Sutthira Sutthasupa

The development of noninvasive diagnostic platforms for biomarker detection in complex biological fluids remains a significant challenge. Herein, we report a biomolecule-inspired, metal-ion-free polymeric fluorescence chemosensor in which polymer architecture governs molecular recognition and photophysical response, enabling ultrasensitive detection of arginine (Arg), a clinically relevant biomarker for metabolic and renal disorders. Based on a coumarin–tyrosine-functionalized polynorbornene synthesized via ring-opening metathesis polymerization (ROMP), the system integrates recognition sites within a well-defined macromolecular framework. UV–vis studies reveal a bathochromic shift (350–442 nm) with an isosbestic point at 392 nm upon Arg binding. Both Poly-Cou-Tyr-Boc and Poly-Cou-Tyr-NH2 exhibit ratiometric fluorescence behavior in DMSO. The polymeric architecture affords enhanced signal amplification over monomeric analogues, achieving a limit of detection (LOD) of 71.42 nM and 103.64 nM, respectively. Systematic evaluation established artificial saliva as the optimal medium due to negligible matrix interference. In this environment, the probes demonstrated matrix-dependent fluorescence sensing. Poly-Cou-Tyr-Boc maintained ratiometric performance, while the deprotected Poly-Cou-Tyr-NH2 functioned via high-sensitivity intensity-based quenching at 411 nm. This dual-mode capability yielded exceptional LODs of 33.09 nM and 32.45 nM in saliva, respectively. Mechanistic studies, including 1H NMR titration and Job’s plot, confirmed a 1:1 interaction mediated by cooperative hydrogen bonding. This work establishes a structure–property-driven polymer design strategy, providing a versatile metal-ion-free platform for next-generation noninvasive diagnostics and real-time metabolic monitoring.

This study aims to develop sugarcane bagasse-derived granular activated carbon (SCB-GAC) as a biobased adsorbent for methylene blue (MB) adsorption in an aqueous solution using a binderless hot-pressed (HP) technique. HP conditions, i.e., mechanical pressure, temperature, and holding time, were systematically fine-tuned to first produce HP-SCB pellets. HP pellets were further carbonized at 500 °C for 1 h to obtain biochar pellets, which were cut into granules prior to activation with steam under the optimum conditions of 850 °C for 30 min. The mechanical pressure showed the most significant influence on the yield and textural properties of the as-developed HP-SCB-GAC. The optimal HP condition of 20 MPa at 270 °C for 30 min resulted in a substantial yield (53.7%) of the developed HP-SCB-GAC with uniform surface texture possessing the highest strength and specific surface area (804.6 m²/g). The MB adsorption using the selected HP-SCB-GAC showed minimal sensitivity to pH adjustments. The maximum MB adsorption capacity at approximately 138 mg/g could be achieved and fitted with the pseudo-second-order kinetic model and Langmuir equilibrium isotherm behaviors. The selected HP-SCB-GAC could reach as high as 87–92% of MB adsorption efficiency for at least five consecutive cycles using ethanol as the regenerant.

Stimuli-responsive polymeric micelles offer promising platforms for biomedical applications, yet achieving precise control over thermoresponsive behavior and fluorescence remains a challenge. In this study, we synthesized Poly­(NB-Prol- block- Oxa-Trp) diblock copolymers via ROMP, incorporating proline (NB-Prol) for thermoresponsiveness and the inherent fluorescence of tryptophan (Oxa-Trp). Unlike conventional thermoresponsive systems, this design leverages the dual functionality of natural amino acid motifs without the need for external dyes or labels. By adjusting segment length, we achieved tunable lower critical solution temperatures (LCSTs) and fluorescence properties, which influenced micelle self-assembly and stability. Our results confirm micelle formation in a selective solvent (DMSO:H₂O), as the fluorescence intensity decreased with increasing water content. The self-assembled micelles (90–290 nm) exhibited temperature-dependent shrinkage (15–45 °C) and aggregation (50–65 °C) due to enhanced hydrophobicity. Cytotoxicity studies across multiple cell lines demonstrated biocompatibility, while preliminary doxorubicin hydrochloride (DOX·HCl) loading supported their potential in stimuli-triggered or pulsatile drug release systems. This study provides insights into optimizing polymeric micelles as intelligent nanocarriers and lays the foundation for their future biomedical integration.

We present a novel group of tryptophan (Trp)-based fluorescent polymeric probes synthesized via ring-opening metathesis polymerization (ROMP) of Trp-derived norbornene monomers. These probes, in mono- and disubstituted forms, incorporate amide and ester anchoring groups. The quantity of Trp substituents did not affect fluorescence selectivity but influenced quenching percentage. Poly-diamide-Trp, Poly-monoamide-Trp, Poly-diester-Trp, and Poly-monoester-Trp probes displayed selective detection of Fe²⁺ and Fe³⁺ ions with fluorescence on-off characteristics. Poly-diamide-Trp and Poly-monoamide-Trp exhibited a limit of detection (LOD) for Fe²⁺ and Fe³⁺ ions of 0.86-11.32 μM, while Poly-diester-Trp and Poly-monoester-Trp showed higher LODs (21.8-108.7 μM). These probes exhibited high selectivity over Fe²⁺, a crucial metal ion in the body known for its redox properties causing oxidative stress and cell damage. Cell cytotoxicity tests in various cell types confirmed biocompatibility. Additionally, Poly-diamide-Trp displayed excellent cell permeability and iron ion detection in EA.hy926 cells, suggesting potential for bioimaging and clinical applications.

A hydrogel-based colorimetric oxygen indicator that exhibits high photoreduction efficiency and fast oxygen response was produced by integrating ZnO nanoparticles and a redox dye into an alginate hydrogel matrix. We found that varying the ZnO and glycerol [external sacrificial electron donor (SED)] content significantly affected the swelling behavior and strength of the hydrogels. We also found that retained water molecules and glycerol in the hydrogel serve as good electron donors, whereas ZnO nanoparticles are effective photocatalysts that affect the decoloration. By irradiating the hydrogel with UV light for 20 min, the UV intensity can induce the acceleration of the ZnO nanoparticles, creating photogenerated pores that are captured by the SEDs. Consequently, the photogenerated electrons rapidly reduced methylene blue to leuco-methylene blue, causing a color change from blue to colorless. Utilizing their porous network structures that facilitate oxygen diffusion, the hydrogel-based oxygen indicators exhibit fast recoloration (∼3 min) under a continuous ambient air (20 vol% O₂ in nitrogen gas) flow rate of 500 mL min⁻¹. The repeatability performance was improved by glycerol, illustrating the role of the external SED in our hydrogel-based oxygen indicator. We believe that the current study highlights the potential for the development of stimuli-responsive hydrogels as colorimetric oxygen-sensing materials.

Encapsulation of clove, lavender essential oils (EOs)m and vanillin into chitosan (CH) and alginate (AL) beads was prepared using a simple oil‐entrapped emulsion to inhibit Botrytis cinerea in table grapes. The overall encapsulation efficiency of AL beads was observed to be higher than that of CH beads. The release of EO from beads depended mostly on surrounding relative humidity. The inhibition efficiency of the beads was investigated with grapes packed in a clamshell by placing a permeable sachet containing beads inside and storing at 5°C for 28 days. Visible mould growth on the control grapes and grapes packed with CH beads containing clove EO was observed on Days 21 and 28, respectively. The grapes packed with AL beads containing clove EO were free from mould until Day 28. The qualities of the grapes during storage, including the CO₂ and O₂ concentration in the packaging, firmness, total soluble solids, titratable acidity, ascorbic acid content, and acceptability of grapes, were evaluated. The use of CH or AL beads releasing clove EO maintained the freshness, firmness, flavour, odour, and overall acceptability of the grapes better than the control.