Protein Transfection Reagents

PULSin® enables you to study lethal proteins by controlling the level and time course of protein delivery into the cells. Similarly, delivery of blocking antibodies may provide additional information to traditional RNA interference experiments*. With PULSin® you can target intracellular proteins with antibodies in living cells without fixation.

* G. Cassinelli et al. (2006). Inhibition of c-Met and prevention of spontaneous metastatic spreading by the 2-indolinone RPI-1, Mol Cancer Ther 5:9, 2388-2397.

  • Effective and robust delivery into the cytoplasm
  • Delivery to a wide variety of cells including primary cells
  • Highly efficient transfer
  • Easy to use

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PULSin: reagent for delivery of functional proteins & antibodies to living cells

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PULSin: reagent for delivery of functional proteins & antibodies to living cells

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Efficient delivery of proteins/antibodies and peptides to the cytoplasm


PULSin® was shown to deliver R-phycoerythrin, a fluorescent protein (240 kD) to the cytoplasm of up to 98% cells. As shown in Figure 1, the protein is evenly distributed in the cytoplasm and excluded from the nucleus due to its large size.



Fig 1. PULSin®-mediated intracellular delivery of R-phycoerythrin to NIH-3T3 cells. R-phycoerythrin (1 µg) was complexed with 4 µl of PULSin® for 15 min and added to NIH-3T3 cells in a 24-well plate. Live cells were observed by fluorescence microscopy after 16 h.



Antibodies were also successfully delivered to HeLa cells and able to recognize their target protein inside the cytoplasm. For example, PULSin® permits the delivery of FITC-labeled anti-alpha-tubulin to the cytoplasm of 85% HeLa cells (Fig.2).

Antibodies (1)



Fig 2. Delivery of a fluorescein-conjugated anti-alpha-tubulin antibody with PULSin® to HeLa cells.




Similarly, anti-giantin Alexa Fluor® 488 was delivered to the cytoplasm of 98% of live HeLa cells, labeling the Golgi apparatus (Fig.3).

Antibodies fig 2



Fig 3. Golgi labeling (green) of  HeLa cells 24 h after delivery of 1 µg Alexa Fluor® 488 anti-Giantin using PULSin®.




Plasma membrane was stained with ConA-rhodamine. Cells were observed by confocal microscopy.


Peptides are biomolecules acting with high specificity at low concentrations. The delivery of substrate, inhibitor, modulator, or blocking peptides into cell allows protein function studies as well as the development of therapeutic approaches. PULSin® was shown to successfully deliver Streptococcus TPE B epitope into HeLa cells (Fig. 4).


Fig 4. Delivery of Pep-A (Streptococcus TPE B epitope, 16 aa), into HeLa cells. Complexes were formed with Pep-A (1 µg, lissamine-rhodamine derivative, Sigma) and PULSin® (4 µl). Observation was carried out 16 h post-delivery.




Other proteins, antibodies and peptides have also been delivered to cells using PULSin™ (Table 1).

Pulsin table








Table 1. Examples of proteins, antibodies and peptides delivered to cells using PULSin® 





PULSin® is easy to use and fast

PULSin® will save you time compared to other techniques using viral transduction or chemical conjugation. PULSin® reagent is ready-to-use and provided with a dilution buffer and a fluorescent control protein (R-phycoerythrin).

  • The protocol is fast: simply add the reagent to the protein, incubate and add to the cells
  • Cells can be analyzed starting 4 hours post-delivery

Delivery to a wide variety of cells

PULSin® was shown to deliver proteins and antibodies to a large variety of cell lines and primary cells (Table 2, Fig. 1-3).

Pulsin table 2






Table 2. Efficiency of R-phycoerythrin delivery using PULSin® in selected cells.





Highly efficient transfer

The comparison of PULSin® with two other protein delivery reagents showed a higher efficiency of protein delivery (Fig. 5). Moreover, the amount of protein delivered per cell was higher with PULSin®as measured for R-phycoerythrin protein and for FITC-alpha-tubulin antibody (Fig. 6).

Pulsin transfer (1)

Fig 5. Comparison of PULSin® efficiency with two other protein delivery reagents. R-phycoerythrin (1 µg) was complexed with each reagent according to the manufacturer’s protocol. Complexes were added to HeLa cells and observed by fluorescence microscopy over 24 hours.

Mechanism of delivery

PULSin® contains a proprietary cationic amphiphile molecule that forms non-covalent complexes with proteins and antibodies.

Complexes are internalized via anionic cell-adhesion receptors and are released into the cytoplasm where they disassemble. The process is non-toxic and delivers functional proteins.

Useful pages

Virus infected/uninfected cell extracts

Viral proteins

Viral test kits



Weiss, A.,  Neuberg, P., Philippot, S., Erbacher, P., and Weill, C. (2011). Intracellular peptide delivery using amphiphilic lipid-based formulations. Biotechnol Bioeng 30.

Weill, C., Biri, S., and Erbacher, P. (2008b). Cationic lipid-mediated intracellular delivery of antibodies into live cells.Biotechniques 44, Pvii-Pxi.7

Weill, C., Biri, S., Adib, A., and Erbacher, P. (2008a). A practical approach for intracellular protein delivery. Cytotechnology 56, 41-48.