Key Points
- Researchers have discovered a new method to fuse lipid vesicles (artificial cells) at a neutral pH.
- The method uses a fragment of the diphtheria toxin, known as the T domain, to induce membrane fusion.
- This is a breakthrough because it works without pre-treatment or harsh, acidic conditions.
- Positively charged amino acids in the toxin protein play a crucial role in triggering the fusion process.
Researchers have discovered a new way to fuse tiny “artificial cells” called lipid vesicles at a neutral pH. By using a portion of the diphtheria toxin, the team was able to fuse the vesicles’ membranes without any special pretreatment or harsh conditions. This breakthrough, published in Communications Chemistry, could lead to new applications in lab-on-a-chip technologies, biosensors, and the creation of artificial cell prototypes.
Lipid vesicles are tiny spheres with a membrane, and they are important tools in both medicine and nanotechnology. They can be used to deliver drugs to specific cells or to create larger compartments that mimic the complexity of living cells.
One way to create these larger compartments is to allow smaller vesicles to fuse, a process inspired by nature. However, controlling this fusion process in a lab has always been a major challenge.
Now, a research team led by Prof. Dr. Cornelia Palivan at the University of Basel and Dr. Richard A. Kammerer at the Paul Scherrer Institute has found a solution using the diphtheria toxin.
“A specific part of the diphtheria toxin, known as the T domain, can induce membrane fusion even at neutral pH,” explains Piotr Jasko, the study’s first author. “It is unique because normally this toxin works under acidic conditions in cells.”
The team found that certain positively charged amino acids in the diphtheria protein play a key role. These amino acids bind to the negatively charged vesicle membrane and cause the vesicles to stick to a glass surface. This creates an uneven tension in the membrane, triggering the fusion of the attached vesicles with free-floating ones.
“Targeted membrane fusion at neutral pH is of great interest to us because it can be used for numerous applications,” commented Palivan. “It provides the basis for various lab-on-a-chip technologies, biosensors, and possible use with synthetic analogs of liposomes… to produce more chemically advanced and stable cell mimics.”
