Automated fluorimetric sensor for glutathione based on zone fluidics

Tsiasioti, Apostolia; Iakovidou, Ifigenia; Zacharis, Constantinos K.; Tzanavaras, Paraskevas D.

doi:10.1016/j.saa.2019.117963

Cited by 11 publications

(12 citation statements)

References 27 publications

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“…The results indicated that no significant difference (at the 95% confidence level) between the two models was observed (t = 0.367 < t critical ). The t 90 (time required to degrade 10% of the drug-often interpreted as the shelf-life under the specific experimental conditions) and t 1/2 (time required to degrade 50% of the drug) values were calculated as follows: t 1/2 = ln2 k = 0.693 k = 38.5 min (HPLC) (5) t 90 = ln1.11 k = 0.104 k = 5.8 min (HPLC) (6) and confirmed the instability of GSH under oxidative conditions.…”

Section: Oxidative Forced Degradation Results and Kineticsmentioning

confidence: 99%

“…As mentioned above, the oxidative forced degradation of GSH was also examined by an in-house developed and validated automated flow method [6]. Due to the unique mechanism of the OPA-GSH reaction the automated flow-based protocol offers unique selectivity and more than adequate sensitivity for the selected application.…”

Section: Opa-based Zone Fluidics Methodsmentioning

confidence: 99%

“…Derivatization of GSH does not only enhance its detectability (UV-Vis or fluorescence), but it also stabilizes the analyte and improves its chromatographic behavior under reversed-phase conditions. Among others, o-phthalaldehyde (OPA) seems to be an advantageous derivatization reagent since it reacts fast and selectively with GSH to form a fluorescent tricyclic derivative, under mild conditions, and it is commercially available at a low purchase cost [6]. Alternatively, derivatization can be avoided by direct detection of GSH at the low UV region (λ = 200-220 nm) combined with a suitable separation technique.…”

Section: Introductionmentioning

confidence: 99%

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Study of the Oxidative Forced Degradation of Glutathione in Its Nutraceutical Formulations Using Zone Fluidics and Green Liquid Chromatography

et al. 2020

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In the present study, we report the results of our investigation of the oxidative forced degradation of glutathione in its nutraceutical formulations by two validated analytical methods. The first is based on the reaction of glutathione with o-phthalaldehyde through an automated zone fluidics flow platform and fluorimetric detection (λ ex /λ em = 340/425 nm). The second is based on the separation of glutathione and its oxidation product by a green reversed-phase HPLC method coupled to direct UV detection, at 210 nm. A solution of 3% w/v H 2 O 2 provided fast oxidation of more than 95% of glutathione to yield oxidized glutathione in a time period of 180 min. The mechanism of the oxidation was proved to follow pseudo-first order kinetics. The k, t 90 and t 1/2 values were calculated.

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Section: Oxidative Forced Degradation Results and Kineticsmentioning

confidence: 99%

Section: Opa-based Zone Fluidics Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of the Oxidative Forced Degradation of Glutathione in Its Nutraceutical Formulations Using Zone Fluidics and Green Liquid Chromatography

et al. 2020

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“…(iii) Histamine and Glutathione seem to cause the most serious interference at equimolar levels to HIS. Both compounds are known to react with the tagging reagent in the absence of nucleophilic compounds, yielding fluorescent derivatives [22,24]. However, the selectivity factors of ca.…”

Section: Selectivity and Matrix Effectmentioning

confidence: 99%

“…The above-mentioned reaction is promising since it proceeds without the need of nucleophilic compounds and is therefore selective against numerous primary amino-group containing analytes that react with OPA through the traditional mechanism [20]. Additionally, histamine that is structurally analogous form an unstable derivative at alkaline medium requiring acidification prior to detection [21], while glutathione reacts with OPA at a significantly more basic pH [22].…”

Section: Introductionmentioning

confidence: 99%

Fluorimetric Method for the Determination of Histidine in Random Human Urine Based on Zone Fluidics

et al. 2020

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In the present study, the determination of histidine (HIS) by an on-line flow method based on the concept of zone fluidics is reported. HIS reacts fast with o-phthalaldehyde at a mildly basic medium (pH 7.5) and in the absence of additional nucleophilic compounds to yield a highly fluorescent derivative (λex/λem = 360/440 nm). The flow procedure was optimized and validated, paying special attention to its selectivity and sensitivity. The LOD was 31 nmol·L−1, while the within-day and day-to-day precisions were better than 1.0% and 5.0%, respectively (n = 6). Random urine samples from adult volunteers (n = 7) were successfully analyzed without matrix effect (<1%). Endogenous HIS content ranged between 116 and 1527 μmol·L−1 with percentage recoveries in the range of 87.6%–95.4%.

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Dual‐Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor‐Resident Intracellular Bacteria

Kang

Feng

et al. 2022

Advanced Materials

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The limited drug penetration and robust bacteria‐mediated drug inactivation in pancreatic cancer result in the failure of chemotherapy. To fight against these issues, a dual‐cascade responsive nanoparticle (sNP@G/IR) that can sequentially trigger deep penetration, killing of intratumor bacteria, and controlled release of chemo‐drug, is reported. sNP@G/IR consists of a hyaluronic acid (HA) shell and glutathione (GSH)‐responsive polymer‐core (NP@G/IR), that encapsulates gemcitabine (Gem) and photothermal agent (IR1048). The polymer core, as an antibiotic alternative, is tailored to exert optimal antibacterial activity and selectivity. sNP@G/IR actively homes in on the tumor due to the CD44 targeting of the HA shell, which is subsequently degraded by the hyaluronidase in the extracellular matrix. The resultant NP@G/IR in decreased size and reversed charge facilitates deep tumor penetration. After cellular endocytosis, the exposed guanidine on NP@G/IR kills intracellular bacteria through disrupting cell membranes. Intracellular GSH further triggers the controlled release of the cargo. Thus, the protected Gem eventually induces cell apoptosis. Under laser irradiation, the hyperthermia of IR1048 helps further elimination of tumors and bacteria. Moreover, sNP@G/IR activates immune response, thereby reinforcing anticancer capacity. Therefore, this dual‐cascade responsive sNP@G/IR eliminates tumor‐resident intracellular bacteria and augments drug delivery efficacy, providing a new avenue for improving cancer therapy.

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Automated fluorimetric sensor for glutathione based on zone fluidics

Cited by 11 publications

References 27 publications

Study of the Oxidative Forced Degradation of Glutathione in Its Nutraceutical Formulations Using Zone Fluidics and Green Liquid Chromatography

Study of the Oxidative Forced Degradation of Glutathione in Its Nutraceutical Formulations Using Zone Fluidics and Green Liquid Chromatography

Fluorimetric Method for the Determination of Histidine in Random Human Urine Based on Zone Fluidics

Dual‐Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor‐Resident Intracellular Bacteria

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