SCYM Cell Sorting 5

Question 1

What is the significance of 'satellite droplets' in a droplet-based cell sorter?

Accepted Answer

They are small droplets that can carry cells and contaminate adjacent sort streams

Answer

Satellite droplets are tiny droplets that form alongside the main droplets and can carry cells into adjacent collection streams, potentially contaminating sorted populations.

Question 2

A researcher sorting GFP-expressing cells notices that the sorted GFP-positive fraction contains many GFP-negative cells. Which instrument parameter should be investigated first?

Accepted Answer

Sort delay (drop delay) accuracy

Answer

When gated purity is adequate but sorted purity is low, an incorrect sort delay is the most common cause, as it means the wrong droplet is being charged and deflected.

Question 3

Which aerosol containment strategy is most effective for sorting infectious or BSL-2 human samples on a conventional jet-in-air sorter?

Accepted Answer

Using an enclosed sort chamber with HEPA-filtered exhaust and working under negative pressure

Answer

An enclosed sort chamber with HEPA-filtered exhaust and negative pressure prevents aerosols containing potentially infectious particles from escaping into the operator's environment.

Question 4

What does a high event rate on the sorter primarily increase the risk of, even when sample concentration appears low?

Accepted Answer

Coincident events leading to reduced sort purity

Answer

High event rates increase the probability that two cells arrive at the interrogation point within the same droplet window, causing coincident events that reduce sort purity.

Question 5

When sorting for downstream single-cell RNA sequencing (scRNA-seq), why is it important to minimize the time cells spend at room temperature during sorting?

Accepted Answer

Ex vivo time at room temperature alters transcriptional profiles, introducing artifacts

Answer

Cells rapidly change their gene expression profiles in response to stress and environmental changes, so minimizing pre-sort time at room temperature helps preserve in vivo transcriptional states.

(SCYM) Specialist in Cytometry Practice Test

(SCYM) Specialist in Cytometry Practice Test

SCYM Cell Sorting 5