Autofluorophores

Autofluorophores are naturally occurring fluorescent molecules found within biological tissues and cells. Unlike exogenously introduced fluorescent labels, autofluorophores are inherent to the biological system itself, meaning they do not require external application for their fluorescent properties to be observed. These molecules can arise from various cellular components, including amino acids like tryptophan and tyrosine, enzymes, coenzymes such as NAD(P)H and flavins, and even accumulated metabolic byproducts.

The fluorescence emitted by autofluorophores typically occurs within the visible and near-infrared spectrum. Their spectral characteristics, such as excitation and emission wavelengths, are generally broader and less defined compared to synthetic fluorophores. This broad emission can sometimes lead to spectral overlap with intended fluorescent probes, posing a challenge for researchers.

The presence and intensity of autofluorescence can vary significantly depending on the cell type, tissue state, and experimental conditions, such as fixation methods and illumination intensity. Factors like oxidative stress and aging can also influence autofluorophore levels. While autofluorescence can interfere with fluorescence microscopy techniques, its inherent presence can also be exploited. For instance, it can serve as a label-free contrast mechanism in certain imaging applications or provide information about the metabolic state of cells and tissues. Understanding and managing autofluorescence is crucial for accurate interpretation of fluorescence-based biological experiments.