Rapid screening methods reflecting the metabolic profile of urine are promising for assessing the risk of decreased renal function in children with obstructive uropathies. The aim of this pilot study was to evaluate the applicability of a reaction-based fingerprinting strategy for this purpose, which has previously demonstrated its effectiveness in recognizing samples with similar composition. The study included 27 children with hydronephrosis (HN, 5 patients) and vesicoureteral reflux (VUR, 15 patients), as well as healthy children without urinary pathology who comprised the control group (7 patients). Supervised chemometric analysis demonstrated that standard clinical and laboratory indicators enabled discrimination of urine samples from children with HN and VUR from the control group; however, the recognition accuracy was only satisfactory, ranging from 79% to 86%. Using the kinetic variant of fingerprinting, six indicator reactions of different natures involving dyes were investigated, with absorbance and fluorescence of the reaction products monitored photographically throughout the reaction. The introduction of urine samples into the indicator reactions enabled discrimination of both diagnoses (VUR and HN) from the control group and from each other, with recognition accuracy reaching 100%. Furthermore, no correlation was observed between the results obtained using kinetic-based methods and standard clinical and laboratory indicators, which may reflect different levels of the pathological process, namely functional and molecular. Thus, the reaction-based optical fingerprinting strategy can be considered a promising approach for in-depth non-invasive diagnostics in pediatric urology.

This study explores the potential of reaction-based optical fingerprinting and total X-ray fluorescence (TXRF) elemental analysis, both separately and in combination, as a rapid and inexpensive approach to preliminary cancer diagnostics. Plasma samples from BALB/c mice with transplanted mammary carcinoma (EMT-6) and BDF1 mice with Lewis lung carcinoma (LLC) or B16 melanoma were analyzed. The optical fingerprinting method relies on differences in the oxidation rate of a carbocyanine dye in the presence of blood plasma samples. Changes in fluorescence and absorption intensity were recorded photographically, enabling high-throughput analysis. The obtained images were digitized and the resulting dataset was processed using various statistical methods. Reaction-based optical fingerprinting achieved up to 100% observed accuracy in several classification tasks within the limited proof-of-concept dataset, distinguishing between healthy and diseased animals with transplanted tumors at different time points after tumor cell inoculation: 1 week for LLC, 2 weeks for B16, and 3 weeks for EMT-6. The same samples were simultaneously analyzed using TXRF, which also achieved 100% recognition accuracy when distinguishing between healthy animals and mice bearing LLC (after 1 and 2 weeks) or B16 melanoma (after 2 weeks). Although a direct combination of the reaction-based optical fingerprinting and TXRF analysis data into a single array did not consistently improve discrimination accuracy, the individual methods complement each other and enable effective screening of various cancer types. Overall, the kinetic based fingerprint method demonstrated significant potential in distinguishing between different types and stages of malignancies in mice.

Optical fingerprinting offers effective solutions to many practical problems that require distinguishing samples of similar composition. We are developing a kinetic version of optical fingerprinting based on conducting an indicator reaction in the presence of a sample and monitoring time-resolved optical changes during the reaction, which generates characteristic sample profiles that can be used for chemometric discrimination. This study investigates the influence of the choice of indicator reaction on the discrimination accuracy of various sample types, including irradiated foods (chicken breasts, potato tubers, and turkey liver), apple juices from different production years, natural waters, and model mixtures of pharmaceuticals. The method involved the oxidation of four heptamethine carbocyanine dyes by NaOCl or H2O2 in a 96-well plate with periodic absorption and emission measurements using a photographic method. The resulting kinetic profiles of the samples were processed using partial least squares - discriminant analysis (PLS-DA), linear discriminant analysis (LDA), and logistic/softmax regression. At least one indicator reaction provided high discrimination accuracy (above 90%) for each sample type, but no single reaction was universally optimal for all tasks. PLS-DA proved to be the most effective method for data processing for binary classifications. The kinetic-based methods were compared with alternative approaches, including intrinsic spectra, antioxidant assay (FRAP), and 3,3',5,5'-tetramethylbenzidine (TMB) oxidation, with all methods tested on the same samples.​ The method is versatile and cost-effective, requires simple setup and minimal sample preparation, and is sensitive to minor compositional changes.

Food irradiation is increasingly used to extend shelf life and control pests and diseases. Monitoring post-treatment doses typically relies on expensive, laborious instruments and may miss low doses. We previously proposed a chemical fingerprinting method that estimates dose based on indicator reaction rates, but this approach was tested only on freshly irradiated samples. In this study, we investigated the feasibility of determining the order of magnitude of dose in irradiated raw potato tubers after several days of storage. A completely randomized experimental design was used. Water extracts of potatoes were assayed in oxidation–reduction and aggregation reactions in 96-well plates; reaction rates were tracked by absorbance and fluorescence and analyzed chemometrically. We could distinguish dose orders of magnitude (0, 100, 1000 Gy) after 0, 2, and 6 days of storage at 4 °C. The accuracy of dose recognition on day 6 was at least 97% by using SoftMax regression (SR) or linear discriminant analysis (LDA); irradiated and non-irradiated samples were confidently distinguished using partial least square–discriminant analysis (PLS-DA). The reaction-based method of dose assessment is simple, rapid, and does not require sophisticated equipment.

Extensive monitoring of water sources necessitates the development of inexpensive and effective methods for monitoring their pollution. A particularly challenging task is detecting a sudden release of contaminated effluents into a water supply. To solve this issue, we employ a reaction-based fingerprinting technique that is based on conducting an indicator reaction of oxidation of carbocyanine dyes in the presence of a sample. The absorbance and fluorescence intensity are measured periodically using cameras, and the obtained data are processed using machine learning techniques. Monitoring of clean tap or river water was simulated by sampling every few days. Artificial contamination of this water was modeled by adding diluted sewage water (4 different samples). As a result, the contaminated samples were displayed as outliers in the score plots. In both tap and river water, 0.1% vol of wastewater (1000-fold dilution) was detected. The accuracy of discrimination between polluted and unpolluted samples exceeded 90% using linear discriminant analysis (LDA) or softmax regression (SR). Thereby, an unexpected discharge of wastewater into a water source could be rapidly detected with simple instruments. Development of this approach will contribute to improving the accuracy and ease of detection of water source contamination, making environmental monitoring methods more reliable for the benefit of public health.

Fluorescent conjugates of carbocyanine dyes with a ligand selective to prostate-specific membrane antigen were accessed by either peptide synthesis or CuAAC methodology, with the latter being more promising. The introduction of a propargylamino moiety at the meso-position of the polymethine chain of the fluorophores afforded the alkyne counterparts for the CuAAC reaction toward the ligand bearing azido group. The photochemical studies showed that the quantum yields of the obtained conjugates exceeded those for the unmodified fluorophores by more than 20 times.

Food irradiation is gaining popularity worldwide as a method for extending shelf life and controlling pests and diseases. Post-treatment irradiation doses are usually monitored using instrumental methods, which may be expensive, labor-intensive, time-consuming, and not allow for low-dose detection. We previously proposed a chemical fingerprinting strategy for estimating irradiation doses based on measuring the rate of an indicator reaction. However, the feasibility of dose assessment was demonstrated only for freshly irradiated samples. In this study, we investigated the feasibility of determining the order of magnitude of dose in irradiated raw potato tubers after several days of storage. The samples were extracted with water, and the extracts were introduced into oxidation-reduction and aggregation reactions carried out in a 96-well plate. The reaction rates were monitored by measuring absorbance and fluorescence of the reaction products, followed by chemo-metric processing. The feasibility to estimate doses to an order of magnitude (0, 100, 1000 Gy) was shown for storage time of 0, 2, and 6 days at 4°C. The accuracy of dose recognition on day 6 was at least 97% by using SoftMax regression (SR) or linear discriminant analysis (LDA). Irradiated and non-irradiated samples can be confidently distinguished using partial least square–discriminant analysis (PLS-DA). The reaction-based method of dose assessment is simple, rapid, and does not require sophisticated equipment.

Food irradiation on an industrial scale calls for the development of rapid and inexpensive methods for the dose estimation after irradiation. An emerging solution to this problem is a reaction-based optical sensing strategy that is based on monitoring dose-dependent indicator reactions. In this study, raw chicken breast samples from three producers were irradiated with 1 MeV accelerated electrons, extracted with water for 24 h, and introduced into reactions of carbocyanine dyes with H2O2 or hypochlorite. The absorbance and fluorescence of the reaction mixtures in different spectral ranges were measured photographically as a function of time. Supervised machine learning methods allowed to confidently discriminate between the samples irradiated with 250, 1000, and 5000 Gy and non-irradiated samples provided that the samples irradiated with known doses were from the same producers as the unknown ones. Dose estimation for samples from an unknown producer could be implemented by constructing a database using samples from a larger number of producers.

We report a modified carbocyanine-based asymmetric fluorescent dye, suitable for the azide-alkyne cycloaddition reaction, that possesses promising photochemical properties (Phi fl= 0,49). As an example of usage of the new fluorophore, it was conjugated to a ligand targeting prostate-specific membrane antigen (PSMA), one of the widely utilized prostate cancer markers.

For sensing small organic molecules, the tricarbocyanine derivatives are particularly efficient if contain at least two binding sites. As a step toward such ditopic structures, we synthesized the tricarbocyanines bearing ionogenic functional groups in the meso-position and studied their complexes with transition metals. New compounds exhibited a differential colorimetric response to individual pharmaceutical compounds tentatively due to the formation of mixed-ligand complexes.

Substitution reactions in carbocyanine dyes are used to determine nucleophilic compounds. The interaction of a chlorine-containing carbocyanine dye with a number of medicinal substances is studied. It is shown that, in the reaction with isoniazid in the presence of a surfactant, this dye selectively changes color from yellow-green to violet. The formation of a product of the substitution of chlorine for isoniazid is proven by chromatography–mass spectrometry. The reaction proceeds in 20 min in the presence of 1 mM cetyltrimethylammonium bromide. The limit of detection for isoniazid in water by the photometric method is 10 μg/mL and in diluted artificial urine using fluorimetry, 0.3 μg/mL. The procedure does not use full-spectrum equipment, which simplifies the determination.

Food irradiation is becoming increasingly popular in many countries for preserving and extending the shelf life of foods, which creates a demand for express methods for the detection of absorbed doses. This paper proposes an innovative method for the estimation of the dose absorbed by X-rayed beef samples using a reaction -based optical sensing technique that was proposed earlier by our team for the estimation of the dose absorbed by raw potatoes. Potato and beef samples were exposed to X-ray irradiation at 100 and 1000 Gy and then extracted by water at 23 C-degrees for 24 h or 60/70 C-degrees for 1 h. The resulting solutions were introduced to the reaction mixtures of dyes (carbocyanines, Rhodamines, or Crystal Violet) with oxidants (hypochlorite, bromate, or hydrogen peroxide). The fluorescence intensity and absorbance of the mixtures were periodically measured photographically using visualizers. The data were processed using linear discriminant analysis (LDA) and k -nearest neighbors algorithm (kNN). Using the most efficient individual reactions, the doses can be recognized with a 90-100% accuracy, and the combinations of up to 5 reactions can improve the accuracy to 100%. The protocol is simple and rapid: sample extraction time and indicator reactions take not more than 1 h each. The proposed method potentially has a wide area of applications ranging from plants to animal products.

Optical sensing is an inexpensive and simple technique in water pollution control that offers high sample throughput and field applications. In this work, we applied an innovative reaction-based optical fingerprinting strategy for the recognition of clean and synthetically contaminated waters. Samples of spring, well, borehole, pond, and tap water were introduced into the reaction mixtures containing carbocyanine dyes, the absorbance and fluorescence of which were monitored photographically at different times; the data were processed by linear discriminant analysis. Up to 11 clean water samples were completely discriminated; the samples artificially polluted with the soluble fraction of different brand engine oil [water-soluble fraction (WSF)] and iron(2+) supplied as Mohr's salt were discriminated from uncontaminated ones; the presence of 35-fold diluted WSF in water was also detected. Iron(2+) was detected in water samples at 3 mu g/L using the same indicator reactions. The proposed strategy can be useful in water pollution monitoring.

The work focuses on the development of a fluorimetric version of the fingerprint method based on conducting indicator reactions in the presence of a test sample. Observation of these reactions over time provides a more detailed information compared to batch methods, thereby improving sample recognition and enabling quantitative analysis. The proposed indicator reaction utilizes a commercial carbocyanine dye and 4-dimethylaminobenzaldehyde, whose interaction results in a decrease in fluorescence intensity and changes in absorbance over time. Three fluoroquinolones—moxifloxacin, levofloxacin, and ofloxacin—selectively change the signal in concentrations of 1 μM or higher, while other drugs, including different fluoroquinolones, do not interfere with the determination. Ofloxacin was detected in human urine samples at various times post-drug intake. A potential of using the same indicator reaction for sample recognition was demonstrated on examples of apple juices, soil extracts, and meat of varying freshness. Chemometric methods, including linear discriminant analysis, were used for data processing. The method achieved 97

For the purpose of imaging hydrophilic drugs, aggregates of gentamicin and vinorelbine with carbocyanine dyes fluorescing in the near-infrared region of the spectrum and a laurate ion as a counterion are obtained. To isolate the aggregates, precipitation from an aqueous solution of components is used. The size of the aggregates with gentamicin range from 200 to 600 nm; with vinorelbine, from 400 to 1000 nm; the surface ζ potential varies in the range of –15…–5 mV. The aggregates are sorbed by the subcutaneous fatty tissue, muscle, bone, and endothelial tissues of chickens. In the future, the resulting aggregates can be used to visualize drug delivery to the tissues of living organisms.

Water quality control employs techniques mostly targeting individual analytes; group detection is also practiced, but the choice of group methods is limited, which supports interest in developing such methods. We have examined the interaction of hypochlorite with a chlorine-containing heptamethine carbocyanine dye in the presence of 30 organic and inorganic model analytes that were found to induce diverse color changes in the system. The main supposed mechanisms are retardation of the dye oxidation with hypochlorite (presumably by scavenging chlorine radicals) and substitution of chlorine atom in the dye by the most nucleophilic analytes (amines, amino acids, proteins, DNA, phenol). The grass-green substitution product is more contrastingly visible against the dark-purple hypochlorite oxidation product of the dye than against the original emerald-green dye. The indicator reaction is monitored photographically for 10–40 min and the images are processed using principal component analysis (PCA) or linear discriminant analysis (LDA), allowing for data convolution for the complex color transitions. Nitrogen compounds are discriminated from the others, and more reactive analytes (tryptophan, cysteine, bovine serum albumin, and DNA) are detected in the presence of less reactive ones in natural water. The system is promising for the development of group assays for dissolved organic matter and the discrimination of water samples.

Optical sensor arrays are widely used in obtaining fingerprints of samples, allowing for solutions of recognition and identification problems. An approach to extending the functionality of the sensor arrays is using a kinetic factor by conducting indicator reactions that proceed at measurable rates. In this study, we propose a method for the discrimination of proteins based on their oxidation by sodium hypochlorite with the formation of the products, which, in turn, feature oxidation properties. As reducing agents to visualize these products, carbocyanine dyes IR-783 and Cy5.5-COOH are added to the reaction mixture at pH 5.3, and different spectral characteristics are registered every several minutes (absorbance in the visible region and fluorescence under excitation by UV (254 and 365 nm) and red light). The intensities of the photographic images of the 96-well plate are processed by principal component analysis (PCA) and linear discriminant analysis (LDA). Six model proteins (bovine and human serum albumins, γ-globulin, lysozyme, pepsin, and proteinase K) and 10 rennet samples (mixtures of chymosin and pepsin from different manufacturers) are recognized by the proposed method. The method is rapid and simple and uses only commercially available reagents.