Fluorescent Markers

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What are Fluorescent markers?

Fluorophores are used to detect the expression of nucleic acids, proteins, and other cellular molecules. These fluorescent markers gain light energy at a specific wavelength and emit it at a longer one.



The process of accepting the energy is called excitation and the process of re-emitting the light is emission. Usually, emission happens a few nanoseconds after excitation and the process is known as fluorescence.



When a fluorophore absorbs light energy, several things happen. First, its electrons go from resting to the maximal energy level. This level is called excited electronic singlet state and the energy needed to reach this state varies from one fluorophore to another.



This state ends rather quickly: typically, between 1 and 10 nanoseconds and then a conformational change takes place, leading to the electrons decreasing to a more stable level, known as the electronic singlet state.



While reaching this state, some absorbed energy is released as heat. After they reach the electronic singlet state, the electrons slowly continue to fall back to the resting state and release the leftover energy as fluorescence.

Should you use a fluorescent marker?

The reason why they are used is to directly mark the target epitope, so it can be measured. Because more than one fluorophore can be excited by the same laser, multiple parameters can be measured simultaneously.