Autofluorescence refers to the natural emission of fluorescence exhibited by certain biological structures or molecules when exposed to light. Unlike fluorescence that results from the application of external fluorophores or dyes, autofluorescence arises intrinsically from endogenous molecules present in tissues or cells.
Key points about autofluorescence:
Endogenous emission: Autofluorescence occurs due to the presence of naturally fluorescent molecules within biological samples, such as cells, tissues, or organs. Common endogenous fluorophores include flavins, collagen, elastin, and certain coenzymes.
Excitation by light: To induce autofluorescence, the biological sample is typically illuminated with light at a specific wavelength. The endogenous fluorophores absorb this light energy and subsequently emit light at longer wavelengths, producing a characteristic fluorescence signal.
Intrinsic contrast: Autofluorescence can provide intrinsic contrast in biological imaging without the need for exogenous labels or dyes. It is often used in various imaging techniques, such as fluorescence microscopy, to visualize and study the structure and composition of tissues.
Challenges and considerations: While autofluorescence can be advantageous for label-free imaging, it can also pose challenges, especially when trying to distinguish it from signals of interest. Background autofluorescence may interfere with the detection of specific fluorophores or may vary between different types of tissues.
Applications: Autofluorescence is utilized in biomedical research and clinical diagnostics. It has applications in areas such as histology, pathology, and imaging of living cells. Understanding and managing autofluorescence are crucial in obtaining accurate and reliable results in fluorescence-based studies.