For nanoparticles, shape is of great importance

Joseph DeSimone, a professor at the University of North Carolina at Chapel Hill and the University of North Carolina (Raleigh), tested the ability of nanoparticles shaped like cubes and short and long cylinders to be absorbed by human cells in culture. It turned out that elongated b nanoparticles penetrate into cells 4 times faster than short cylindrical shapes of the same volume. DeSimone notes that the most effective nanoparticles in this regard resemble certain types of bacteria in shape, which quickly infect cells.

Experts have long assumed that copying the characteristic forms of bacteria, fungi, blood cells and even pollen particles would improve the ability of nanoparticles to deliver drugs to diseased cells of the body. However, it was quite difficult to test this hypothesis. To do this, it is necessary to quickly produce billions of particles with identical parameters: size, chemical composition and shape, and then systematically change these parameters and evaluate the effects of these changes.

DeSimone offers a method for the rapid development and testing of a wide range of particle shapes with simultaneous periodic monitoring of their size and chemical composition. For example, it can create nanoparticles of various shapes (boomerangs, donuts, hex nuts, cylinders, cubes), while maintaining a constant volume, create nanoparticles in the form of boomerangs of various sizes, or maintain a constant size and shape, while changing the chemical composition of the particles.

In most cases, researchers work with spherical nanoparticles, because the creation of nanoparticles of other forms is quite difficult. Therefore, the development of DeSimone provides specialists with new, almost unlimited opportunities.

DeSimone also identified the exact mechanisms by which cells absorb nanoparticles of different shapes. These mechanisms determine which compartment of the cell will contain one or another nanoparticle. The new information will allow researchers to create nanoparticles designed to penetrate certain cell organelles with a known level of acidity. They can also "tune" the particles so that they break down and release their cargo when they reach the required cell compartment, which will ensure unprecedented accuracy of drug delivery.

DeSimone uses the technology he developed in the manufacture of nanoparticles to deliver drugs inside tumor cells. He is already starting trials on mice with various types of malignant tumors: breast, ovarian, cervical, lung and prostate cancers, as well as lymphoma. Simultaneous execution of a large number of experiments is possible due to the ease with which various molecules are connected to its nanoparticles. As part of the experiments, DeSimone will systematically change the dosage, nanoparticle sizes and other parameters in order to determine the most effective combinations.

DeSimone has also developed nanoparticles that resemble blood cells in shape, size and flexibility, which allows them to circulate in the bloodstream and not be removed by biological barriers. They are currently being tested on animals as a potential blood substitute basis. Elongated, worm-like nanoparticles that are easily absorbed by macrophages are also tested.

Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of TechnologyReview – Shape Matters for Nanoparticles

01.10.2008