
How Do Cloudz™ Cell Activation Kits Work?
The Sky Is The Limit
Cloudz is a customizable cell activation and expansion platform that reduces the complexity of cell processing. Cloudz microspheres are dissolvable, eliminating the extra handling steps for clearing the reagent from your cultures.
What are Cloudz Reagents?
Cloudz reagents are microspheres composed of an alginate-based hydrogel. The microspheres are available in multiple sizes and can be functionalized with a variety of ligands including antibodies and proteins. Derivatized Cloudz reagents present solid phase bound ligands to cells to amplify receptor crosslinking and intracellular signaling.
The alginate hydrogel quickly dissolves when exposed to the release buffer, allowing for gentle and efficient removal of the microspheres. This dissolving property also allows you to precisely terminate the Cloudz ligand signaling to your cells and reduces processing steps.
Cloudz Expansion Protocol – A Simple 3-step Process
- Add Cloudz to your cell culture.
- Incubate cell culture with Cloudz.
- Add release buffer to dissolve Cloudz microspheres.
Expanded cells are ready for use, free of residual particulates.
Customizing Your Cloudz Kit
Fine tune cell activation by modulating the receptors and signal transduction pathways of your choice. The flexibility of the Cloudz platform enables addition of any cytokine or antibody to dissolvable microspheres to optimize a specific cell culture process.

Customize Your Cloudz With Ligand Choice
- Leverage thousands of catalog and non-catalog antibodies and proteins, or bring your own
- Functionalize custom Cloudz with several ligands or several custom Cloudz with a single ligand
- Choose Cloudz sizes from 2-200 µm to match your application
Customize Your Cloudz For Process Development and Analytics
- Readily transition discovery stage custom Cloudz into GMP-grade material for clinical processes
- Receive QC assay support for Cloudz ligand detection, Cloudz size determination, and residuals quantitation
- Combine cell culture evaluation with protocol adaptation for specific culture platforms (e.g. G-Rex® bioreactors, bags, plates)
Screening Cloudz

A Customizable Platform for Tuning Cell Expansion and Activation Protocols
Screening Cloudz enable you to discover the most effective ligands for your particular assay. They’re derivatized with streptavidin which means you have the flexibility to functionalize them with the biotinylated ligand of your choice. The sky is the limit!
Once you have identified your optimum ligands, we can manufacture a Cloudz kit at the scale you need.

Unmatched Flexibility With Screening Cloudz
- Target the cell surface molecules of your choice
- Evaluate multiple antibody clones, protein constructs, or small molecule analogs
- Optimize the number of ligands per microsphere
- Optimize cocktails of Cloudz carrying different ligands
- Evaluate stepwise cell activation by using different beads sequentially
- Target inhibitory receptors with antagonistic ligands
Supporting Reagents and Services
- Avi-Tag biotinylated proteins at R&D Systems
- Biotinylated antibodies
- Custom Conjugation at Novus
- Custom Protein Conjugation & Biotinylation at R&D Systems
- Sulfo-NHS-LC-Biotin for biotinylating your own ligand
- Custom Chemistry Services at R&D Systems
Cloudz Kits for Immune Cell Activation and Expansion
Having a reliable and scalable cell expansion platform is critical for a growing manufacturing process. Cloudz kits are available in RUO and GMP-grade to support consistent and seamless process translations. If you do not see the ligands optimal to your process, contact our Custom Services team to develop a customized kit.
Description |
Expansion Capacity |
Formats |
Ligands |
Optimized For Use With |
> 50-fold expansion of T cells from PBMCs or purified T cells in 10 days |
RUO, GMP |
Fully Humanized CD3 and CD28 Antibodies |
ExCellerate Human T Cell Expansion Media, Recombinant Proteins, GMP Proteins |
|
500-fold expansion of Treg cells from CD4+ T cells in 9 days |
RUO, GMP |
Fully Humanized CD3 and CD28 Antibodies |
ProDots Recombinant Human IL-2 GMP Protein, ExCellerate Human T Cell Expansion Media, Recombinant Proteins, GMP Proteins |
|
>100-fold expansion of NK cells in 10 days |
RUO |
Mouse CD2 and NKp46 Antibodies |
||
Cloudz Human NK Cell Expansion Kit (Coming Soon) |
>100-fold expansion of NK cells in 10 days |
RUO |
Fully Humanized CD2 and NKp46 Antibodies |
Serum-Free and Animal-Free Cell Culture
Increase the consistency of your cell cultures as you approach translational studies for cell therapy and regenerative medicine programs. In cell therapy manufacturing processes, the use of Cloudz complements these media which will
- Reduce variability in media composition
- Simplify compliance with regulatory guidelines
- Simplify comparability testing for raw material changes


Bio-Techne believes in the power of partnerships. We have joined with Fresenius Kabi and Wilson Wolf to bring you ScaleReady for immune cell therapy manufacturing. ScaleReady brings cell and gene therapies to life by streamlining manufacturing processes across cell culture, cell activation and expansion, gene editing, and cell processing.
Cloudz is one of the cell culture technologies available through ScaleReady. The incorporation of Cloudz kits will simplify the cell expansion stage of your manufacturing process.
Learn More at ScaleReady.com

This new eBook provides an overview of several biological and manufacturing challenges facing the development and production of T cell therapies. It follows with examples of how Bio-Techne products and services can address these challenges at each stage of the process.
Are the Cloudz Cell Activation/Expansion Kits cell isolation kits?
No, our Cloudz kits do not isolate cells but are cell activation/expansion products. However, we offer T Cell Enrichment Columns or MagCellectTM Cell Selection Kits for cell isolation.
What is the difference between cell activation & cell expansion?
Exposure of immune cells to the ligands on Cloudz microspheres activates intracellular signaling to promote cell expansion and provide you with a robust cell culture during activation and expansion steps of cell culture.
Why are flasks placed vertically instead of horizontally in the protocol for Cloudz NK Cell Expansion kit?
The vertical positioning is mostly important for the first 3-5 days of culture (depending on donor). It maintains a higher cell density and allows them to survive to proliferate at later timepoints.
Is the expansion rate of cells independent of the source of the cells?
Donor to donor variability plays a significant role in the growth kinetics of cells, and will impact the ultimate expansion and phenotype of your expanded cells.
When should I remove my Cloudz particles from my cells?
The Cloudz microspheres can either be dissolved after 48 hrs, or remain for the entire culture period.
How do I remove Cloudz microspheres from my cell culture when my cells have reached maximal confluency?
The Release Buffer in the Kit can be added to culture to completely dissolve away Cloudz Microspheres. Cells can then be spun down and washed to completely clear the release buffer from culture. Do not leave cells in release buffer for more than 30 minutes.
How do I confirm removal of Cloudz microspheres from my culture?
Cloudz Microspheres can be assessed using Micro-Flow Imaging particle analysis to observe dissolution of the Cloudz.
Should I use serum-free media or serum-containing media for expansion of NK cells in the Cloudz Human NK Cell Expansion Kit?
Expansion of NK Cells in serum-free media is more challenging than expansion in media containing serum. Comparatively, donor to donor variability has a larger impact on NK cell expansion in serum-free media than in serum-containing media.
Cloudz Human T Cell Activation Kit and the Cloudz Human Treg Expansion Kit both contain Cloudz CD3/CD28 antibodies. Can the antibodies provided in the kits be substituted for various cell types and provide the same results?
While both kits have the similar antibodies, each product is manufactured and optimized to each type of cell expansion (T cell or Treg). Use of Cloudz CD3/CD28 from one kit to another is not supported.