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Keywords = colorimetric pH measurement

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13 pages, 1537 KiB  
Article
Correlation of SERPINA-1 Gene Over-Expression with Inhibition of Cell Proliferation and Modulation of the Expression of IL-6, Furin, and NSD2 Genes
by Nassim Tassou, Hajar Anibat, Ahmed Tissent and Norddine Habti
Biologics 2025, 5(3), 22; https://doi.org/10.3390/biologics5030022 - 6 Aug 2025
Abstract
Background and Objectives: The cytokine IL-6, methyltransferase NSD2, pro-protein convertase Furin, and growth factor receptor IGF-1R are essential factors in the proliferation of cancer cells. These proteins are involved in the tumor process by generating several cell-signaling pathways. However, the interactions of these [...] Read more.
Background and Objectives: The cytokine IL-6, methyltransferase NSD2, pro-protein convertase Furin, and growth factor receptor IGF-1R are essential factors in the proliferation of cancer cells. These proteins are involved in the tumor process by generating several cell-signaling pathways. However, the interactions of these oncogenic biomarkers, Furin, IL-6, and NSD2, and their links with the inhibitor SERPINA-1 remain largely unknown. Materials and Methods: Cell proliferation is measured by colorimetric and enzymatic methods. The genetic expressions of SERPINA-1, Furin, IL-6, and NSD2 are measured by qRT-PCR, while the expression of IGF-1R on the cell surface is measured by flow cytometry. Results: The proliferation of cells overexpressing SERPINA-1 (JP7pSer+) is decreased by more than 90% compared to control cells (JP7pSer-). The kinetics of the gene expression ratios of Furin, IL-6, and NSD2 show an increase for 48 h, followed by a decrease after 72 h for the three biomarkers in JP7pSer+ cells compared to JP7pSer- cells. The expression of IGF-1R on the cell surface in both cell lines is low, with JP7pSer- cells expressing 1.33 times more IGF-1R than JP7pSer+ cells. Conclusions: These results suggest gene correlations of SERPINA-1 overexpression with decreased cell proliferation and modulation of gene expression of Furin, IL-6, and NSD2. This study should be complemented by molecular transcriptomic and proteomic experiments to better understand the interaction of SERPINA-1 with IL-6, Furin, and NSD2, and their effect on tumor progression. Full article
(This article belongs to the Topic Advances in Anti-Cancer Drugs: 2nd Edition)
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19 pages, 8805 KiB  
Article
Effects of Inactive Yeast Biostimulants on Mechanical and Color Attributes of Wine Grape Cultivars
by Giovanni Gentilesco, Vittorio Alba, Giovanna Forte, Rosa Anna Milella, Giuseppe Roselli and Mauro Eugenio Maria D’Arcangelo
Sustainability 2025, 17(15), 6958; https://doi.org/10.3390/su17156958 - 31 Jul 2025
Viewed by 159
Abstract
Background: Biostimulants naturally improve plant growth, stress tolerance, and nutrient use efficiency and activate defenses by increasing protective metabolites (phenols, anthocyanins) in grapes. In viticulture, especially when using inactive yeasts, they modulate genetic expression and improve the skin resistance, color, and aroma profile [...] Read more.
Background: Biostimulants naturally improve plant growth, stress tolerance, and nutrient use efficiency and activate defenses by increasing protective metabolites (phenols, anthocyanins) in grapes. In viticulture, especially when using inactive yeasts, they modulate genetic expression and improve the skin resistance, color, and aroma profile of wine grapes in line with sustainable practices. Methods: Two wine grape cultivars, Merlot and Cabernet Sauvignon, were sprayed with the inactive yeast Saccharomyces cerevisiae in a single treatment in pre-veraison or in a double treatment in pre-veraison and veraison. Berry weight, must, total polyphenols, anthocyanins, and mechanical and colorimetric properties were measured on fresh grapes. Results: Two-way ANOVA revealed that titratable acidity (TA), pH, and total polyphenol content (TPC) were not affected, while mean berry weight and anthocyanin content varied by cultivar, treatment, and interaction; total soluble solids (TSS) differed only by cultivar. Inactive yeasts reduced weight in the single-treatment thesis but stabilized it in the double-treatment one; anthocyanins decreased in Cabernet Sauvignon but increased in Merlot. Mechanical and colorimetric analyses showed cultivar-dependent responses, with significant improvements in elasticity, skin thickness, and hue of berries, especially in Merlot when the treatment was applied twice. Conclusions: Inactive yeasts (IYs) showed an effect on the weight of the berries, the anthocyanins, the mechanics, and the color; Merlot significantly improved skin thickness, elasticity, and hue; and Cabernet remained less reactive to treatments. Full article
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13 pages, 11974 KiB  
Article
A Study and Comparative Analysis of the Action of the Deacidifying Products Bookkeeper® and Nanorestore Paper® on Plant Textile Fibres
by A. Nani, C. Ricci, A. Gatti and A. Agostino
Heritage 2025, 8(7), 287; https://doi.org/10.3390/heritage8070287 - 19 Jul 2025
Viewed by 357
Abstract
The aim of this study is to evaluate the effectiveness of deacidifying treatments for the restoration of textiles used as supports for works of art, with particular attention to the chemical stability, colour variation and mechanical resistance of the materials over time. The [...] Read more.
The aim of this study is to evaluate the effectiveness of deacidifying treatments for the restoration of textiles used as supports for works of art, with particular attention to the chemical stability, colour variation and mechanical resistance of the materials over time. The present study involved the analysis of two products: BookkeeperTM, containing magnesium oxide, and NanorestoreTM, a dispersion of calcium hydroxide in alcoholic solutions of ethanol and 2-propanol. The products were applied to a series of tests on cotton, linen and jute fabrics. The experimental approach comprised an artificial degradation process of the fabrics, followed by the application of the treatments and an accelerated ageing cycle. A series of parameters were monitored throughout the experiment, encompassing surface pH, chromatic shifts ascertained through colorimetric measurements and the morphological transformations of the fabrics, as elucidated by scanning electron microscopy (SEM-EDS). The findings yielded from this study have enabled the delineation of the behaviour exhibited by the treated materials over an extended timeframe. This underscores the significance of a judicious selection of treatments, contingent upon the particular chemical and physical attributes inherent to the fabrics in question. Full article
(This article belongs to the Section Materials and Heritage)
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29 pages, 18412 KiB  
Article
Freeze-Drying as a Stabilization Strategy for Natural Dyes Derived from Lawsonia inermis L. and Indigofera suffruticosa
by Valvanuz Cahuantzi, Rosalba Patiño Herrera, Norma Verónica Zavala Alonso, Daniela Salado Leza, María Selene Berber Mendoza and Elías Pérez
Analytica 2025, 6(3), 22; https://doi.org/10.3390/analytica6030022 - 9 Jul 2025
Viewed by 484
Abstract
This study focuses on the stabilization of a natural hair dye derived from Lawsonia inermis L. (henna) and Indigofera suffruticosa (indigo). Although various formulations already exist, they are designed for immediate use and cannot be stored. Lawsonia, a primary component of the [...] Read more.
This study focuses on the stabilization of a natural hair dye derived from Lawsonia inermis L. (henna) and Indigofera suffruticosa (indigo). Although various formulations already exist, they are designed for immediate use and cannot be stored. Lawsonia, a primary component of the dye, tends to degrade after release. To ensure its stability, freeze-drying was implemented as a protective measure. Colorimetric analysis confirmed the dye’s ability to maintain an intense, uniform coloration even after multiple washing cycles. Stability tests demonstrate that freeze-drying effectively enhances the dye’s stability and capacity to retain its physical properties and color under various environmental conditions, demonstrating its potential for long-term use. The dye’s pH (5.05) aligns with the natural pH of hair, promoting cuticle sealing and improving hair health. Cytotoxicity tests confirmed the dye’s safety, showing no harmful effects. Gray hair exhibited a total color difference (ΔE) of 64.06 after the initial application, using natural gray hair as a reference. By the third application, ΔE increased to 69.86 and gradually decreased to 68.20 after 15 washing cycles, highlighting its long-term durability. Gray hair exposed to 720 h of UV radiation showed a ΔE of 17.34, whereas dyed gray hair exhibited a ΔE of 2.96 compared to non-UV-exposed samples. This indicates superior resistance to color degradation in dyed hair. Also, SEM imaging revealed the dye’s restorative effects, progressively improving hair cuticle structure with each application. Full article
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11 pages, 928 KiB  
Article
Impact of Different Regimens of Fluoridated Dentifrice Application on the pH and Inorganic Composition in an Oral Microcosm Biofilm Model
by Patrícia de Lourdes Budoia de Carvalho, Juliano Pelim Pessan, Bruna do Amaral, Amanda Costa Troncha, Samuel Campos Sousa, Douglas Roberto Monteiro, Thayse Yumi Hosida, Alberto Carlos Botazzo Delbem and Caio Sampaio
Microorganisms 2025, 13(7), 1612; https://doi.org/10.3390/microorganisms13071612 - 9 Jul 2025
Viewed by 327
Abstract
This study evaluated the pH, fluoride (F), and calcium (Ca) concentrations in saliva-derived microcosm biofilms following treatments with dentifrices applied at different amounts and F concentration. Human saliva was inoculated into McBain culture medium, and treatments were applied at 72/78/96 h (1 min). [...] Read more.
This study evaluated the pH, fluoride (F), and calcium (Ca) concentrations in saliva-derived microcosm biofilms following treatments with dentifrices applied at different amounts and F concentration. Human saliva was inoculated into McBain culture medium, and treatments were applied at 72/78/96 h (1 min). Fluoridated dentifrices containing 550 or 1100 ppm F (550F and 1100F, respectively) were used at the following combinations (intensities): (i-1) 550F/0.08 g or 1100F/0.04 g; (i-2) 550F/0.16 g or 1100F/0.08 g; (i-3) 550F/0.32 g or 1100F/0.16 g. A negative control (fluoride-free dentifrice—PLA) was also included. Biofilm F and Ca were measured with an ion-selective electrode and colorimetrically, respectively, while pH in the culture medium was measured with a pH electrode. Data were subjected to ANOVA and Student–Newman–Keuls’ test (p < 0.05). F-dentifrices did not significantly alter pH compared to PLA, except for 1100F at i-3. Biofilm F levels at i-1 and i-2 were comparable, for both 550F and 1100F, while 1100F at i-3 led to the highest biofilm F concentration. All F-groups showed significantly higher Ca levels than PLA, especially at i-2 and i-3. In conclusion, the interplay between dentifrice amount and F concentration was more influential on the biofilm’s inorganic composition and pH than either variable alone. Full article
(This article belongs to the Section Biofilm)
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24 pages, 4028 KiB  
Article
Therapeutic Potential of Clerodendrum glabrum and Gardenia volkensii Acetone Extracts: Antioxidant, Antibacterial, and Anti-Virulence Activities
by Ndzalama Sithole, Mashilo Mash Matotoka and Peter Masoko
Microbiol. Res. 2025, 16(6), 129; https://doi.org/10.3390/microbiolres16060129 - 16 Jun 2025
Viewed by 501
Abstract
Background/Objectives: Antibiotic-resistant bacteria pose a global health threat, driving the need for alternative treatments. Medicinal plants such as Clerodendrum glabrum and Gardenia volkensii are promising sources of bioactive compounds. This study evaluated the antioxidant, antibacterial, and anti-virulence activities of their acetone extracts, comparing [...] Read more.
Background/Objectives: Antibiotic-resistant bacteria pose a global health threat, driving the need for alternative treatments. Medicinal plants such as Clerodendrum glabrum and Gardenia volkensii are promising sources of bioactive compounds. This study evaluated the antioxidant, antibacterial, and anti-virulence activities of their acetone extracts, comparing sonication and conventional shaking extraction methods. Methods: Colorimetric methods assessed total polyphenol content. Antioxidant activity was measured using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and hydrogen peroxide (H2O2) assays. Antibacterial effects against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes were analysed through broth microdilution, total activity, growth kinetics, and combinational studies. Anti-virulence activity was assessed via biofilm biomass inhibition, metabolic activity and anti-swarming assays. Results: Phenolics were the most abundant phytochemicals, followed by flavonols. C. glabrum exhibited strong antioxidant activity in both DPPH and H2O2 assays. MIC values ranged from 0.16 to 2.5 mg/mL, with the shaken G. volkensii leaf extract showing the highest total activity (575 mL/g) against E. coli. A combination of G. volkensii leaf extract and gentamicin resulted in an additive antibacterial effect. All extracts prevented the formation of biofilm biomass in all tested microorganisms (inhibition > 50%) except for extracts obtained by sonication. The sonicated leaf extract of C. glabrum inhibited initial E. coli attachment. Additionally, the sonicated leaf extract of C. glabrum inhibited P. aeruginosa motility. Conclusions: These findings suggested that a targeted approach based on plant species and extraction methods could improve treatment outcomes against biofilm-associated pathogens. Notably, acetone extracts derived from C. glabrum and G. volkensii exhibit considerable potential as natural sources of antioxidant, antibacterial, and anti-virulence agents effective against nosocomial infections. Full article
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13 pages, 3061 KiB  
Article
Color Variation in 3D-Printed Orthodontic Aligners as a Compliance Indicator: A Prospective Pilot Study
by Francesca Cremonini, Giuseppe Chiusolo, Filippo Pepe and Luca Lombardo
Appl. Sci. 2025, 15(12), 6409; https://doi.org/10.3390/app15126409 - 6 Jun 2025
Viewed by 428
Abstract
Patient compliance remains a significant challenge in orthodontic treatment with clear aligners, as adherence to prescribed wear time is often suboptimal. This study investigated the potential of colorimetric analysis as a method to assess compliance with NOXI 3D-printed night-time aligners. Specifically, it evaluated [...] Read more.
Patient compliance remains a significant challenge in orthodontic treatment with clear aligners, as adherence to prescribed wear time is often suboptimal. This study investigated the potential of colorimetric analysis as a method to assess compliance with NOXI 3D-printed night-time aligners. Specifically, it evaluated color variations in polyamide aligners due to thermo-oxidation, using the RGB (Red, Green, Blue) color model as a non-invasive indicator. In total, 10 patients participated in this prospective study, wearing aligners for either 7 or 12 h daily over a 14-day period. Colorimetric measurements were collected via a smartphone-based application, and statistical analyses examined correlations between wear duration and color changes. The results revealed a significant association between a longer wear time and increased discoloration (p < 0.001), supporting the feasibility of RGB-based monitoring as a reliable compliance tool. However, individual variability in saliva composition, diet, and oral hygiene may have influenced the results, highlighting the need for further research into potential confounding variables. These findings underscore the promise of integrating digital monitoring technologies to improve adherence tracking and patient management in orthodontics. Future studies should refine the methodology and validate its efficacy in larger, more diverse populations. Full article
(This article belongs to the Special Issue Orthodontics: Advanced Techniques, Methods and Materials)
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21 pages, 1433 KiB  
Article
Evaluation of RT-LAMP for SARS-CoV-2 Detection in Animal Feces
by Aimee Pepper, Sandipty Kayastha, Megan Miller, Jake Guag, Andriy Tkachenko, Matthew Allender, Karen Terio and Leyi Wang
Viruses 2025, 17(6), 783; https://doi.org/10.3390/v17060783 - 29 May 2025
Viewed by 517
Abstract
The wide host range, potential lethality, and zoonotic potential of SARS-CoV-2 infection in animals highlights the need for additional surveillance strategies. We validated a commercial, pH-based, colorimetric RT-LAMP assay for the detection of SARS-CoV-2 RNA in animal feces. The comparator assay was rRT-PCR. [...] Read more.
The wide host range, potential lethality, and zoonotic potential of SARS-CoV-2 infection in animals highlights the need for additional surveillance strategies. We validated a commercial, pH-based, colorimetric RT-LAMP assay for the detection of SARS-CoV-2 RNA in animal feces. The comparator assay was rRT-PCR. The limit of detection of the RT-LAMP assay was 72 genome copies per reaction. RT-LAMP was highly specific for SARS-CoV-2 and did not detect other human or animal coronaviruses. RT-LAMP was robust, with valid results generated for incubation lengths of 30 to 45 min, incubation temperatures of 60 to 70 °C, and reaction volumes of 10 to 25 µL. The diagnostic sensitivity was 100% for clinical fecal samples with high viral loads (Ct ≤ 25), 97.4% for samples with moderate to high viral loads (Ct ≤ 33), and 62% overall (Ct ≤ 40). The diagnostic specificity was 97.9%. Blinded method testing organized by an independent laboratory confirmed the satisfactory reproducibility of the assay. To our knowledge, this study represents the first validation of RT-LAMP for SARS-CoV-2 detection in animals. RT-LAMP testing could detect SARS-CoV-2 infection more rapidly and at the point of care in animals with moderate to high viral loads, allowing for earlier implementation of control measures. Full article
(This article belongs to the Section Animal Viruses)
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25 pages, 9203 KiB  
Article
Screening, Identification, and Fermentation of Brevibacillus laterosporus YS-13 and Its Impact on Spring Wheat Growth
by Wenjing Zhang, Xingxin Sun, Zele Wang, Jiayao Li, Yuanzhe Zhang, Wei Zhang, Jun Zhang, Xianghan Cheng and Peng Song
Microorganisms 2025, 13(6), 1244; https://doi.org/10.3390/microorganisms13061244 - 28 May 2025
Viewed by 436
Abstract
The low availability of phosphorus (P) in soil has become a critical factor limiting crop growth and agricultural productivity. This study aimed to isolate and evaluate a bacterial strain with high phosphate-solubilizing capacity to improve soil phosphorus utilization and promote crop growth. A [...] Read more.
The low availability of phosphorus (P) in soil has become a critical factor limiting crop growth and agricultural productivity. This study aimed to isolate and evaluate a bacterial strain with high phosphate-solubilizing capacity to improve soil phosphorus utilization and promote crop growth. A phosphate-solubilizing bacterium, designated as YS-13, was isolated from farmland soil in Henan Province, China, and identified as Brevibacillus laterosporus based on morphological characteristics, physiological and biochemical traits, and 16S rDNA sequence analysis. Qualitative assessment using plate assays showed that strain YS-13 formed a prominent phosphate solubilization zone on organic and inorganic phosphorus media containing lecithin and calcium phosphate, with D/d ratios of 2.28 and 1.57, respectively. Quantitative evaluation using the molybdenum–antimony colorimetric method revealed soluble phosphorus concentrations of 21.24, 6.67, 11.73, and 17.05 mg·L−1 when lecithin, ferric phosphate, calcium phosphate, and calcium phytate were used as phosphorus sources, respectively. The fermentation conditions for YS-13 were optimized through single-factor experiments combined with response surface methodology, using viable cell count as the response variable. The optimal conditions were determined as 34 °C, 8% inoculum volume, initial pH of 7.55, 48 h incubation, 5 g L−1 NaCl, 8.96 g L−1 glucose, and 8.86 g L−1 peptone, under which the viable cell count reached 6.29 × 108 CFU mL−1, consistent with the predicted value (98.33%, p < 0.05). The plant growth-promoting effect of YS-13 was further validated through a pot experiment using Triticum aestivum cv. Jinchun 6. Growth parameters, including plant height, fresh biomass, root length, root surface area, root volume, and phosphorus content in roots and stems, were measured. The results demonstrated that YS-13 significantly enhanced wheat growth, with a positive correlation between bacterial concentration and growth indicators, although the growth-promoting effect plateaued at higher concentrations. This study successfully identified a high-efficiency phosphate-solubilizing strain, YS-13, and established optimal culture conditions and bioassay validation, laying a foundation for its potential application as a microbial inoculant and providing theoretical and technical support for reducing phosphorus fertilizer inputs and advancing sustainable agriculture. Full article
(This article belongs to the Section Plant Microbe Interactions)
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16 pages, 6282 KiB  
Article
Color QR Codes for Smartphone-Based Analysis of Free Chlorine in Drinking Water
by María González-Gómez, Ismael Benito-Altamirano, Hanna Lizarzaburu-Aguilar, David Martínez-Carpena, Joan Daniel Prades and Cristian Fàbrega
Sensors 2025, 25(11), 3251; https://doi.org/10.3390/s25113251 - 22 May 2025
Viewed by 723
Abstract
Free chlorine (FC) plays a crucial role in ensuring the safety of drinking water by effectively inactivating pathogenic microorganisms. However, traditional methods for measuring FC levels often require specialized equipment and laboratory settings, limiting their accessibility and practicality for on-site or point-of-use monitoring. [...] Read more.
Free chlorine (FC) plays a crucial role in ensuring the safety of drinking water by effectively inactivating pathogenic microorganisms. However, traditional methods for measuring FC levels often require specialized equipment and laboratory settings, limiting their accessibility and practicality for on-site or point-of-use monitoring. QR Codes are powerful machine-readable patterns that are used worldwide to encode information (i.e., URLs or IDs), but their computer vision features allow QR Codes to act as carriers of other features for several applications. Often, this capability is used for aesthetics, e.g., embedding a logo in the QR Code. In this work, we propose using our technique to build back-compatible Color QR Codes, which can embed dozens of colorimetric references, to assist in the color correction to readout sensors. Specifically, we target two well-known products in the HORECA (hotel/restaurant/café) sector that qualitatively measure chlorine levels in samples of water. The two targeted methods were a BTB strip and a DPD powder. First, the BTB strip was a pH-based indicator distributed by Sensafe®, which uses the well-known bromothymol blue as a base-reactive indicator; second, the DPD powder was a colorimetric test distributed by Hach®, which employs diethyl-p-phenylenediamine (DPD) to produce a pink coloration in the presence of free chlorine. Custom Color QR Codes were created for both color palettes and exposed to several illumination conditions, captured with three different mobile devices and tested over different water samples. Results indicate that both methods could be correctly digitized in real-world conditions with our technology, rendering a 88.10% accuracy for the BTB strip measurement, and 84.62% for the DPD powder one. Full article
(This article belongs to the Special Issue Colorimetric Sensors: Methods and Applications (2nd Edition))
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18 pages, 5945 KiB  
Article
Investigation of Polymers as Matrix Materials for Application in Colorimetric Gas Sensors for the Detection of Ammonia
by Sonja Hoffmann, Michael Henfling and Sabine Trupp
Sensors 2025, 25(9), 2829; https://doi.org/10.3390/s25092829 - 30 Apr 2025
Viewed by 458
Abstract
Colorimetric gas sensors are based on a color changing reaction of a sensor dye upon exposure to an analyte. For most sensor applications, the sensor dye must be immobilized in a sensor matrix. The choice of matrix significantly influences the dye’s response due [...] Read more.
Colorimetric gas sensors are based on a color changing reaction of a sensor dye upon exposure to an analyte. For most sensor applications, the sensor dye must be immobilized in a sensor matrix. The choice of matrix significantly influences the dye’s response due to different physical and chemical effects. Ideal matrix materials should be transparent, stable, compatible with the sensor dye, and processable. Polymers are often applied as matrix materials, as they can be easily applied to sensor structures. In this study, we present a method to examine the impact of polymers of different structures and functionalities on sensor dyes. Therefore, 18 polymers are studied in combination with the pH indicator bromocresol green regarding their sensitivity to ammonia. The measurement setup is based on a camera as a detector of the color changing reaction of the sensor materials and allows for the simultaneous measurement of the sensor materials. Furthermore, the response and regeneration time, the stability, and the influence of the environmental parameters humidity and temperature on the colorimetric reaction are investigated. The study demonstrates that polymers as sensor matrices have an influence on the response of sensor dyes, due to their different properties, such as polarity. This has to be considered when choosing a suitable sensor matrix. Full article
(This article belongs to the Collection Optical Chemical Sensors: Design and Applications)
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34 pages, 5540 KiB  
Article
The Use of Biomass-Derived Chitosan for Colorimetric pH Detection
by Ezekiel Edward Nettey-Oppong, Riaz Muhammad, Dohyun Yoo, Sun-Hyeop Hwang, Ahmed Ali, Chacha Saidi Mwita, Hyun-Woo Jeong, Seong-Wan Kim, Young-Seek Seok and Seung Ho Choi
Photonics 2025, 12(3), 231; https://doi.org/10.3390/photonics12030231 - 4 Mar 2025
Cited by 1 | Viewed by 1273
Abstract
This study developed a sustainable colorimetric pH sensor using chitosan derived from mealworm (Tenebrio molitor) biomass and anthocyanin extracted from red cabbage (Brassica oleracea). Chitosan was used as the substrate material, and anthocyanin served as the pH indicator dye, [...] Read more.
This study developed a sustainable colorimetric pH sensor using chitosan derived from mealworm (Tenebrio molitor) biomass and anthocyanin extracted from red cabbage (Brassica oleracea). Chitosan was used as the substrate material, and anthocyanin served as the pH indicator dye, collectively forming the basis of the pH sensor. The resulting pH-responsive film effectively measures pH levels from 1 to 13, with a distinct color shift from pink to green. The sensor demonstrated remarkable stability, maintaining color fidelity after prolonged exposure to aqueous environments, and its practical functionality was confirmed through an ammonia detection assay, underscoring its utility in monitoring food freshness. Mechanistic investigations using Fourier-transform infrared spectroscopy (FTIR) and molecular modeling identified electrostatic and hydrophobic forces as key factors in anthocyanin binding to the chitosan matrix. Molecular modeling further revealed a minimal binding energy of −3 kcal/mol and an RMSD of 0 Å, indicating a strong interaction stability. The film exhibited high structural integrity, with tensile strength and elongation values of 8.8 MPa and 8.4%, respectively, and its flexibility suggests its suitability for diverse applications, including biomedical devices. The eco-friendly production process and the biocompatibility of this sensor provide a sustainable alternative to conventional pH measurement technologies. This innovation not only addresses ecological challenges but also expands the capabilities of colorimetric sensors for use in scientific research, biomedical applications, and other fields. Full article
(This article belongs to the Section Lasers, Light Sources and Sensors)
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16 pages, 3550 KiB  
Article
Investigation of Microbial Fermentation Degree of Pu-Erh Tea Using Deep Learning Coupled Colorimetric Sensor Array via Prediction of Total Polyphenols
by Min Liu, Cui Jiang, Md Mehedi Hassan, Xinru Zhang, Runxian Wang, Renyong Cao, Wei Sheng and Huanhuan Li
Chemosensors 2024, 12(12), 265; https://doi.org/10.3390/chemosensors12120265 - 16 Dec 2024
Viewed by 1147
Abstract
The degree of tea fermentation is crucial as it ultimately indicates the quality of the tea. Hence, this study developed a total polyphenol prediction system for Pu-erh tea liquid using eight porphyrin dyes and one pH dye in a printed colorimetric sensor array [...] Read more.
The degree of tea fermentation is crucial as it ultimately indicates the quality of the tea. Hence, this study developed a total polyphenol prediction system for Pu-erh tea liquid using eight porphyrin dyes and one pH dye in a printed colorimetric sensor array (CSA) coupled with a convolutional neural network (CNN) during microbial fermentation. Firstly, the Box–Behnken sampling method was applied to optimize the degree of microbial fermentation of Pu-erh tea liquid using the response surface methodology. Under optimized conditions, the polyphenol degradation rate reached up to 66.146%. CSA images were then collected from the volatile compounds of Pu-erh tea-reacted CSA sensors. Subsequently, six chemometric approaches were comparatively investigated, and CNN achieved the best results for predicting total polyphenol content. Therefore, the results suggest that the proposed approach can be used to predict the degree of fermentation by measuring total polyphenols in microbial-fermented Pu-erh tea liquid. Full article
(This article belongs to the Special Issue Functional Nanomaterial-Based Sensors for Food Analysis)
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11 pages, 3528 KiB  
Article
A Novel Rhodamine B Fluorescent Probe Derived from Carboxymethyl Chitosan for the Selective Detection of Fe3+
by Mei Yang, Zixi Tang, Chunwei Yu and Jun Zhang
Polymers 2024, 16(22), 3206; https://doi.org/10.3390/polym16223206 - 19 Nov 2024
Viewed by 1181
Abstract
In this study, we synthesized a fluorescent material by modifying the C-2 amino group of carboxymethyl chitosan with a rhodamine B derivative, which was proposed and demonstrated using 1H NMR and FT-IR measurements. A series of experiments including selectivity, sensitivity, reversibility, pH, [...] Read more.
In this study, we synthesized a fluorescent material by modifying the C-2 amino group of carboxymethyl chitosan with a rhodamine B derivative, which was proposed and demonstrated using 1H NMR and FT-IR measurements. A series of experiments including selectivity, sensitivity, reversibility, pH, and water content were conducted to investigate the fluorometric and colorimetric properties of the grafted polymer. Utilizing a Fe3+-induced ring-opening mechanism of the rhodamine B spirolactam, we found that the grafted polymer exhibited a highly selective fluorescence response to Fe3+, with enhanced fluorescence at 583 nm compared to other tested metal ions and anions, accompanied by the characteristic absorption peak of rhodamine B that appeared at 561 nm with a noticeable color change from colorless to pink, facilitating visual observation. Additionally, the modified probe, composed of carboxymethyl chitosan, was easily regenerated through treatment with EDTA. Full article
(This article belongs to the Special Issue Preparation and Application of Biodegradable Polymers)
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15 pages, 6607 KiB  
Article
Effect of Particle Size on Physical Properties, Dissolution, In Vitro Antioxidant Activity, and In Vivo Hepatoprotective Properties of Tetrastigma hemsleyanum Diels et Gilg Powders
by Zhiwen Zhang, Yun Chen, Shaoxian Wang, Zheren Tong, Fujia Luan, Binghong Jiang, Faxiang Pu, Zhangfu Xie, Ping Wang and Zijin Xu
Pharmaceutics 2024, 16(11), 1352; https://doi.org/10.3390/pharmaceutics16111352 - 23 Oct 2024
Cited by 2 | Viewed by 1097
Abstract
Objective: The aim of this study was to analyze the effects of different particle sizes of Tetrastigma hemsleyanum Diels et Gilg (TDG) powders on physical properties, dissolution, in vitro antioxidant activity, and in vivo hepatoprotective properties. Methods: The particle size of TDG coarse [...] Read more.
Objective: The aim of this study was to analyze the effects of different particle sizes of Tetrastigma hemsleyanum Diels et Gilg (TDG) powders on physical properties, dissolution, in vitro antioxidant activity, and in vivo hepatoprotective properties. Methods: The particle size of TDG coarse powders (TDG-CP), TDG fine powders (TDG-FP), and TDG micro powders (TDG-MP) were measured by a laser particle size analyzer. The physical properties were measured according to the latest version of the Chinese Pharmacopoeia (Committee Chinese Pharmacopoeia 2020). The content of the total flavonoids, total polysaccharides, kaempferol-3-O-rutinoside, and rutin of TDG powders were determined using the NaNO2-Al (NO3)3 colorimetric method, the sulphate-phenol colorimetric method, and HPLC, respectively. In vitro dissolution and antioxidant activity were determined by the paddle method in phosphate buffer (pH 6.8) and the DPPH radical scavenging method, respectively. In addition, the liver tissue pathology was evaluated by hematoxylin and eosin staining (H&E), and the AST and ALT activities were measured by automatic biochemical analyzer. The superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) activities were measured by using commercial analysis kits. Results: As the particle size decreases, the fluidity of TDG powders decreased and the porosity increased. In addition, there were no significant differences in physical properties between low temperature pulverized powders and room temperature pulverized powders. The final dissolution rates of the four bioactive ingredients in TDG-MP were found to be 85.06%, 85.61%, 83.88%, and 83.26%, respectively, whereas in TDG-CP, the dissolution rates were significantly lower at 18.79%, 17.96%, 22.46%, and 24.35%. The EC50 values of TDG-CP, TDG-FP, and TDG-MP on DPPH scavenging activity were 0.82, 0.31, and 0.10 mg/mL, respectively. The AST and ALT activities of the TDG-FP group and the TDG-MP group were significantly decreased and the SOD, CAT, and GSH activities were significantly increased when compared with that of the model group. The inflammatory cell infiltration and vacuolar degeneration of liver cells in the TDG-FP group and the TDG-MP group were significantly improved. Conclusions: The particle size of TDG powders had a significant effect on the physical properties and in vivo bioactivity. TDG pulverized to a fine particle size or smaller is a promising approach for clinical applications with improved physicochemical and biological properties. Full article
(This article belongs to the Section Physical Pharmacy and Formulation)
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