Fluorescent and Colorimetric Sensing of Amino Acids

Fluorescent and colourimetric sensors for amino acids have evolved as critical tools for the selective identification and quantification of proteinogenic and non-proteinogenic amino acids in complex matrices. By translating molecular recognition events into optical signals, these probes exploit mechanisms such as photoinduced electron transfer, intramolecular charge transfer and energy transfer to achieve high sensitivity and selectivity. Covalent derivatisation strategies and supramolecular host–guest interactions form the basis of many systems, enabling turn-on, turn-off or ratiometric responses. Advances in probe design have delivered platforms that operate across a wide pH range, in aqueous media and within biological specimens, meeting the demand for real-time monitoring in medical diagnostics, environmental analysis and food safety. Recent innovations include novel low-molecular-weight fluorophores, dual-emission constructs and hybrid nanocomposites that improve signal fidelity and reduce background interference, rendering the detection of specific amino acids such as lysine, arginine, glutamate and aspartate increasingly practical across diverse applications.

Research from Nature Portfolio

Recent studies have demonstrated the synthesis of novel safirinium dye derivatives bearing N-hydroxysuccinimide esters with tunable lipophilicity and water solubility. These small-molecule fluorophores exhibit efficient cellular staining capabilities, enabling high-contrast imaging of bacterial strains, mammalian cell lines and human skin tissue. By optimising substituent patterns, researchers achieved selective localisation within subcellular organelles including mitochondria and endoplasmic reticulum, while also highlighting potential for monitoring xenobiotic penetration in the epidermal barrier. The straightforward synthetic routes and low cost of these dyes position them as promising alternatives to existing commercial reagents for fluorescent bioimaging and real-time amino acid sensing in biomedical contexts.

Fluorescent and Colorimetric Sensing of Amino Acids publication trend

The graph below shows the total number of articles in fluorescent and colorimetric sensing of amino acids across all publications each year (not limited to Nature Index journals).

Technical terms

Fluorescence: Emission of light by a molecule following absorption of photons, often used for sensing due to high sensitivity and temporal resolution.

Colourimetric sensor: A probe that produces a visible colour change upon interaction with an analyte, enabling detection by eye or simple spectrophotometry.

Ratiometric sensing: A technique that measures the ratio of emissions at two wavelengths, improving quantification by minimising environmental and instrumental variability.

Förster resonance energy transfer (FRET): A non-radiative energy transfer between two chromophores that depends on their distance, used to signal binding events through emission shifts.

Limit of detection (LOD): The lowest concentration of an analyte that can be reliably distinguished from background noise, a key metric for sensor performance.

References

1. A New Pyrroloquinoline-Derivative-Based Fluorescent Probe for the Selective Detection and Cell Imaging of Lysine. Pharmaceuticals (2022).
2. Construction of N-CDs and Calcein-Based Ratiometric Fluorescent Sensor for Rapid Detection of Arginine and Acetaminophen. Nanomaterials (2022).
3. Pyranopyrazole based Schiff base for rapid colorimetric detection of arginine in aqueous and real samples. RSC Advances (2022).
4. Development of Safirinium dyes for new applications: fluorescent staining of bacteria, human kidney cells, and the horny layer of the epidermis. Scientific Reports (2022).