July 10, 2012
One of the more promising developments in the field of medical technology involvesthe use of microspheres for targeted drug delivery. In a nutshell, this encompasses creating tiny hollow balls that are filled with a specific drug, which travel directly to a specific organ or area of diseased tissue. Once there, the spheres release their medication, keeping it concentrated where it’s needed while sparing other tissue from any harmful side effects. Recently, a team of scientists from Germany’s Max Planck Institute of Colloids and Interfaces devised a new method of manufacturing such microspheres, which is said to offer several advantages over existing techniques.
The process begins with researchers selecting a microsphere template that’s the same size that they wish the finished product to be – these templates are made from porous calcium carbonate, and can be created in sizes ranging from a few hundred nanometers up to several micrometers.
Next, the required medication is introduced to the template, in the form of nanoparticles. Because the calcium carbonate is so porous, the particles run into it and throughout the sphere. A web-like outer coating of long protein chains (or polymer threads) is subsequently added, surrounding the ball of nanoparticle-infused calcium.
Finally, an acid is used to dissolve the calcium, leaving behind only the nanoparticles enclosed within the protein chains. That outer coating is biocompatible, so it won’t be rejected by the body, and can include biochemical signaling substances that guide the microsphere to its target area. Once there, the coating will biodegrade, releasing the medication.
Other methods for building drug-delivering microspheres take approaches such as getting nanoparticles to cluster together with carrier molecules, although lead scientist Helmuth Möhwald believes that his technique may prove to be superior. “Our process is easier to control, quicker to implement and more cost-effective than the other techniques developed up to now,” he said. “Whether or not industry will adopt the method and develop it further to application maturity remains an open question.”