dependencies. To construct calibration dependencies a series of reference samples containing 3.16 – 56.55% Y, 8.78 – 71.0% Yb, and 12.83 – 19.70% Nb was synthesized using a method similar to that used for preparation of the ceramic samples under study. Analytical lines of elements free from spectral overlaps and XRF conditions (current and voltage of an X-ray tube, exposure time, method of taking into account the background near the analytical line) were selected. The relative standard deviation of the results of Y, Yb, and Nb determination in ceramic samples did not exceed 0.66%, the relative error was no more than 1.63%. The results obtained were compared with the calculated content of analytes in the samples of stoichiometric composition and with the results of ICP-AES analysis of real ceramic samples. The developed technique provides determination of the main components of ceramic samples and can be used for analytical control of synthesis of rare earth paraniobates.

Advancements in Neurosurgical Intraoperative Histology.

Despite their relatively low incidence globally, central nervous system (CNS) tumors remain amongst the most lethal cancers, with only a few other malignancies surpassing them in 5-year mortality rates. Treatment decisions for brain tumors heavily rely on histopathological analysis, particularly intraoperatively, to guide surgical interventions and optimize patient outcomes. Frozen sectioning has emerged as a vital intraoperative technique, allowing for highly accurate, rapid analysis of tissue samples, although it poses challenges regarding interpretive errors and tissue distortion. Raman histology, based on Raman spectroscopy, has shown great promise in providing label-free, molecular information for accurate intraoperative diagnosis, aiding in tumor resection and the identification of neurodegenerative disease. Techniques including Stimulated Raman Scattering (SRS), Coherent Anti-Stokes Raman Scattering (CARS), Surface-Enhanced Raman Scattering (SERS), and Tip-Enhanced Raman Scattering (TERS) have profoundly enhanced the speed and resolution of Raman imaging. Similarly, Confocal Laser Endomicroscopy (CLE) allows for real-time imaging and the rapid intraoperative histologic evaluation of specimens. While CLE is primarily utilized in gastrointestinal procedures, its application in neurosurgery is promising, particularly in the context of gliomas and meningiomas. This review focuses on discussing the immense progress in intraoperative histology within neurosurgery and provides insight into the impact of these advancements on enhancing patient outcomes.

The former industrial site of the Angarsk Metallurgical Plant (Svirsk, Russia) 10 years later: current geochemical state and interannual change analysis based on Earth remote sensing data

The former industrial site of the Angarsk Metallurgical Plant (Svirsk, Russia) 10 years later: current geochemical state and interannual change analysis based on Earth remote sensing data

Modern machine-learning applications in ambient ionization mass spectrometry.

This article provides a comprehensive overview of the applications of methods of machine learning (ML) and artificial intelligence (AI) in ambient ionization mass spectrometry (AIMS). AIMS has emerged as a powerful analytical tool in recent years, allowing for rapid and sensitive analysis of various samples without the need for extensive sample preparation. The integration of ML/AI algorithms with AIMS has further expanded its capabilities, enabling enhanced data analysis. This review discusses ML/AI algorithms applicable to the AIMS data and highlights the key advancements and potential benefits of utilizing ML/AI in the field of mass spectrometry, with a focus on the AIMS community.

Spectral line confocal sensor signal analysis and correction: Unlocking reflectance difference sample measurements

Spectral line confocal imaging (LCI) technology enables high-resolution, rapid 3D surface morphology analysis of transparent materials and other samples, positioning it as a leading optical measurement tool. Nevertheless, where the sensor measures samples with significant variations in surface reflectance, the peak signals of the acquired images exhibit low signal-to-noise ratios or become distorted, hampering the peak extraction algorithm from accurately locating their peak positions. Consequently, it's arduous to reconstruct their precise surface topography. To enhance the sensor's dynamic measurement range and adaptability, this paper introduces an adaptive correction approach. It utilizes a regularized non-negative matrix to decompose images with various grey levels. This is followed by weighted frequency filtering and Gaussian enhancement of all the grey layers. Eventually, these layers are fused into one image with high contrast and uniformity. Using this approach, the sensor is capable of achieving precise 3D reconstruction with high-quality peak signals. Additionally, this study experimentally demonstrates the efficacy of the suggested approach by measuring the interdigital electrode and printed circuit boards (PCB). It should be noted that the technique presented in this paper is not limited to spectral line confocal instruments and is also effective for line laser and line structured light instruments.

Studying Venom Toxin Variation Using Accurate Masses from Liquid Chromatography–Mass Spectrometry Coupled with Bioinformatic Tools

This study provides a new methodology for the rapid analysis of numerous venom samples in an automated fashion. Here, we use LC-MS (Liquid Chromatography–Mass Spectrometry) for venom separation and toxin analysis at the accurate mass level combined with new in-house written bioinformatic scripts to obtain high-throughput results. This analytical methodology was validated using 31 venoms from all members of a monophyletic clade of Australian elapids: brown snakes (Pseudonaja spp.) and taipans (Oxyuranus spp.). In a previous study, we revealed extensive venom variation within this clade, but the data was manually processed and MS peaks were integrated into a time-consuming and labour-intensive approach. By comparing the manual approach to our new automated approach, we now present a faster and more efficient pipeline for analysing venom variation. Pooled venom separations with post-column toxin fractionations were performed for subsequent high-throughput venomics to obtain toxin IDs correlating to accurate masses for all fractionated toxins. This workflow adds another dimension to the field of venom analysis by providing opportunities to rapidly perform in-depth studies on venom variation. Our pipeline opens new possibilities for studying animal venoms as evolutionary model systems and investigating venom variation to aid in the development of better antivenoms.

The First Application of Laser-Induced Breakdown Spectroscopy: A Fast-Analytical Technique in Targeted Search for Elements in Geological Samples from Deep Boreholes in Latvia

Abstract Laser-induced breakdown spectroscopy (LIBS) provides a rapid, cost-effective, and extra-sensitive analysis of geological samples to make preliminary conclusions about the presence of valuable elements up to the trace levels in the ore. We present the first results of a highly sensitive qualitative analysis of the core samples of geological ore from two boreholes in Latvia (Staicele 1, from a depth range of 794–802 m, and Garsene (Subate) 2A, from a depth range of 1102–1103 m) using LIBS. Our measurements using this technique confirmed the high iron content and indicated traces of rare and high in-demand metals (such as Ti, V, Co, Sm, etc.) in the sample from Staicele, renewing interest in studying boreholes across Latvia. The presented pilot studies demonstrated effectiveness and unique possibility in performing a very sensitive and time-saving qualitative analysis of the composition of samples of ores from the old but still valuable borehole cores by using the LIBS method. We compare these measurements with other methods of sample analysis.

A Self-Powered Lactate Sensor Based on the Piezoelectric Effect for Assessing Tumor Development.

The build-up of lactate in solid tumors stands as a crucial and early occurrence in malignancy development, and the concentration of lactate in the tumor microenvironment may be a more sensitive indicator for analyzing primary tumors. In this study, we designed a self-powered lactate sensor for the rapid analysis of tumor samples, utilizing the coupling between the piezoelectric effect and enzymatic reaction. This lactate sensor is fabricated using a ZnO nanowire array modified with lactate oxidase (LOx). The sensing process does not require an external power source or batteries. The device can directly output electric signals containing lactate concentration information when subjected to external forces. The lactate concentration detection upper limit of the sensor is at least 27 mM, with a limit of detection (LOD) of approximately 1.3 mM and a response time of around 10 s. This study innovatively applied self-powered technology to the in situ detection of the tumor microenvironment and used the results to estimate the growth period of the primary tumor. The availability of this application has been confirmed through biological experiments. Furthermore, the sensor data generated by the device offer valuable insights for evaluating the likelihood of remote tumor metastasis. This study may expand the research scope of self-powered technology in the field of medical diagnosis and offer a novel perspective on cancer diagnosis.

A novel fluorescent sensor for selective rifampicin detection based on the bio-inspired molecularly imprinted polymer-AgInS2/ZnS quantum dots.

A fluorescent sensing material based on the ternary core-shell quantum dots with outstanding optical properties and a bio-inspired molecularly imprinted polymer (MIP) as a recognition element has been prepared for selective detection of rifampicin (RFP). Firstly, AgInS2/ZnS core/shell quantum dots (ZAIS QDs) were prepared by a hydrothermal process. Then, the fluorescent sensor was prepared by coating these QDs by a dopamine-based MIP layer. The fluorescence of MIP@ZAIS QDs was quenched by RFP probably due to the photoinduced electron transfer process. The quenching constant was much higher for MIP@ZAIS QDs than the non-imprinted polymer@QDs, indicating that MIP@ZAIS QDs could selectively recognize RFP. Under the optimized conditions, the sensor had a good linear relationship at the RFP concentration range of 5.0 to 300nM and the limit of detection was 1.25nM. The respond time of the MIP@ZAIS QDs was 5min, and the imprinting factor was 6.3. It also showed good recoveries ranging from 98 to 101%, for analysis of human plasma samples. The method is simple and effective for the detection of RFP and offers a practical application for the rapid analysis of human plasma samples.

DNA nanoflowers encapsulating horseradish peroxidase as a signal amplification tag for rapid diagnosis in cytology specimens

Rapid analysis of cytology samples obtained by minimally invasive sampling is essential in clinical diagnosis, yet existing diagnostic methods are often cumbersome and time-consuming. To rapidly detect the scanty number of cells in specimens, a multifunctional detection probe based on DNA nanoflower structure was prepared in this study, which possesses both signal output capability of fluorescence and oxidation reaction (colorimetric assay) for ultra-sensitive cancer cell detection. Firstly, DNA nanoflowers encapsulating horseradish peroxidase (HRP-DNA Nanoflowers, HDFs) were prepared by the rolling circle amplification (RCA) reaction and then hybridized with the aptamers labeled with fluorophores to construct the multivalent aptamer HDFs (Multi-Aptamer-HDFs) with fluorescence effect and efficient cancer cell targeting. The Multi-Aptamer-HDFs probe can be used to detect fresh clinical cytology specimens directly for fluorescence observation with sensitivity and specificity of 88.64%, and 84.85%, respectively. In addition, Multi-Aptamer-HDFs has peroxidase activity due to the encapsulation of HRP, which can catalyze the oxidation of substrates such as ABTS and DAB for color development. Therefore, we applied Multi-Aptamer-HDFs to one-step staining of clinical cytology cell blocks with a sensitivity of 88.41% and a specificity of 83.33%, which required fewer steps and reagents with a significantly shorter time required for immunocytochemical staining. The multifunctional probe, Multi-Aptamer-HDFs, prepared in this study is expected to be better applied in the rapid cellular analyses and one-step immunostaining, which is expected to provide a new means for rapid on-site assessment and on-site preliminary diagnosis.