FRET-Based Tools for Detection and Real-Time Quantification of Vitamins and Their Bioimaging

Vitamins play a crucial role in facilitating proper metabolism, cellular development, and functioning of other biomolecules, thereby ensuring the proper operation of various body systems. These essential micronutrients enter the body through food and supplements, thus it is important to quantify their concentrations in food, medicines, and biological fluids. Various methods are employed to measure the amount of these organic micronutrients, with selectivity, sensitivity, and limit of detection playing essential performance parameters for analytical techniques. To detect and continuously measure essential micronutrients in source samples and living cells for therapeutic purposes, a simple, reliable, sensitive, and non-invasive technique is required. Metabolite sensors detect metabolite changes and report their abundance within biological networks. Among the emerging options, FRET-based biosensors are gaining popularity due to their capability to visualize the spatiotemporal fluctuations in metabolite dynamics within living cells. FRET occurs within a range of 1–10 nm (Forster radius) between a bright donor molecule and an energy acceptor fluorescent molecule. FRET-based sensor requires a protein that exhibits a high affinity and specificity for the target molecule, along with a significant conformational change upon binding. These nanosensors have the capability to detect alterations in vitamin content in experimental samples in real-time.