Teerasong, Saowapak

Loading...
Thumbnail Image
Preferred name
Teerasong, Saowapak
Alternative Name
Teerasong, S.
Main Affiliation
Email
saowapak.te@kmitl.ac.th

Settings

Now showing 1 - 4 of 4
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    A scanner-based microplate platform for high-throughput oxytetracycline detection using diazotization-coupling chemistry with greenness evaluation
    (2026-06-01)
    Puttasa, Papawarin
    ;
    Ngernpimai, Sawinee
    ;
    Tippayawat, Patcharaporn
    ;
    Park, Myoung‑Hwan
    ;
    Teerasong, Saowapak
    Routine oxytetracycline (OTC) monitoring of aquaculture effluents, water sources, and pharmaceutical products is essential for environmental management and regulatory compliance. However, existing analytical methods remain largely instrumental and low-throughput. Herein, a microvolume, high-throughput, scanner-based colorimetric microplate platform is developed for OTC determination using a sensitive and selective diazotization-coupling chemistry with RGB digital image analysis. Sulfanilamide is diazotized with nitrite to generate reactive diazonium species, which subsequently couple with OTC to form a strongly colored yellow-orange azo dye. Only microliter-scale volumes of reagents and samples are required in each well, and the reaction is completed within a few minutes, enabling simultaneous analysis of up to 96 samples. The microplate is imaged with a flatbed scanner, and color responses are quantified using ImageJ software. A linear calibration range of 1 − 40 μM was obtained with a detection limit of 0.33 μM. The platform was successfully applied to OTC determination in aquaculture effluents, tap water, drinking water, and pharmaceutical samples. It exhibited high selectivity against other antibiotics with no observable cross-reactivity. The green analytical procedure index (GAPI) confirmed the method’s environmental friendliness. Overall, the scanner-based microplate platform offers a simple, low-cost, portable, and high-throughput alternative to conventional OTC assays.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Insight into the Covalently Oriented Immobilization of Antibodies on Gold Nanoparticle Probes to Improve Sensitivity in the Colorimetric Detection of Listeria monocytogenes
    (2022-11-16)
    Ngernpimai, Sawinee
    ;
    Srijampa, Sukanya
    ;
    Thongmee, Patsara
    ;
    Teerasong, Saowapak
    ;
    Puangmali, Theerapong
    In this work, the covalently oriented conjugation of monoclonal Listeria monocytogenes antibody (mAb-Lis) to amino-terminated oligo(ethylene glycol)-capped gold nanoparticles (NH<inf>2</inf>-TEG-AuNPs) was studied. After NH<inf>2</inf>-TEG-AuNPs were synthesized, the amino-terminated ligands on the particles were then linked to the carboxyl groups in the mAb-Lis through EDC/NHS chemistry. By maintaining the pH of the solution at ∼5, the Fc region of the antibody could preferably attach to the particle surface, providing a specific Fab region that was available for binding with the target pathogen. The resulting mAb-NH-TEG-AuNPs could act as a colorimetric probe for L. monocytogenes based on a particular antigen-antibody interaction, which resulted in a drastic aggregation of particles. This caused the color of the colloidal solution to transition from red-pink to purple or even gray depending on the pathogen concentration. To perform quantitative analysis, the absorbance ratio of A<inf>650</inf>/A<inf>534</inf>was monitored as a function of L. monocytogenes concentration using a spectrophotometer. The detection limit was very low at 11 CFU/mL. Furthermore, a lateral flow strip (LFS) was fabricated as a portable device for onsite utilization. LFS detection could be completed by the naked eye and by a smartphone. The detection limit of LFS was estimated to be 10<sup>3</sup>CFU/mL. Our methods exhibited a substantial improvement in sensitivity compared to that of previous studies on immuno-based nanoparticles. The assay could be completed in 15 min, and no cross reactivity by any pathogen was found. Hence, the designed AuNPs exhibit great promise for use in monitoring L. monocytogenes for food safety and in other applications.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Enhanced Stability of Gold Nanoparticles with Thioalkylated Carboxyl-Terminated Ligands for Applications in Biosensing
    (2024-06-14)
    Ngernpimai, Sawinee
    ;
    Puangmali, Theerapong
    ;
    Kopwitthaya, Atcha
    ;
    Tippayawat, Patcharaporn
    ;
    Chompoosor, Apiwat
    Gold nanoparticles (AuNPs) are widely recognized for their remarkable optical and chemical properties, making them versatile materials with diverse applications in sensing, catalysis, and biomedical fields. However, their susceptibility to aggregation and poor dispersion under different environmental stresses limits their utility in practical applications. In this study, we investigate the efficacy of utilizing carboxylate-terminated ligands to stabilize AuNPs and enhance their stability and functionality. Through a series of experiments, including assessments of pH buffer effects, ionic strength variations, freeze-drying stress, and protein adsorption, we demonstrate the effectiveness of these ligands in maintaining the stability of AuNPs within a pH range of 5-10. This enables them to resist aggregation in the presence of high concentrations of electrolytes and facilitates rapid redispersion after freeze-drying, enabling long-term storage of AuNPs in a dry powder form without compromising their stability or functionality. Moreover, the ligands efficiently prevent nonspecific protein binding. We explore application of these stabilized AuNPs conjugated with specific monoclonal antibodies for detection of Listeria monocytogenes, highlighting their potential for use in biosensing applications. This research underscores the significance of carboxylate-terminated ligands in stabilizing AuNPs, offering insights into the development of reliable and functional nanomaterials for various biomedical and biosensing applications.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    The Evaluation of a Lateral Flow Strip Based on the Covalently Fixed “End-On” Orientation of an Antibody for Listeria monocytogenes Detection
    (2024-05-28)
    Thongmee, Patsara
    ;
    Ngernpimai, Sawinee
    ;
    Srichaiyapol, Oranee
    ;
    Mongmonsin, Urairat
    ;
    Teerasong, Saowapak
    In this study, the covalently fixed “end-on” orientation of a monoclonal Listeria monocytogenes antibody (mAb-Lis) to amino terminated oligo (ethylene glycol)-capped gold nanoparticles (NH<inf>2</inf>-TEG-AuNPs) was used to fabricate an in-house lateral flow strip (LFS), namely, the fixed “end-on” Lis-mAb-NH-TEG-AuNPs LFS. The aim was to evaluate the performance of the fixed “end-on” Lis-mAb-NH-TEG-AuNPs LFS in detecting L. monocytogenes. The proposed LFS enabled the sensitive detection of L. monocytogenes in 15 min with a visual limit of detection of 10<sup>2</sup> CFU/mL. Quantitative analysis indicated an LOD at 10 CFU/mL. The fixed “end-on” Lis-mAb-NH-TEG-AuNPs LFS showed no cross-reactivity with other pathogenic bacteria and practical performance across different food matrices, including human blood, milk, and mushroom samples. Furthermore, the clinical performance of the fixed “end-on” Lis-mAb-NH-TEG-AuNPs LFS for detecting L. monocytogenes was evaluated by using 12 clinical samples validated by the hemoculture method. It demonstrated excellent concordance with the reference methods, with no false-positive or false-negative results observed. Therefore, the fixed “end-on” Lis-mAb-NH-TEG-AuNPs LFS serves as a promising candidate for a point-of-care test (POCT), enabling the rapid, precise, and highly sensitive detection of L. monocytogenes in clinical samples and contaminated food.