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Smart dual-mode fluorescent label from rhodamine–alginate and fluorescein–chitosan for real-time shrimp freshness monitoring
(2026-01-15)
Jitjamrasrat, Aorawee
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Chalitangkoon, Jongjit
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Monvisade, Pathavuth
A dual-mode pH-responsive label was developed for real-time visual monitoring of shrimp freshness. The system integrates oxidized sodium alginate grafted with rhodamine B ethylenediamine (ORE) and chitosan grafted with fluorescein (CSF) into screen-printable inks, forming a dual-color platform with complementary colorimetric and inverse ratiometric fluorescence responses, where ORE emission decreases while CSF emission increases with rising pH. This inverse behavior enhances visual contrast and enables intuitive color discrimination. The label exhibited reversible color transitions—from pink to yellow (daylight) and from bright orange to green (UV) in response to pH and volatile amines showing high sensitivity, selectivity, and storage stability. Applied to shrimp packaging, its optical response correlated with total volatile base nitrogen (TVB-N) levels, effectively distinguishing fresh, sub-fresh, and spoiled samples. RGB analysis using a smartphone enabled rapid, on-site freshness evaluation. This dual-mode, printable sensing platform offers a practical and scalable approach for seafood freshness monitoring and intelligent food packaging.
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Smart colorimetric label based on chitosan-grafted cresol red for early detection of catheter blockage and infection through urinary pH monitoring
(2025-12-01)
Keawdoungdee, Anchisa
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Chalitangkoon, Jongjit
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Sirithanakorn, Chaiyos
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Kamolvit, Witchuda
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Detsri, Ekarat
This study presents a smart, non-invasive colorimetric sensor designed for the early detection of catheter-associated urinary tract infections (CAUTIs) and impending catheter blockage. The sensor was developed by covalently grafting cresol red onto chitosan (CS-g-CR) via a Mannich reaction, producing a biocompatible, pH-responsive material exhibiting strong dye retention and stable, visible color transitions across the urinary pH range. The material was formulated into a water-based screen-printable ink and applied to cotton fabric, yielding flexible labels capable of detecting alkaline shifts associated with Proteus mirabilis infection. In an in vitro bladder model, the printed labels provided up to 20 h of advance warning prior to complete catheter blockage. Color changes were quantified using smartphone-based RGB analysis, enabling objective and real-time monitoring. This low-cost sensing platform holds promise for point-of-care applications aimed at improving early diagnosis and reducing complications in long-term catheterized patients.
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Advanced chitosan hybrid dye labels for dynamic monitoring of shrimp and milk freshness
(2025-04-01)
Ronte, Arnat
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Chalitangkoon, Jongjit
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Sintoppun, Tanaporn
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Niemhom, Nantawan
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Manapradit, Nuttaporn
This study presents the development of intelligent screen-printed labels for real-time food freshness monitoring. Using chitosan grafted with rosolic acid (RA) and immobilized on montmorillonite (MMT) through cationic exchange, a hybrid dye was synthesized and applied in screen-printing inks. The hybrid structure was characterized by XRD, TGA, and UV–vis, confirming improved thermal stability and maintained halochromic properties. SEM analysis showed consistent ink deposition on filter paper, while water contact angle (WCA) measurements demonstrated enhanced surface hydrophobicity due to the MMT. The labels exhibited clear pH-sensitive color transitions from yellow to purplish red (pH 2.0–12.0) and rapid ammonia sensitivity, with ΔE values exceeding 45.0 within 10 min. The labels also demonstrated excellent reversibility, storage stability, leaching resistance, and cytocompatibility. Practical tests on shrimp and milk confirmed the labels' ability to accurately monitor freshness through visible color changes. These findings highlight the potential of hybrid labels as effective, scalable freshness indicators for intelligent food packaging.
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Dual Cross-Linked Chitosan-Based Films with pH-Sensitive Coloration and Drug Release Kinetics for Smart Wound Dressings
(2025-03-04)
Chalitangkoon, Jongjit
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Ronte, Arnat
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Sintoppun, Tanaporn
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Manapradit, Nuttaporn
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Monvisade, Pathavuth
In this study, we developed dual-cross-linked hydrogel films based on carboxyethyl chitosan (CECS) and sodium alginate (SA), utilizing dialdehyde β-cyclodextrin (DA-βCD) and gluconic acid δ-lactone (GDL) as cross-linkers. Designed as smart wound dressings, the films exhibit pH sensitivity due to the incorporation of carboxyethylated phenol red-grafted chitosan (CS-PR-AA), which allows them to change color from orange to purple in response to pH variations. FT-IR and TGA analyses confirmed the formation of imine bonds and polyelectrolyte complexes, indicating successful cross-linking. The films demonstrated high cell viability, confirming their biocompatibility and nontoxicity. The swelling behavior varied with pH, underscoring their adaptability to different wound environments. Additionally, drug release kinetics were studied for films incorporating diclofenac sodium (DCF) at various pH levels, revealing that the release rate was influenced by cross-linking density and environmental pH. These findings suggest that the dual-cross-linked hydrogel films have significant potential as smart wound dressings, offering controlled drug release and pH-responsive behavior suitable for wound care applications.
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Colorimetric Screen-Printed Label Using Low Molecular Weight Chitosan Grafted with Rosolic Acid for pH and Ammonia Gas Sensing
(2024-10-15)
Ronte, Arnat
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Chalitangkoon, Jongjit
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Monvisade, Pathavuth
Colorimetric sensing technologies are valued for their simplicity and adaptability, yet their large-scale production remains economically challenging. This study presents a cost-effective colorimetric pH sensor developed from low molecular weight chitosan (LC) grafted with rosolic acid (LCRA), engineered as a pH-sensitive colorant for screen-printing inks. LCRA was synthesized via a Mannich reaction and characterized using<sup>1</sup> H NMR, FT-IR, and UV-Vis spectroscopy. LCRA showed reduced crystallinity and thermal stability alongside notable improvements in water solubility compared to its LC precursor. The LCRA ink displayed compatibility with various substrates, including polypropylene spun bond, filter paper, and cotton, applying easily via screen printing without any dye leaching. Notably, it exhibited a responsive color change from orange-yellow to pink-red in response to pH adjustments between 4.0 and 12.0 and upon exposure to ammonia gas. These findings position the LCRA label as a versatile and efficient solution for visual pH detection across various applications.
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Antimicrobial nanolayer films of chloroxylenol–carboxyethylchitosan–modified silver nanoparticles for enhanced surgical suture performance
(2024-07-20)
Chittratan, Pakawat
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Detsri, Ekarat
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Chalitangkoon, Jongjit
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Mathaweesansurn, Arjnarong
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Monvisade, Pathavuth
Antimicrobial surgical suture materials incorporating chloroxylenol-carboxyethylchitosan-modified silver nanoparticles (CECSX-AgNPs) were successfully prepared using the Layer-by-Layer (LbL) deposition technique. Chitosan (CS) was covalently affixed with chloroxylenol as hydrophobic functional groups (PCMX), yielding chloroxylenol-chitosan (CSX) and later hydrophilic acrylic acid onto the CSX skeleton, providing a novel water-soluble antimicrobial agent of chloroxylenol-carboxyethylchitosan (CECSX). <sup>1</sup>H NMR confirmed the successful substitution of PCMX and acrylic acid onto CS, with %DS<inf>PCMX</inf> and %DS<inf>AA</inf> of 8.0 and 33.0, respectively. CECSX successfully stabilized AgNPs via the chemical reduction method, resulting in CECSX modified AgNPs. The colloidal solution exhibited a yellowish hue, spherical shape, monodispersity with an average particle size of 4.8 ± 2.4 nm, and a zeta potential value of −20.97 ± 0.03 mV. Minimum inhibitory concentration (MIC) values for CECSX-AgNPs against E. coli (ATCC25922), S. aureus (ATCC25923), and A. baumanii (ATCC19606) were determined as 25, 12.5, and 1.56 mg/L, respectively. Using the LbL deposition technique, CECSX-AgNPs were successfully deposited onto various suture materials including cotton, polyamide, and polypropylene. Remarkably, CECSX-AgNPs coated surgical sutures exhibited the highest bacterial reduction of 99.99 %. These findings underscore the efficacy of CECSX as a high-performance stabilizing agent for AgNPs production, providing outstanding antibacterial activity on diverse surgical suture materials and promoting the wound healing process.
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Development of a pH-responsive intelligent label using low molecular weight chitosan grafted with phenol red for food packaging applications
(2024-05-01)
Ronte, Arnat
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Chalitangkoon, Jongjit
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Foster, E. Johan
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Monvisade, Pathavuth
In this study, we successfully developed a screen-printed pH-responsive intelligent label using low molecular weight chitosan grafted with phenol red (LCPR) as a colorant for screen printing ink. The LCPR was synthesized via a Mannich reaction, and its successful grafting was confirmed through FT-IR, UV–vis, and NMR spectroscopy. The LCPR exhibited lower crystallinity and thermal stability compared to low molecular weight chitosan (LC) and demonstrated zwitterionic behavior. To create intelligent labels, the LCPR-based ink was efficiently printed on cotton substrates with high resolution. The label exhibited remarkable sensitivity to buffer pH solutions and ammonia gas, leading to distinctive color changes from orange to red to purple. Additionally, the label showed excellent reversibility, storage stability, and leaching resistance to different food simulant solutions. The label was utilized to monitor shrimp freshness, successfully detecting a noticeable color shift upon spoilage. These findings highlight the significant potential of the LCPR-based label as an intelligent food packaging solution, offering pH-responsiveness and color stability for qualitative freshness detection of protein-rich food.
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Improving the Fluorescence of Carbon Dots Through Boron and Silver Doping: A Single-Step Microwave Synthesis Approach
(2024-04-15)
Sakboriboon, Yanika
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Chalitangkoon, Jongjit
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Monvisade, Pathavuth
Carbon dots (CDs) are a promising type of fluorophore with numerous advantages such as low toxicity, biocompatibility, good photostability, and ease of synthesis. However, their low quantum yields (QYs) have limited their applicability in many fields. Researchers have turned to doping CDs with nonmetallic and metallic atoms to address this issue. In this study, we synthesized citric acid/urea-based CDs doped with boron and/or silver atoms in a single step using microwave irradiation. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the CDs. In contrast, UV-visible (UV-Vis) and fluorescence spectroscopy were used to examine their optical properties. We discovered that all synthesized CDs were transparent to visible light and emitted blue fluorescence when exposed to UV light. Our fluorescence analysis revealed that doping with both boron and silver atoms led to higher fluorescence compared to doping with only one of the atoms. Specifically, the quantum yields (QYs) of silver/boron-doped CDs were 26%, which is higher than those of silver-doped CDs (19%), boron-doped CDs (9%), and undoped CDs (6%). These findings suggest that the silver/boron-doped CDs produced using our simple method could be promising materials for sensors and biomedical applications.
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Carboxyethylation of chitosan-based polymeric dyes for potential pH-sensing applications
(2023-08-01)
Chalitangkoon, Jongjit
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Ronte, Arnat
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Monvisade, Pathavuth
Background: Polymeric dyes have gained significant attention due to their unique properties and potential applications in various fields. Previous research has shown that chitosan-based polymeric dyes (CSPDs) had excellent color-sensing characteristics, but they had a solubility limitation. Methods: CSPDs were modified by the Michael reaction of acrylic acid in mild conditions. The synthesized derivatives were characterized using various analytical techniques, including FTIR, NMR, and UV–vis. Their crystallinity, thermal properties and solubility were also investigated. Significant findings: The presence of new carboxyethyl groups in novel water-soluble chitosan-based polymeric dyes (WCSPDs) after the modification was confirmed, without affecting their coloring. The derivatives also showed lower crystallinity, making them soluble in water over a wide range of pH values, and exhibited lower thermal stability. Furthermore, the derivatives displayed coloring properties and were nontoxic. These properties suggested the potential use of WCSPDs as sensor materials. In summary, the findings of this study highlighted the potential of WCSPDs as novel polymeric dyes with unique properties that could have significant applications in diverse fields, such as sensing and biomedical engineering.
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Self-healing hydrogels based on sodium carboxymethyl cellulose/poly(Vinyl alcohol) reinforced with montmorillonite
(2022-08-15)
Weerawan, Nicharee
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Chalitangkoon, Jongjit
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Monvisade, Pathavuth
Currently, self-healing hydrogels prepared from the green process have been studied for various applications, especially in the biomedical field. This work fabricated the self-healing hydrogel based on sodium carboxymethyl cellulose/poly(vinyl alcohol)/montmorillonite by acidifying the mixture with citric acid. SEM measurements showed well-dispersed montmorillonite in the hydrogels. Cytotoxicity values >100% were seen with montmorillonite added, which indicated cell growth and no cell toxicity. Montmorillonite addition not only reinforced the networks but also improved self-healing ability. The tensile strength of the original uncut hydrogel with montmorillonite (P1C8M1) was 61 kPa, whereas the healed hydrogel showed 57 kPa. The hydrogel healed completely within 10 days, without any cracks, i.e., a 93% healing efficiency, or higher than the ~60% of the non-reinforced hydrogel. This confirmed strong hydrogen bond formation between the polymer and montmorillonite. The self-healing ability of this non-toxic hydrogel, reinforced with montmorillonite, makes it valuable for use in biomedical fields.

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