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Updated: May 3, 2026

Delivery of Proteins, Peptides or Cell-impermeable Small Molecules into Live Cells by Incubation with the Endosomolytic Reagent dfTAT
Published on: September 2, 2015
Intracellular delivery of functionally active proteins using self-assembling pyridylthiourea-polyethylenimine
Viktoriia Postupalenko1, Annie-Paule Sibler2, Dominique Desplancq2
1LCAMB UMR 7199, CNRS Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, 67401 Illkirch, France.
This study introduces a novel pyridylthiourea-modified polyethylenimine (πPEI) for efficient intracellular protein delivery. The self-assembling πPEI protects and delivers functional proteins, including antibodies, into mammalian cells for research and potential therapeutics.
Area of Science:
- Biotechnology
- Cell Biology
- Polymer Chemistry
Background:
- Intracellular delivery of functional proteins is crucial for research and therapeutics.
- Existing methods for protein delivery face challenges in efficiency and maintaining protein activity.
- Novel delivery systems are needed to overcome these barriers.
Purpose of the Study:
- To characterize a self-assembling pyridylthiourea-modified polyethylenimine (πPEI) for intracellular protein delivery.
- To demonstrate the system's ability to deliver functional proteins, including antibodies, into mammalian cells.
- To explore the therapeutic potential of this delivery system for cellular interference.
Main Methods:
- Synthesis and characterization of pyridylthiourea-modified polyethylenimine (πPEI).
- Formation of supramolecular protein-entrapped assemblies with green fluorescent proteins (GFP).
- Delivery of antibodies against intracellular targets (HPV-16 E6 oncoprotein and EG5 kinesin) into mammalian cells.
Main Results:
- πPEI self-assembles with proteins, protecting their function and facilitating cytosolic delivery via endocytosis.
- Delivered anti-E6 antibodies restored p53 tumor suppression in E6-transformed cells.
- Delivered anti-EG5 antibodies reduced cancer cell viability and disrupted mitosis.
Conclusions:
- πPEI serves as an effective and versatile system for intracellular delivery of functional proteins and antibodies.
- This delivery system enables epitope recognition within living cells and offers potential for selective cell function interference.
- The findings open new avenues for antibody-based research and therapeutic strategies targeting intracellular components.
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