Tiny particles found in clothing, cosmetics, food, electronics or furniture enter our bodies and behave in unexpected (sometimes unwanted) ways. However, in the realm of medicine another type of particle called the nanoparticle can bring untold potential. We can load them with drugs, for example, and deliver them precisely to a diseased organ or cell. Mark Davis from the California Institute of Technology has created nanoparticles that deliver siRNA specifically into melanomas. Davis and his colleagues have not shied away from making bold claims about the therapeutic potential of their work. They write:
“When taken together, the data presented here provide the first, to our knowledge, mechanistic evidence of RNAi in a human from an administered siRNA. Moreover, these data demonstrate the first example of dose-dependent accumulation of targeted nanoparticles in human tumours. ….These data demonstrate that RNAi can occur in a human from a systemically delivered siRNA, and that siRNA can be used as a gene-specific therapeutic.” Davis et al. 2010.
CRLX101, another experimental nanoparticle designed to circulate for an extended period in the bloodstream, has been used to carry the drug camptothecin to specific targets and counter the spread of lung cancer. When the drug is coated onto CRLX101 it is active for 40 hours, in contrast to the few minutes of efficacy when delivered on its own. As the drug is released, the rest of the nanoparticle disassembles, and the small individual polymer molecules harmlessly exit the body through the kidneys.
Similar treatments for a variety of cancers have been in existence for several years; however, there are many diseases for which a cure is still not available. An enormous amount of data need to be collected and analyzed for each organ. In disease states, certain genes will be over expressed while others are under expressed.
Systems medicine involves examining normal versus sick gene expression levels in any one organism, profiling DNA and any associated modifications, identifying RNA species associated with the disease state and looking into the resulting expression of proteins and metabolites.
Once scientists profile an organ and learn about the key players in the onset of disease, they have to efficiently detect changes in expression. A small blood drop, or cheek swab can be easily collected. But fast methods that can be used to screen a sample directly have yet to be developed. One prototype nano-machine chip has been designed to measure the concentration of twelve prostate cancer associated proteins from a single blood drop. The screening is performed within 10 minutes, at a very low cost. According to Dr. Anna Barker in next two decades we will see real progress in the area of very complex constructs that can detect disease, deliver drugs, and monitor and treat patients.
Nanoshells, nanodevices, nanorobots and individual genome sequencing techniques are all offering insights into the human body in ways that until recently would have only existed in the realm of science fiction. On a personal note, when I was recently asked about my diet, my exercise levels, my life habits and my family genetic history, I could not help but conclude that humanity is at a turning point in its existence – one in which the materialistic complexity of the biological sciences is meeting up with the spiritual complexity of Asian Traditional Medicine.
Nel A. et al. (2006) Toxic Potential of Materials at the Nanolevel. Science Vol. 311 no. 5761 pp. 622-627
Davis M.E. et al. (2010) Evidence of RNAi in humans from systemically administered siRNA via targeted nanoparticles Nature 464, 1067-1070 (15 April 2010)
U.S. National Institute of Health Nanotechnology in Clinical Trials
Auffray C. et al. (2009). Systems medicine: the future of medical genomics and healthcare Genome Med Vol. 1, Issue 1, Article 2.
Anna B. (2010). NIH Podcast Episode #0117
Traditional Asian Medicine (2011) Nature Supplement Vol. 480 No. 7378_supp ppS81-S121.