Laser-activated gold nanostars simplify intracellular delivery

The intracellular delivery method involves star-shaped nanoparticle synthesis based on laser irradiation.

Content Dam Bow Online Articles 2019 02 Nanostars Laser

Intracellular delivery systems are of great importance for clinical and laboratory biomedical research. Recognizing this, a team of researchers from the Russian Academy of Sciences (Moscow, Russia) has developed a method for star-shaped nanoparticle synthesis based on laser irradiation. A wide range of customizable conditions provides an opportunity to create comfortable environment for various substances delivery to different types of cells.

In their study, the researchers developed a delivery method that uses gold nanoparticles with sharp spikes. The researchers obtained them by reducing gold ions on spherical embryos of the same metal. After that, the nanostars were deposited in the form of single layers on the plastic surface and covered with cells. Laser irradiation caused electromagnetic waves to travel on the nanoparticle's surface, thus transporting substances into the cell.

Scientists used circular DNA with a gene encoding a fluorescent protein (pGFP) to test the effectiveness of the developed method. They aimed at delivering this molecules into HeLa cells: human cervical cancer lines. This combination of model cells and the delivered object was chosen due to the frequent use of HeLa cells in clinical and biochemical studies, as well as easy testing since cells to which pGFP was delivered are glowing. The efficiency of the developed method for model cells turned out to be more than 95%. Creating cell-friendly conditions led to almost absolute survival (about 92%), while after delivering using the TurboFect chemical agent, about 75% of the cells survived.

Content Dam Bow Online Articles 2019 02 Nanostars Laser

The new intracellular delivery system is shown. (Image credit: Timofey Pylaev et al.)

The researchers' method is simpler and cheaper than traditional commercial systems for the delivery of molecules into the cell. Other advantages include the absence of direct contact of target substances and cells with nanoparticles, which reduces the likelihood of damage to cells and delivered substances. Moreover, the spiked surface of nanostars creates comfortable conditions for cell growth and adhesion (cell attachment to each other and to the surface). This makes the method applicable for delivering a wide range of molecules to different cells.

"We have developed and optimized a new platform for creating pores in cells based on monolayers of gold nanostars using continuous laser radiation. Using this method, it is possible to produce highly efficient intracellular delivery of various substances in delicate conditions. We assume that methods using such nanoparticles can be an alternative to existing technologies of intracellular delivery of biomolecules for use in gene therapy, targeted drug application, obtaining modified cell cultures and other biomedical research," explains Timofey Pylaev, one of the authors of the study from the Russian Academy of Sciences.

Full details of the work appear in the Journal of Biophotonics.

More in Fluorescence