Frequently Asked Questions



How can I order?

For instructions on how to order SAINT products, please follow this link.

What are the shipment and handling charges on an order?

International shipping and handling costs using our standard carriers (UPS, FedEx, DHL) are € 65 (DAP incoterms). Within the Netherlands the shipment and handling charges are € 15. For packages > 1 kg, or for insurance, a surcharge may be invoiced.

For delivery of orders under EXW or FCA incoterms, a handling and packaging fee of € 15 will be invoiced per order.

Do you have distributors located outside of Europe?

No, we deliver our products worldwide from our offices located in Leiden, The Netherlands.

If you are a qualified and established supplier of life science products and interested in becoming a distributor, then please review our partnering opportunities here.

What are the Terms and Conditions?

Our general Terms and Conditions can be found here.



How should SAINT be stored?

All our SAINT reagents are shipped at room temperature as a ready-to-use transfection reagent. Upon arrival it should be stored at 4-7°C (do not freeze). Stability studies showed that SAINT reagents are stable for at least one year after opening.

I stored my SAINT reagent in the freezer. Can I still use it?

Yes! After thawing the SAINT reagent may appear cloudy and more viscous. Before use make sure to vortex thoroughly to get a homogeneous dispersion, or better, sonificate to transparency. Incomplete re-dissolution of the mixture results in a lower working concentration.

Can I use SAINT in the presence of serum?

Yes! Transfection with SAINT is not inhibited in the presence of serum. More information can be found in these articles from Audouy (2000) and Zuhorn (2002). However, since siRNA are extremely susceptible to degradation by RNAses present in serum, an Alternative Serum-Free siRNA Transfection Protocol using SAINT-sRNA is available.

Will antibiotics interfere with my transfection?

No! Antibiotics have no effect on the transfection efficiency.

Which parameters can influence the transfection results?

In general the following parameters affect transfection results:

  • Purity and concentration of DNA, RNA, oligo’s or proteins
  • Vector sequence (promoter, poly(A)-tail, codon usage, etc.)
  • Amount of SAINT/DNA complex added
  • Target cell (cell type, cell cycle, passage number, etc.)
  • Protein expression (time-dependent expression levels, toxicity of expressed protein, etc.)

Like most other transfection agents and delivery systems, the best results are obtained with highly purified DNA, RNA, or proteins/peptides.

The ‘transfectability’ of cells is highly variable. For example, non-dividing and non-adherent cells are generally difficult to transfect, while other cell types may be transfected readily with efficiencies between 80 and 100%. Also, some transfections reagents may work better on certain cells than others, while some reagents can be toxic to specific cell types. For this reason, we recommend to spend some time on optimisation of the transfection conditions for a particular cell type with a reporter construct such as GFP.

Why doesn’t my transfection efficiency double when I use the double amount of SAINT?

The charge ratio between the cationic component in SAINT-DNA/sRNA/mRNA and the negatively charged DNA/siRNA/mRNA is important for efficient transfection. As a starting point, we recommend 1:20  ratio DNA/RNA:SAINT reagent (w:v) (e.g. for 12 wells format, 0.5 ug DNA:10 ul SAINT-DNA). To achieve optimal transfection results for your experiments, it is worthwile to optimize DNA/RNA dose (e.g.  for 12 wells format, 0.25 ug – 1 ug DNA) and DNA/RNA:SAINT reagent ratio (e.g. for 12 wells format, 1:10 – 1:40).

Which SAINT reagent should I use for co-transfection of DNA, RNA and/or protein?

Our SAINT reagents are optimized for transfection of either DNA (SAINT-DNA), siRNA (SAINT-sRNA), mRNA (SAINT-mRNA) and protein (SAINT-protein), however they can all – to some extend – deliver the other molecules. Depending on the requirements of your experiments you can use one SAINT reagent for two different molecules or use the specific SAINT reagents per molecule.

DNA transfection

What is the DNA size range that can be transfected efficiently with SAINT- DNA?

The smallest size is roughly that of an oligonucleotide (20 nucleotides). The largest size tested in our hands is 20.3 Kb, while others have also succeeded in transfecting BAC constructs > 100kb using SAINT-Mix. In general, smaller plasmids (3-5kb) are transfected more efficiently than large plasmids (6-12kb). Also the configuration of the construct determines the transfection efficiency. Transient transfection is most efficient with supercoiled plasmid DNA, while in stable transfection, linear DNA results in lower DNA uptake by the cells, relative to supercoiled DNA, but yields optimal integration of DNA into the host genome.

My fibroblasts seem to suffer a lot from the transfection protocol, what can I do?

We have noticed that fibroblasts, and also other sensitive cell lines, show better transfection efficiency if the amount of DNA is lowered 2-fold or even 4-fold. The amount of SAINT reagent added needs to be adjusted proportionally to keep the SAINT/DNA ratio constant.

RNA transfection

What is the RNA size range that can be transfected efficiently with SAINT-sRNA and SAINT-mRNA?

SAINT-sRNA was developed for the transfection of small RNA’s, up to 200 nucleotides in length (e.g. siRNA), and SAINT-mRNA for larger RNA molecules.

Protein transfection

What size of peptide/protein can be transfected efficiently with SAINT-Protein?

We have observed efficient SAINT-mediated transfection with peptides larger than approximately 20 amino acids.

Custom services

How do I request a custom order?

For custom products and services, large order volumes, or other inquiries please contact us to discuss your needs and wishes.

Other questions