Advances in electrochemical and optical sensing techniques for vitamins detection: a review

Recent Advances in Dietary Sources, Health Benefits, Emerging Encapsulation Methods, Food Fortification, and New Sensor-Based Monitoring of Vitamin B12: A Critical Review

In this overview, the latest achievements in dietary origins, absorption mechanism, bioavailability assay, health advantages, cutting-edge encapsulation techniques, fortification approaches, and innovative highly sensitive sensor-based detection methods of vitamin B12 (VB12) were addressed. The cobalt-centered vitamin B is mainly found in animal products, posing challenges for strict vegetarians and vegans. Its bioavailability is highly influenced by intrinsic factor, absorption in the ileum, and liver reabsorption. VB12 mainly contributes to blood cell synthesis, cognitive function, and cardiovascular health, and potentially reduces anemia and optic neuropathy. Microencapsulation techniques improve the stability and controlled release of VB12. Co-microencapsulation of VB12 with other vitamins and bioactive compounds enhances bioavailability and controlled release, providing versatile initiatives for improving bio-functionality. Nanotechnology, including nanovesicles, nanoemulsions, and nanoparticles can enhance the delivery, stability, and bioavailability of VB12 in diverse applications, ranging from antimicrobial agents to skincare and oral insulin delivery. Staple food fortification with encapsulated and free VB12 emerges as a prominent strategy to combat deficiency and promote nutritional value. Biosensing technologies, such as electrochemical and optical biosensors, offer rapid, portable, and sensitive VB12 assessment. Carbon dot-based fluorescent nanosensors, nanocluster-based fluorescent probes, and electrochemical sensors show promise for precise detection, especially in pharmaceutical and biomedical applications.

Different Aspects of the Voltammetric Detection of Vitamins: A Review

Vitamins comprise a group of organic chemical compounds that contribute significantly to the normal functioning of living organisms. Although they are biosynthesized in living organisms, some are also obtained from the diet to meet the needs of organisms, which is why they are characterized as essential chemical compounds. The lack, or low concentrations, of vitamins in the human body causes the development of metabolic dysfunctions, and for this reason their daily intake with food or as supplements, as well as the control of their levels, are necessary. The determination of vitamins is mainly accomplished by using analytical methods, such as chromatographic, spectroscopic, and spectrometric methods, while studies are carried out to develop new and faster methodologies and techniques for their analysis such as electroanalytical methods, the most common of which are voltammetry methods. In this work, a study is reported that was carried out on the determination of vitamins using both electroanalytical techniques, the common significant of which is the voltammetry technique that has been developed in recent years. Specifically, the present review presents a detailed bibliographic survey including, but not limited to, both electrode surfaces that have been modified with nanomaterials and serve as (bio)sensors as well as electrochemical detectors applied in the determination of vitamins.

Synthesis, characterization, and applications of gold nanoparticles in development of plasmonic optical fiber-based sensors

Gold nanoparticles (Au-NPs) are readily used nanoparticles which finds applications in fields like biosensors, drug delivery, optical bioimaging and many state of art systems used for detection. In the recent years fiber optic sensors have seen utilization of Au-NPs along with other nanoparticles for implementation of sensors for sensing various biomolecules like cholesterol, glucose, and uric acid. The cancer cells, creatinine and bacteria can also be detected with the fiber optic sensors. Given the significance of Au-NPs in fiber optic sensors, the current work is a review of the synthesis, the common methods used for characterization, and the applications of Au-NPs. It is important to discuss and analyse the work reported in the literature to understand the trend and gaps in developing plasmonic optical fiber sensors.

Ascorbic Acid Sensor Based on CdS QDs@PDA Fluorescence Resonance Energy Transfer

An ascorbic acid (AA) sensor was constructed based on the fluorescence resonance energy transfer (FRET) between CdS quantum dots (CdS QDs) and polydopamine (PDA) to detect trace AA sensitively. FRET occurred due to the broad absorption spectrum of PDA completely overlapped with the narrow emission spectrum of CdS QDs. The fluorescence of CdS QDs was quenched and in the "off" state. When AA was present, the conversion of DA to PDA was hindered and the FRET disappeared, resulting in the fluorescence of CdS QDs in an "on" state. Importantly, the degree of fluorescence recovery of CdS QDs displayed a desirable linear correlation with the concentration of AA in the range of 5.0-100.0 μmol/L, the linear equation is y=0.0119cAA+0.3113, and the detection limit is 1.16 μmol/L (S/N = 3, n = 9). There was almost no interference with common amino acid, glucose and biological sulfhydryl small molecules to AA. Trace amount of AA in vitamin C tablets were determined and satisfactory results were obtained; the recoveries were observed to be 98.01-100.7%.