Spheroid Model & 3D context:
Frequently Asked Questions
- What is 4DCell?
4Dcell is a biotech company which provides solutions for cellular microenvironment control.Innovation in cell culture methods requires new tools to control the cell microenvironment, like microfluidics and micropatterning. Developing and spreading these technologies for research laboratories and industry is our ambition.
- Can I get samples to test your system in my lab conditions?
In order for you to first try the 4Dcell products, we provide affordable starter packs (with either 20 or 50 articles). Therefore, you can have a first impression and confirm your experimental needs before ordering the appropriate products.
- How do I order and pay?
When you have decided which products you want to order, you can send us an order form. We will send you an invoice so that you can pay by bank transfer or with a Paypal account.If you have a special request concerning the payment method, contact us and we will find an appropriate solution.
- What is the delivery time?
We send the products in a delay of one month from the day we receive the order form.
- What are micropatterns and how can I use them?
Micropatterns allow you to control the shape of your cells and have single cell imaging. You can choose between several shapes and sizes, depending on the cell type and on your experimental needs. 4Dcell provides various micropatterned products. Discover them on the Micropatterns page.
- What is the standard 4Dcell photomask?
Our mask is 2.5 inches, and allows to microprint 4 coverslips (24-25mm diameter) at the same time. Our standard designs are made of 8 areas, with approximately 42 sub-areas fully observable with a 10x objective field. For one slide you have thousands of printed micropatterns. Sizes of the patterns go from 10 to 100 µm. You can see all the features of the standard 4Dcell photomask page.
- Is it possible to design my own micropatterns?
Yes, it is possible. You can order a customized photomask with the features you want. Either you already have the design of the customized photomask and you can directly send it to us (in GDS, DXF, EPS or PDF format) or you can precisely describe what you want and we will take care of the customisation.
- Is it possible to pattern 18 or 22mm slides?
Yes, the patterns are organized in such way that you can get all the micropatterns sizes no matter the size of your slides.
- What is the lab equipment needed to make micropatterns?
To make micropatterns, 4Dcell provides a micropatterning station with the equipment needed. Basic laboratory materials is then mandatory to perform the experiment such as tweezers or micropipettes. Working in a clean environment is necessary to have good results.
- How stable are the generated micropatterns in presence of cell culture conditions, in aqueous solution?
The stability of the micropatterns in presence of cells depends on the cell type. Typically, standard PEG treatment used in the 4Dcell micropatterns fabrication kit lasts about 24h. 4Dcell precoated slides and pre-patterned slides use improved anti-adhesive polymer treatments which are more stable (several days of culture). The most stable treatment allows up to weeks of culture in certain conditions. Before usage and stored at room temperature, precoated or prepatterned consumables are stable for months.
- How efficient is the coating process when using your system – will there likely be patches that do not coat properly? and if so, at what frequency do you typically see this?
The quality of the micropatterns depends on the precautions taken during the experiment. We also provide already coated slides ready to be printed with micropatterns. The coating is of very high quality and you can choose from 3 different molecules.You can have a look at the webpage of the pre-coated slides.
- I do not use fibronectin, is it possible to replace it? Do you provide alternative matrix solutions for coating – collagen for instance?
Yes, it is possible to use a different matrix from fibronectin. We can adjust the content of the kit for you. Contact us so that we can find a solution which fits your needs.
- How many times can I use the micropatterns photomask?
In proper conditions, the photomask can be used lots of times. The most important is to handle it gently during the experiment and to avoid scratches on it.
- Are the slides sterile once coated?
The solutions used at 4Dcell are all sterile so if you manipulate in sterile conditions, the slides will remain sterile too.
- Is it possible to pattern something else than eukaryotic cells?
Yes, you can micropattern other biological objects but you have to adapt the matrix for this specific object (bacteria, for instance).
- I am wondering about the size of the micropatterned dish, does it have the standard optimal size for confocal imaging or does it need some specific tool?
The micropatterned dishes are of standard size (35mm diameter, 11mm height), with a glass bottom (between 0.13mm and 0.17mm thickness), adapted to most high magnification objectives of confocal and fluorescence inverted microscopes.We also offer pre-coated and micropatterned slides which you can adapt to your imaging system.
- What are microchannels and how can I use them?
Microchannels are microscopic channels engraved into PDMS chips. They allow you to study cell migration within microchannels of different shapes and sizes. You can adapt the features of the system depending on what conditions you want to impose to your cells.
- What is the procedure to make the chip?
The experimental procedure is detailed on the website, with a microchannels tutorial and a user guide explaining all the steps.
- What are the technical parameters of your microchannels?
All the features of the standard microchannels are detailed on the website.Along with the standard features, you can ask for customized microchannels. Contact us and we will discuss your needs.
- Are the microchannels open or are they more like tubing?
The microchannels are closed, after molding, the chip has to be attached to a glass bottom petri dish to close the system.
- Which material are you using?
The elastomer used a standard bi-composant PDMS Sylgard 184, mixed at a weight ratio of 10:1 with the curing agent.
- How many times can I use the molds?
The molds can be used various times if handled gently and kept in proper clean conditions. In the microchannels kit, 4 molds are provided to allow you to make more than 100 chips.
- In your video, how did you achieve the slow flow? I assume the video is in real-time.
On the website video, there was no induced flow into the microchannels, this was spontaneous migration. It was a live-imaging video, and speed has been accelerated to obtain this result. (0.5 img/min)
- Is it possible to induce a flow rate in your microchannels, with a perfusion system?
Yes it is possible, you can control the flow rate thanks to the perfusion pack which has a flow controller, with a range going from 10nL/min to 5mL/min.
- How can I clean the molds?
The molds are quite fragile, they have to be handled gently. The best way to clean the molds is to mold PDMS in them and carefully remove the chip to remove any excess dust or PDMS residues. The molds are not chemically resistant, do not use solvents.
- What lab equipment do I need to make microchannels chips?
To make microchannels in your lab, you need to use a plasma cleaner to activate the surfaces before bonding. We also recommend the use of an oven (up to 80°C) and a desiccator but it is not necessary.
- What is the cell confiner?
- The Cell Confiner reproduces the conditions cells are normally living in the body: they are confined. It allows you to control the thickness of your cells and the volume of the cell culture. By a non-destructive method, you can precisely define the volume of the culture, and specific pressure applied upon cells. This constitutes a new and relevant system to culture cells triggering biomimetism.
- How can I use it?
The confiner is compatible with standard plates (such as petridish/fluorodish, or 6-well plates). It is also compatible with high-resolution live imaging, and standard biological assays.
- What are the differences between the dynamic and the static confiner?
The static confiner offers the possibility to observe the effect of confinement on your cells, in a static state, and compare it to the « normal » cell state.
The dynamic confiner is suited for varying the confinement on the cells, in a dynamic way, confining and retrieving or even varying the strength.
- How many times can the device be used?
The Cell Confiner can be used multiple times, depending on the use and handling. To keep them longer, be sure to handle them gently and clean them properly at each usage with 70% ethanol.
Each system includes, what needs to be changed, for you to replace some parts at least once if needed. We also provide additional consumables on demand.
- How it is possible to control the height of the culture?
The height of the culture can be controlled thanks to micro pillars systems anchored on a glass slide, which are pushed/pulled by a suction cup. The height of the pillars can be adjusted from 3 µm to 20 µm.
- What are hydrogels and how can I use them?
The hydrogels are lyophilized peptide gels which mimic the behaviour of the body’s tissues and organs. You can control the stiffness and biologically functionalize the gel. The 4Dcell hydrogels allow you to do 2D and 3D cell culture.
- What is the procedure to make the gels?
The experimental procedure is detailed on the website, with hydrogels turorial and a user guide explaining all the steps.
- Can the powder be used several times (and so opened several times and defrosted)?
Yes, the product can be used several times. We advise weighing out the required volumes for the experiment, and then any unused powder can be sealed and placed back in the freezer for future use.
- Does the cell media volume have an impact on the gel features such as stiffness?
The cations within the media cause the peptide fibers to cross link and form a gel. Before this addition, the gel is not formed yet (only a pre-gel solution).
Higher volumes of media should not have an effect on gel stiffness as long as the gel surface is covered by the media. Excess media is required only to provide cells with the needed nutrients.
- In the gel forming process: how much time do we have to wait after rehydrating with water, before adding cell culture media?
After the powder is rehydrated, a pre-gel solution is formed. This solution can be plated immediately in the chosen format and cell media added then to set the gel into its final stiffness.
- What is the size of the pores’ fibers?
The fibers themselves do not have pores. The peptide building blocks will form fibers when a crosslinking agent is added (e.g. calcium cations). Then the fibers crosslink and can form spaces/pores in between them. There is no definitive pore size as this will vary depending on the gel concentration. A higher gel concentration will induce dense fiber gels and smaller spaces.
- Are the proteins (fibronectin, laminin or other proteins) already in the initial powder or do they have to be added during the process? If so, at which step? Are there any well known cross linked reactions?
The proteins are already in the initial powder and should be handled in the same way as the standard powder. We have looked at incorporating proteins at a later stage but found that the resulted gels were more unstable and weaker over time.
- What are the different types of use between the 2 laminin peptides?
YIGSR is from the laminin beta-1 chain and promotes cell attachment, spreading and migration.
IKVAV is from the laminin alpha-1 chain and helps with cell adhesion and neurite outgrowth.
- To remove bubbles from the gel, is it possible to use a dessicator?
To remove bubbles, we advise using a sonicator or centrifuge to allow the bubbles to rise to the top of the pre-gel solution before plating. Also leaving the pre-gel solution over a period of time generally reduces/removes the bubbles (i.e. overnight).
- Is it possible to control precisely the volume?
The volume of pre-gel added is controlled by using a pipette.
- How and when do you insert cells in the spheroids?
The cells are added to the pre-gel solution and mixed well before the sphere is formed in the media.
- Do the cells enter the spheroids or just stay at the surface?
Sphere format can only be used for 3D cell culture as the cells will be dispersed throughout the gel.
- Do the trypsin residues included with the cells have an impact on the gel structure/stiffness?
We have not found trypsin to have an effect on the gel structure.