Scientists develop silicon-based delivery method for transporting drugs around the human body

Scientists from a number of universities in Finland are collaborating on the development of a silicon-based delivery method for transporting drugs around the human body. Among other advances, the researchers say the project could facilitate the use of nanotechnology as a way of combating obesity and controlling appetite. The study is part of the Academy of Finland's Research Programme on Nanoscience (FinNano).

The researchers have discovered that different types of drug molecules can be bound to the porous structure of silicon, thereby making it possible to alter their properties and control their behaviour within the body.

As porous silicon can be produced as both micro- and nanoparticles, the material can enter the body using a range of delivery methods - orally, by injection or using subcutaneous applications. Furthermore biodegradable nanoparticles can be used for drug targeting.

Although silicon is typically used as a raw material in computer microprocessors, in nanomedicine applications the wafers are equipped with nano-sized pores instead of processors. The pores are slightly larger than the drug molecules loaded in them. The porous surfaces of the silicon particles, created through a process called electrochemical etching, are modified to be chemically suitable regarding the molecules to be loaded in the pores. The drug is loaded by immersing the particles in a suitable drug solution, whereby sensitive substances, such as peptides and proteins, can also be loaded into the pores effectively.

The biopharmaceutical properties of the drug in the pores are different from those of the original drug. Selecting the proper pore size and surface chemical properties in relation to the size and chemical properties of the drug molecule controls the rate of release for pore bound drugs.

The drug can be rapidly released and dissolved from the pores. The release of the drug can also be delayed, if the aim is to sustain a therapeutic effect. Porous particles can be targeted to specific tissues in the body by attaching targeting molecules to their surface, whereby a significant amount of the drug loaded in the pores accompanies the particles to the effect site. This would increase, for example, the effectiveness of cancer treatments and reduce side effects.

Nanoporous silicon is applicable as an adjuvant component for both traditional drugs and for peptides, proteins and genetic drugs. The development of silicon as an adjuvant material for medicinal products is based on interdisciplinary research in which physicists, pharmacists, physicians, biotechnologists, chemists, and experts in the material sciences work in cooperation within a broad national research network. The network includes groups from the Finnish universities of Kuopio, Turku, Helsinki and Oulu, as well as from Lappeenranta University of Technology.