Nanoparticle research is currently an area of intense scientific interest due to a wide variety of potential applications in biomedical, optical and electronic fields. They are also of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures.
The use of nanoparticle distributions in laser dye-doped with poly-methyl methacrylate (PMMA) laser has been shown to improve conversion efficiencies and to decrease laser beam divergence.
A method being developed to fight skin cancer uses gold nanoparticles to which RNA molecules are attached. The nanoparticles are contained in an ointment that is applied to the skin. The nanoparticles penetrate the skin and the RNA molecules attach to a cancer related gene. This method stops the gene from generating proteins that are involved in the growth of skin cancer tumors.
The use of nanotechnology in medicine and more specifically drug delivery is set to spread rapidly. Currently many substances are under investigation for drug delivery and more specifically for cancer therapy. Interestingly pharmaceutical sciences are using nanoparticles to reduce toxicity and side effects of drugs.
For nanoparticles, the situation is different as their size opens the potential for crossing the various biological barriers within the body. From a positive viewpoint, especially the potential to cross the blood brain barrier may open new ways for drug delivery into the brain. In addition, the nanosize also allows for access into the cell and various cellular compartments including the nucleus. A multitude of substances are currently under investigation for the preparation of nanoparticles for drug delivery, varying from biological substances like albumin, gelatin and phospholipids for liposomes, and more substances of a chemical nature like various polymers and solid metal containing nanoparticles. It is obvious that the potential interaction with tissues and cells, and the potential toxicity, greatly depends on the actual composition of the nanoparticle formulation. Besides the potential benefits, also attention is drawn to the questions as to how we should proceed with the safety evaluation of the nanoparticle formulations for drug delivery.
The kind of hazards that are introduced by using nanoparticles for drug delivery are beyond that posed by conventional hazards imposed by chemicals in classical delivery matrices. For nanoparticles the knowledge on particle toxicity as obtained in inhalation toxicity shows the way how to investigate the potential hazards of nanoparticles. The toxicology of particulate matter differs from toxicology of substances as the composing chemical(s) may or may not be soluble in biological matrices, thus influencing greatly the potential exposure of various internal organs. This may vary from a rather high local exposure in the lungs and a low or negligible exposure for other organ systems after inhalation. For such testing the lessons learned from particle toxicity as applied in inhalation toxicology may be of use. Although for pharmaceutical use the current requirements seem to be adequate to detect most of the adverse effects of nanoparticle formulations, it cannot be expected that all aspects of nanoparticle toxicology will be detected. So, probably additional more specific testing would be needed.