GrowDex - Frequently asked questions

GrowDex components. What does it include? 

Q: What is GrowDex used for? 

A: Applications are related to three-dimensional (3D) cell culture, including e.g. advanced in vitro cell models for drug development and toxicity, disease modelling, regenerative medicine research, and storage and transportation of biological samples. 


 Q: What does GrowDex consist of? 

A: Wood-derived nanofibrillar cellulose and ultra-pure water. There are no animal-derived components in GrowDex. 


 Q: Does GrowDex include ECM proteins? 

A: No. GrowDex is clean and well-defined matrix consisting only of nanofibrillar cellulose and ultra-pure water. 


 Q: GrowDex is completely animal-free. BME matrices have components in them that I would like to have in the culture. Can I add them to GrowDex? 

A: Yes, growth factors and proteins can be added to GrowDex. With GrowDex you have better control of the culture conditions adding what you need when you need it. Thus, you can easily repeat experiments with defined conditions and consistent results. GrowDex-A also enables the functionalization of the hydrogel with any biotinylated molecule. 


Differences between the products 

Q: What are the main differences between different GrowDex products? 

A: GrowDex is native nanofibrillar cellulose, stock concentration is 1.5%. 

 GrowDex-T is anionic, transparent and the stock concentration is 1.0%. 

 GrowDex-A is anionic, transparent and it has avidins on the surface of the cellulose nanofibers, enabling the hydrogel functionalization with biotinylated compounds. Stock concentration is 1.0%. 


How to prepare, handle and store GrowDex? 

Q: Does GrowDex need polymerization? 

A: GrowDex does not need to polymerize. It is delivered in the gel form and remains as a semi-solid hydrogel at all times, in temperatures from 0°C to 121°C. 


Q: How do you handle GrowDex hydrogel, as it is in hydrogel form all the time? 

A: GrowDex is shear-thinning material. It means that GrowDex is a semi-solid and highly viscous hydrogel at rest, but whenever a shear force is applied, it becomes more fluid temporarily. Immediately after the shear-force is stopped, GrowDex is a semi-solid hydrogel again. Shear force is generated e.g. during pipetting or injecting GrowDex. Plese see our ‘Instructions for Use’ -video for handling demonstration. 


Q: Can GrowDex be handled with automated dispensing instruments used e.g. high throughput screening applications? 

A: Yes. As GrowDex is shear-thinning and temperature stable material, it can be handled with automated systems in room temperature. This has been demonstrated with variety of different dispensers, such as Biomek NXP, Gyger Certus Flex, Eppendorf EpMotion, Labsystems Echo 525, and ThermoFisher Multidrop. 


Q: Does GrowDex have lot-to-lot variation? How do you control this? 

A: No. Several physicochemical properties, microbiological purity, and standardized cell culture performance assays are analyzed for each lot. This way we can guarantee that cells behave the same way with each lot of product we manufacture. 


Q: How should GrowDex be stored and how long it is stable? 

A: GrowDex and GrowDex-T can be stored at room temperature and have a shelf life of 12 months. Once opened, it is recommended that GrowDex hydrogels are stored in the fridge for a maximum of 3 months to minimize the risk of microbial contamination. The shelf-life of GrowDax-A and GrowDase is 6 months. 


Q: How long is GrowDex stable after dilution? 

A: When GrowDex is diluted with cell culture medium, GrowDex remains stable as long as the cell culture medium.  


Which cell types is GrowDex suitable for? 

Q: What cell types (cell lines, primary cells) can be cultured in GrowDex? 

A: More than 150 different cell types have been cultured in GrowDex. The adjustable stiffness enables the optimization of the culturing conditions for various cells. These include for example: stem cells, liver cells, cancer cells, neuronal cells, epithelial cells, and others. Several application notes and scientific publication are available on our Support Center 


Q: What is the optimal GrowDex concentration and cell seeding density?  

A: The optimal concentration and cell seeding density are dependent on the cell type. We recommend optimizing both for your assays. Please take a look at our application notes and Quickstart guide –video for further information. 


Q: Are cells able to migrate in GrowDex? 

A: Yes. It has been demonstrated using live microscopy that cells, e.g. mesenchymal stem cells and fibroblasts are able to migrate in GrowDex. Nanocellulose fibers in GrowDex are not covalently cross-linked and are able to move.  


How do you analyze the cells in GrowDex? 

Q: Which cell viability assay can be used with GrowDex? 

A: GrowDex allows the free diffusion of chemicals and various viability assays can be used. The following viability assays have been successfully performed for the cells cultured in GrowDex: CellTiterGlo, RealTimeGlo, AlamarBlue, PrestoBlue, LDH, LIVE/DEADWST, MTT, XTT. 


Q: Can the cells be stained and imaged in GrowDex? 

A: Yes. Different microscopy techniques, such as light microscopy, fluorescence microscopy and confocal microscopy have been successfully used with GrowDex. GrowDex is not auto-fluorescent, and antibody stains diffuse through GrowDex. 


Q: How can cells be harvested from GrowDex for e.g. FACS analysis? 

A: Cells can be liberated using GrowDase™ cellulase enzyme. GrowDase degrades nanocellulose fibers to soluble glucose and the gel structure breaks down for easy and gently for cell recovery. As neither human or animal cells contain cellulose GrowDase does not affect them, and the grown cell structures can be retained.