Sequential acquisition separates channels temporally rather than spectrally. Modes include frame-sequential (change excitation between frames) and line-sequential (change excitation between scan lines). Time overhead depends on switching speed and whether Z-stacks require re-acquisition per channel. Modern systems minimize overhead with fast filter wheels, AOTFs, or multi-line lasers.
Acquisition Strategy
Sequential Acquisition
One channel at a time to avoid bleedthrough
View
Definition
Imaging each fluorescence channel in sequence rather than simultaneously, eliminating spectral bleedthrough at the cost of additional time for separate exposures. Essential when emission spectra overlap significantly.
Technical Details
Simplified
Instead of trying to separate mixed colors after the fact, sequential acquisition takes pictures with one color at a time. It's slower but guarantees no color mixing. Like taking separate photos with different color filters rather than trying to split mixed light.
Why It Matters
For fluorophores with overlapping spectra (like DAPI bleedthrough into green channels), sequential acquisition may be the only way to get clean channel separation. The time cost is usually acceptable for eliminating crosstalk artifacts.
Practical Example
DAPI strongly overlaps with blue-excited channels. Solution: acquire DAPI first with 405nm excitation only, then switch to 4-channel simultaneous acquisition (488/561/594/647nm). The overhead of one dichroic switch is negligible compared to eliminating DAPI bleedthrough.