Researchers have created flower-shaped particles that can effectively deliver drugs to lesions. The particles, which can be tracked and controlled using medical imaging techniques, show promise in treating cancer and cardiovascular disease after successful initial testing in mice.

These flower-like zinc oxide particles are 3 microns in size (color electron microscope image). Image source: DongWookKim/Max Planck Institute for Intelligent SystemsFor years, scientists have been looking for ways to deliver drugs to specific targets in the body. For example, consider delivering anti-cancer drugs directly to tumors, ensuring they only work in that specific area without causing side effects elsewhere in the body. Research is currently underway to identify carrier particles that can be combined with the active ingredients.These particles must meet certain requirements, including the following three points: First, they must be able to absorb as many molecules of the active substance as possible; second, they must be guided through the bloodstream using simple techniques such as ultrasound; and third, their journey through the body must be tracked using non-invasive imaging procedures. This last point is the only way to verify that the drug was successfully delivered.The particles resemble tiny paper flowers or sand roses and assemble together in a self-organizing manner. Image source: Kim et al., AdvancedMaterials2024

Finding a single solution that meets all these requirements has been a challenge. However, a research team led by ETH Zurich has introduced a special class of particles that meets all these criteria. Not only are these particles effective, they look striking under a microscope, like tiny paper flowers or desert roses. They are composed of extremely thin petals that arrange themselves into flowers. These flower grains are one to five microns in diameter, slightly smaller than red blood cells.

Their shape has two major advantages. First, flower particles have a huge surface area compared to the size of the flower. The gaps between the densely packed petals are only a few nanometers wide, like pores. This means they can absorb large amounts of therapeutically active substances. Second, the petals can scatter sound waves or be coated with light-absorbing molecules, making them easily visible through ultrasound or photoacoustic imaging.

A research team led by Daniel Razansky and Metin Sitti reported these findings in a study published in Advanced Materials. Razansky is a dual-appointed professor of biomedical imaging at ETH Zurich and the University of Zurich. Sitti is an expert in microrobotics. He recently served as a professor at ETH Zurich and the Max-Planck Institute for Intelligent Systems in Stuttgart, and later moved to Koç University in Istanbul.

"Previously, researchers have focused on using ultrasound or other acoustic methods to transport tiny bubbles in the blood," said study co-author Paul Wrede, a doctoral student in Lazanski's group. "We have now shown that solid particles can also be guided acoustically." Compared with bubbles, the advantage of flower particles is that they can be loaded with more active ingredient molecules. "

Researchers have shown in petri dish experiments that flower particles can be loaded with anti-cancer drugs. They also injected the particles into the bloodstream of mice. Using focused ultrasound, they were able to keep the particles in a predetermined position within the circulatory system. They managed to do this despite very rapid blood circulation around the particles. Focused ultrasound is a technique that focuses sound waves on a localized location. "In other words, we're not just injecting microparticles and hoping for the best. We're actually controlling them. Researchers hope this technology can one day be used to deliver drugs to tumors or blood clots blocking blood vessels."

Microparticles can be made from a variety of materials and have different coatings, depending on their purpose and the researcher's preferred imaging procedure to control the location of the microparticle. "The basic working principle is based on their shape, not what they are made of," said Wrede. "In the study, the researchers investigated in detail flower particles made of zinc oxide. They also tested particles made of polyimide and composites composed of nickel and organic compounds."

Now, the researchers hope to refine their concept. They plan to conduct more animal trials first, before the technology could benefit patients with cardiovascular disease or cancer.

Compiled from /ScitechDaily