---
title: "How should I deal with debris after cell/nuclei isolation?"
slug: "how-should-i-deal-with-debris-after-cell-nuclei-isolation"
tags: ["cut and tag", "cut and run", "dna methylation", "fiber-seq", "sample prep"]
updated: 2026-09-02T02:06:58Z
published: 2026-09-02T02:06:58Z
canonical: "support.epicypher.com/how-should-i-deal-with-debris-after-cell-nuclei-isolation"
---

> ## Documentation Index
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> Use this file to discover all available pages before exploring further.

# How should I deal with debris after cell/nuclei isolation?

Debris in your sample prep can mean different things based on its source. Below are brief overviews of how debris should be treated based on the sample type you are working with.

## Fresh cells

When using freshly harvested cells as input into your CUT&RUN assay, it’s important to avoid producing debris in your sample prep as much as possible. Debris in a native or lightly fixed single cell suspension is a sign that your cells have become stressed during processing, leading to cell lysis and the leakage of cytoplasmic and nucleic acid components into the supernatant. This can be common when working with fragile primary cells or stem cells, but may also be a result of rough handling or overly harsh dissociation conditions.

If you observe debris in your fresh cell prep you should consider modifying your handling procedures. Recommendations include:

- Reduce the shear stress experienced by the cells by pipetting more gently and/or using wide bore tips or serological pipettes rather than micropipettes.
- Modify your cell detachment protocol, either by reducing the time your cells are exposed to 0.05% trypsin or by considering a more gentle dissociation reagent, such as Accutase, TrypLE, or PBS supplemented with 0.5mM EDTA for highly sensitive cells (such as iPSCs).
- PBS supplemented with 0.5mM EDTA can also be used to wash cells before applying your cell detachment reagent, as the chelating effect of EDTA removes the calcium that allows adherent junctions to hold cells together.

## Cryopreserved cells

Similar to fresh sample preparations, cryopreserved cells (from culture or primary sources) should have minimal debris. Another factor to consider with this sample type is whether the cells were cryopreserved correctly, using an appropriate cryo-protectant (such as 10% DMSO) and freezing at a controlled rate (decreasing the temperature by approximately 1 degree Celsius per minute). This can be achieved by using a slow-cooling method such as a CoolCell or Mr. Frosty system with isopropanol. When working with primary cells, such as PBMCs, it is also important to consider whether a red blood cell removal step is necessary to minimize debris in your work-flow.

## Sample type: Nuclei derived from cell suspension

Debris present in nuclei preparations is either leftover cytoplasmic fragments from cellular lysis, or from lysing of the nuclei themselves. For most cell types, cytoplasmic debris should be easily removed during the centrifugation and resuspension steps. If this is not the case, it is possible to add an additional wash step to further remove any contaminants. If the debris is resulting from nuclei lysis, this can be addressed by reducing the time your nuclei are exposed to the hypotonic nuclei extraction buffer. This lysis is more likely to occur with fragile primary cells or immune cells with a low cytoplasmic content. Significant nuclei clumping can be a sign that there is nuclei lysis in your sample and too much sticky genomic DNA is being released into the supernatant.

## Sample type: Nuclei derived from frozen tissue

For dissociation of snap frozen tissue (prepared through exposure to liquid nitrogen or dry ice), the presence of debris after nuclei dissociation is expected, as it derives from the extracellular matrix (ECM) and cytoplasmic material that surrounds the nuclei. This type of debris can have a negative impact on the signal-to-noise ratio in your data, but the need to remove debris should be weighed against the expected loss of nuclei yield. The signal strength of your target antibody will also impact upon the resulting data.

![](https://cdn.document360.io/1fc69f91-cf1e-45ab-bc51-4063eb80e37c/Images/Documentation/image-1786417109445.png)

  

**Figure 1.** Comparison of cells and nuclei with low and high levels of debris. All samples were stained with AOPI. The left-hand panels are examples of good quality samples, while the right-hand panels are examples of poor quality samples that would require further optimization prior to usage in CUTANATM assays.