Rapid determination of L-ascorbic acid content in vitamin C serums by ultra-high-performance liquid chromatography-tandem mass spectrometry

A sensing platform for ascorbic acid based on the spatial confinement of covalent organic frameworks

Essential to many activities in our bodies, ascorbic acid is a small molecule essential to human health and physiological processes. In this study, a covalent organic framework called TpNda-COF was synthesized, which is composed of Tp (triformylephloroglucinol) and Nda (1, 5-napthalenediamine). This framework acts as a mimic enzyme and displays excellent oxidase-like activity when stimulated with purple light (at = 405 nm). It catalyzes the oxidation of 3,3',5,5'-tetramethylbenzydine (TMB) by generating O2- free radicals in the presence of oxygen. The resulting oxTMB shows a characteristic absorption peak at 652 nm. The biomimetic catalysis efficiency is significantly improved due to spatial restriction. By introducing ascorbic acid (AA) in the system, the blue oxTMB is reduced to colorless TMB. The decrease in absorption peak intensity can be quantitatively measured using a UV-Vis spectrophotometer, enabling the detection of AA. The sensing platform demonstrates excellent selectivity and sensitivity. It has a wide linear detection range from 5 μM to 50 μM, with a low detection limit of 1.44 μM. Advantages such as the easy control of light, high stability and efficient oxidation are provided by the TpNda-COF mimic oxidase. This innovative method presents a promising and cost-effective approach for rapid detection of ascorbic acid, with potential applications across various fields.

Unlocking the potential of cosmetic dermal delivery with ethosomes: A comprehensive review

BACKGROUND

In a world where hair loss, acne, and skin whitening are common concerns, ethosomes emerge as a captivating breakthrough in cosmetic drug delivery.

METHOD

This review provides a comprehensive overview of the ethosomal system and assesses its potential as an effective nanocarrier for delivering active ingredients to the skin. The focus is on exploring their applications in various pathologies, particularly skin disorders such as acne, hair loss, and skin pigmentation.

RESULTS

Ethosomes are a novel type of vesicular nanocarrier composed of high concentrations of ethanol (20-45%) and phospholipids. Their unique structure and composition make them an ideal choice for transporting active ingredients through the skin, offering targeted and effective treatment. The inclusion of ethanol in ethosomes' composition gives them distinctive properties, including flexibility, deformability, and stability, facilitating deep penetration into the skin and enhancing medication deposition. Moreover, ethosomes improved theoverall drug-loading capacity, and specificity of target treatment CONCLUSION: Ethosomes represent a unique and suitable approach for delivering active cosmetic ingredients in the treatment of hair loss, acne, and skin whitening, presenting a versatile alternative to traditional dermal delivery systems. Despite the challenges associated with their complex preparation and sensitivity to temperature and humidity, the remarkable potential benefits of ethosomes cannot be ignored. Further research is crucial to unlock their full potential, understand their limitations, and refine their formulations and administration methods. Ethosomes hold the promise of transforming the way we address these cosmetic concerns, offering an exciting glimpse into the future of advanced skincare solutions.

A pre-oxidized Eu-probe doped into bio-MOF-1 for ascorbic acid emission "off-on" detection in human serum

Ascorbic acid (or widely known as vitamin C, VC) is an essential antioxidant and a free radical scavenger in human body. The appeal for reliable fluorescent nanosensors always promotes the development of VC probe. In this work, a pre-oxidized Eu-probe (denoted as Eu-NO9) was synthesized. Without VC, Eu-NO9 was nearly non-emissive owing to the inefficient ligand energy transfer (ET) to Eu ion (caused by mismatched ligand level and long distance to Eu, as revealed by single crystal analysis and emissive parameters). By adding VC, the pre-oxidized ligand was deoxidized and its ET to Eu ion became efficient (confirmed by electrochemical analysis), with Eu(III) red emission intensity obviously increased. Then Eu-NO9 was doped into a porous host bio-MOF-1 for ascorbic acid detection (denoted as Eu-NO9@MOF). The molecular sieving effect of bio-MOF-1 improved sensing selectivity, and bio-MOF-1 blue emission (421 nm) was applied as a reference for Eu(III) red emission. Linear working curves were obtained within a wide working region of 0-100 μM, with LOD of 1.7 μM. A short response time of 192 s at 25 °C was confirmed. Practical sensing plates were prepared and found applicable for VC detection in fresh human serum. The advantage of this work was the combination of a pre-oxidized probe and a porous host which gave emission "turn on" fluorescence sensing for VC with good selectivity, linear calibration curve and wide working region.

Ni3V2O8 nanoflower mimetic enzyme constructs a dual-signal system for ascorbic acid detection

Ascorbic acid is a nutritional small molecule essential to human life activities and health, playing a vital role in many physiological processes. Fresh fruits and beverages can provide abundant AA to maintain human metabolic balance. Therefore, it is of great significance to develop a nanomaterial with superior nanozyme activity for rapid and convenient detection of ascorbic acid (AA) in fruits and beverages. Herein, a dual-signal sensing platform based on UV-vis absorption and test strip chromaticity for the quantitative determination of AA is presented. The sensing platform is based on the horseradish peroxidase-like activity of Ni3V2O8 nanoflowers, which catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide to the blue oxide TMB (ox TMB). The ox TMB produced by the oxidation has a characteristic absorption peak at 650 nm. In the presence of AA, the blue ox TMB is reduced to colorless TMB, and the quantitative detection of AA can be achieved by detecting the decrease in intensity of the absorption peak by UV-Vis spectrophotometry. Under the optimal experimental conditions, the sensing platform exhibited excellent sensitivity and selectivity. A wide linear range of 0.1 μM to 40 μM with a detection limit of 0.032 μM was obtained. The linear equation is ΔA = 0.02513c + 0.1164 with a correlation coefficient of 0.9979. It showed excellent properties in the detection of real samples of fruit juices and beverages, meanwhile, a method for the rapid detection of AA based on chromaticity change of test strips was constructed with high sensitivity and convenience. The linearity range for the ascorbic acid was 1-50 μM with LOD of 0.42 μM. The developed sensing platform has the capability to quickly and accurately detect ascorbic acid (AA) in fresh fruits and beverages. This proposed method offers a new and promising approach for the rapid and cost-effective detection of ascorbic acid, which has a wide range of potential applications.

Kinetic spectrophotometric assay for the determination of vitamin C in cosmetics following ultrasound-assisted emulsification

In this work, a new analytical approach based on ultrasound-assisted emulsification followed by a photoreaction with methylene blue (MB) and kinetic analysis by UV-vis spectrophotometry has been developed for the determination of L-ascorbic acid (AA) in cosmetic samples. The emulsification of cosmetic samples results in a transparent solution that allows an easy and rapid quantitation by UV-vis spectrophotometry. The emulsified sample is mixed with a MB aqueous solution and this mixture is subjected to irradiation with a tungsten lamp for 5 min (fixed-time kinetic assay). A reduction in the MB absorbance intensity at 664 nm occurs as the concentration of AA increases. The observed change in absorbance intensity was used for calibration and further quantitation using the relationship of absorbance logarithm vs. AA concentration (μg mL^-1). In order to achieve an optimal response, different parameters involved in the reaction between AA and MB were fully investigated. Under optimal conditions, the limits of detection and quantification were 0.04 μg mL^-1 and 0.15 μg mL^-1, respectively. Repeatability and reproducibility, expressed as relative standard deviation, were in the range of 0.4-0.6% and 0.6-1.5%, respectively. Finally, the proposed method was applied to the analysis of 15 cosmetic samples, namely, (i) 12 samples without AA, which were used to carry out recovery studies, obtaining results in the range of 97.5-100.7%; (ii) 3 serum samples containing pure AA among their ingredients, which were used for AA stability studies.

A Comprehensive Study: Traditional and Cutting-Edge Analytical Techniques for the Biomarker Based Detection of the Micronutrients & POC Sensing Directions for Next-Generation Diagnostic

Micronutrient deficiency is wide spread and highly affects morbidity, mortality, and well-being of human beings. Micronutrient deficiency gradually manifests into diseases, which effects pathophysiology directly or indirectly. There is an imprecision in the diagnosis of micronutrient deficiency because of two causes; the selection of the standard biomarker and the diagnostic technique used. In appropriate diagnosis could increase the severity of the disorder. Instead of a single a combination of biomarkers can give more stringent results for micronutrient testing. Several traditional analytical techniques are used for diagnosis but HPLC, ELISA & LCMS/MS are most sensitive and reliable methods used by CLSIA-certified labs. However, these techniques require well-equipped, centralized laboratory facilities. The diagnostic era moves toward the Point of Care Testing (POCT), a boon in emerging diagnostics, breaking all paradigms of traditional analytical techniques. POCT led us toward the development of biosensors, which encompasses many techniques like paper-based sensors, microfluidic chip, wearable devices, and smartphone-assisted diagnostics, which become more popular diagnostic tools. This outlook summarizes the micronutrients like vitamins A, B5, B6, B7, B9, B12 C, D, and E and Minerals like iron, calcium, zinc, magnesium, and sodium; along with its biomarkers, analytical techniques, and point of care innovation in micronutrients.

A novel biosensor for detecting vitamin C in milk powder based on Hg2+-mediated DNA structural changes

Background:

Detection of Vitamin C (Vc) is very important to protect human health. A lot of methods have been developed for the detection of Vc. However, many methods require complex material preparation and skilled operators. Thus, a simple, label-free biosensor is still urgently needed.

Methods:

In this work, N-methylmesoporphyrin IX (NMM)/G-quadruplex pair was used as a label-free signal reporter. Without Vc, the G-quadruplex DNA and its incomplete complementary chain could form duplex structure by T-Hg(II)-T mismatch. In this case, the G-quadruplex structure could not be formed. When Vc was added, the Hg2+ was reduced to Hg(0). Then, the G-quadruplex DNA became free and formed G-quadruplex structure to emit fluorescence signal.

Results:

Under optimal conditions, this biosensor showed a good linear response in the range of 0.2 - 4.0 μM and a low limit of detection (19.9 nM). This biosensor also had good selectivity towards Vc. Meanwhile, the satisfactory recovery rates (93.2%-102.8%) suggested that this biosensor had attractive potential for measuring Vc in real samples.

Conclusion:

In this work, a simple label-free fluorescent biosensor for the detection of Vc based on Hg2+-mediated DNA structural changes had been developed. The whole experiment was simple and all reagents were commercialized. The label-free detection was realized by NMM/G-quadruplex as a signal reporter. This biosensor was very sensitive with a low limit of detection. And it had a potential practical application for the Vc detection in milk powder.

A Review on Electrochemical Sensors and Biosensors Used in Assessing Antioxidant Activity

Currently, there is growing interest in screening and quantifying antioxidants from biological samples in the quest for natural and effective antioxidants to combat free radical-related pathological complications. Antioxidants play an important role in human health and provide a defense against many diseases. Due to the valuable dietary role of these compounds, the analysis and determination of their amount in food is of particular importance. In recent years, many attempts have been made to provide simple, fast, and economical analytical approaches for the on-site detection and determination of antioxidant activity in food antioxidants. In this regard, electrochemical sensors and biosensors are considered promising tools for antioxidant research due to their high sensitivity, fast response time, and ease of miniaturization; thus, they are used in a variety of fields, including food analysis, drug screening, and toxicity research. Herein, we review the recent advances in sensors and biosensors for the detection of antioxidants, underlying principles, and emphasizing advantages, along with limitations regarding the ability to discriminate between the specific antioxidant or quantifying total antioxidant content. In this work, both direct and indirect methods for antioxidants detecting with electrochemical sensors and biosensors are analyzed in detail. This review aims to prove how electrochemical sensors and biosensors represent reliable alternatives to conventional methods for antioxidant analysis.