Circulating Tumor Cells (CTCs)

Deciphering CTC Heterogeneity at Single Cell Level

Circulating tumor cells (CTCs) are cells that have been shed from a tumor and entered the blood circulation. Following adaptation and colonization of the microenvironment of a secondary site they form metastases which are responsible for over 90% of tumor-related deaths. CTCs, obtained through a simple blood draw, can serve as a “liquid biopsy” to monitor tumor characteristics in real-time, including inter- and intra-tumor heterogeneity. However, CTC isolation and subsequent characterization are technically challenging due to the low CTC cell numbers among an abundance of white and red blood cells. A wide range of analytical methods for CTC detection, enrichment and isolation has been developed. They exploit CTC-specific properties such as surface marker expression or e.g., size, density or deformability.

Sartorius offers a unique and complete solution for detection and isolation of CTCs after enrichment and staining steps. Cells isolated can then be used for DNA, RNA or proteome analysis. This solution is centered around the CellCelector system utilizing specifically developed consumables (e. g. CellCelector Nanowell arrays, MagnetPick slides) and validated protocols. 

Single cell CTC isolation and analysis workflow using the CellCelector

The CellCelector used within a typical CTC isolation and analysis workflow. * Red blood cell (RBC) lysis is optional and depends on the used enrichment technology; **Certain enrichment technologies allow in-situ staining after enrichment; in other cases, the staining should be done after retrieving the sample from the enrichment device.

Full compatibility with existing enrichment technologies

As demonstrated in numerous publications the CellCelector platform is compatible with a variety of upstream enrichment technologies:

Positive immuno-magnetic enrichment (based on EpCAM surface markers and others): e.g., CellSearch®, Isoflux™, MagSweeper™

Negative depletion of white blood cells (WBCs) based on CD45 surface markers: e.g., Dynabeads™, RosetteSep™

Label-free separation based on microfluidics or filters: e.g., Parsortix™, Clearbridge™, Vortex™, ScreenCell™, RareCells™, Circulogix™ etc.

The CellCelector workflows and consumables allow handling of up to several hundred thousand of blood cells per sample without the need for sample volume reduction.

Enrichment Technologies


Positive Immuno Magnetic

CellSearch® (EpCAM)

Neumann et al., 2016

Isoflux™ (EpCAM)

Ma et al., 2016; Cabezas-Camarero et al., 2019; Nimir et al., 2019; Ding et al., 2019

MagSweeper™ (EpCAM)

Lohr et al., 2014

Dynabeads and hand-held magnet (rVAR2)

Agerbæk et al., 2018; Bang-Christensen et al., 2019

CD45 Negative Depletion

Dynabeads® CD45/Dynal® MPC®-S

Blassl et al., 2016

RosetteSep™ Human CD45

Yao et al., 2014

Size-based Separation


Lampignano et al., 2017; Szczerba et al., 2019; Gkountela et al., 2019; Reinhardt et al., 2019; Donato et al., 2019

Density Gradient Centrifugation


Heidary et al., 2014

CTC enrichment technologies used prior to the CellCelector single cell isolation and corresponding published papers (full article references can be found on the Publications page).

CTC Isolation from Various Cancer Types

Cancer Type



Heidary et al., 2014; Schneck et al., 2015; Neumann et al., 2016; Lampignano et al., 2017; Szczerba et al., 2019; Gkountela et al., 2019; Reinhardt et al., 2019; Sprouse et al., 2019


Lohr et al., 2014; Ma et al., 2016; Nimir et al., 2019


Adalsteinsson et al., 2013; Cabezas-Camarero et al., 2019


Kim et al., 2019


Blassl et al., 2016


Yao et al., 2014; Ding et al., 2019


Agerbæk et al., 2018; Bang-Christensen et al., 2019


Sprouse et al., 2019

The CellCelector technology is capable to isolate pure single tumor cells from liquid biopsies of any cancer type. Leading cancer centers throughout the world using the CellCelector system are working on developments in numerous cancer entities and application areas.

Benefits of CellCelector Platform for CTC Isolation


  • Very low cell loss (no dead volume)
  • Single cell picking efficiency up to 100 % (depending on workflow)
  • Automated picking control (Picked/Failed)


  • 20 individual single CTCs picked within just 10 minutes making the CellCelector compatible with RNA analysis and live cell picking
  • Process for enumeration and isolation of CTCs takes around 1 hour per sample (starting from an enriched and stained sample)

Easy to Use

  • No complex sample preparation necessary
  • User-friendly yet powerful software

Highly Versatile

  • Isolation of individual single CTCs and clusters
  • Isolation of fixed and live cells
  • Direct compatibility with various upstream enrichment methods
  • Automated CTC detection based on cell morphology, pathological stains and/or up to 6 fluorescence labels
  • Automated, semi-automated or manual cell selection for picking
  • Picking of either individual cells or cell pools
  • Compatible with most labware: well plates, Petri dishes, microscope slides, PCR plates/tubes, nanowell arrays, custom consumables etc.

Fully Compatible with Various Downstream Analysis and Cultivation Workflows

  • Compatibility with a wide range of single cell molecular analysis methods including NGS, RNAseq, etc.
  • Low aspiration and dispensing volumes for seamless compatibility with all single cell WGA and qRT-PCR kits

  • Temperature controlled destination positions (4 to 37 °C) for preventing RNA degradation or facilitate live cell survival
  • Low shear stress and fast picking enabling live cell expansion

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