Since the birth of modern day medicine, during the times of Hippocrates in ancient Greece, the profession has developed from the rudimentary classification of disease into a rigorous science with an inspiring capability to treat and cure. Scientific methodology has distilled clinical diagnostic tools from the early arts of prognosis, which used to rely as much on revelation and prophecy, as intuition and judgement [1]. Over the past decade, research into the interactions between proteins and nanosystems has provided some ingenious and apt techniques for delving into the intricacies of anatomical systems.
In vivo biosensing has emerged as a vibrant field of research, as much of medical diagnosis relies on the detection of substances or an imbalance in the chemicals in the body. The inherent properties of nanoscale structures, such as cantilevers, make them well suited to biosensing applications that demand the detection of molecules at very low concentrations. Measurable deflections in cantilevers functionalised with antibodies provide quantitative indicators of the presence of specific antigens when the two react. Such developments have roused mounting interest in the interactions of proteins with nanostructures, such as carbon nanotubes [3], which have demonstrated great potential as generic biomarkers. Plasmonic properties are also being exploited in sensing applications, such as the molecular sentinel recently devised by researchers in the US. The device uses the plasmonic properties of a silver nanoparticle linked to a Raman labelled hairpin DNA probe to signal changes in the probe geometry resulting from interactions with substances in the environment. Success stories so far include the detection of two specific genes associated with breast cancer [4].
A greater understanding of how RNA interference regulates gene expression has highlighted the potential of using this natural process as another agent for combating disease in personalized medicine. However, the large molecular weight, net negative charge and hydrophilicity of synthetic small interfering RNAs makes it hard for the molecules to cross the plasma membrane and enter the cell cytoplasm. Immune responses can also diminish the effectiveness of this approach. In this issue, Shiri Weinstein and Dan Peer from Tel Aviv University provide an overview of the challenges and recent progress in the use of nanocarriers for delivering RNAi effector molecules into target tissues and cells more effectively [5].
Also in this issue, researchers in Korea report new results that demonstrate the potential of nanostructures in neural network engineering [6]. Min Jee Jang et al report directional growth of neurites along linear carbon nanotube patterns, demonstrating great progress in neural engineering and the scope for using nanotechnology to treat neural diseases.
Modern medicine cannot claim to have abolished the pain and suffering that accompany disease. But a comparison between the ghastly and often ineffective iron implements of early medicine and the smart gadgets and treatments used in hospitals today speaks volumes for the extraordinary progress that has been made, and the motivation behind this research.
References
[1] Wallis F 2000 Signs and senses: diagnosis and prognosis in early medieval pulse and urine texts Soc. Hist. Med.13 265–78
[2] Arntz Y, Seelig J D, Lang H P, Zhang J, Hunziker P, Ramseyer J P, Meyer E, Hegner M and Gerber Ch 2003 Label-free protein assay based on a nanomechanical cantiliever array Nanotechnology14 86–90
[3] Gowtham S, Scheicher R H, Pandey R, Karna S P and Ahuja R 2008 First-principles study of physisorption of nucleic acid bases on small-diameter carbon nanotubes Nanotechnology19 125701
[4] Wang H-N and Vo-Dinh T 2009 Multiplex detection of breast cancer biomarkers using plasmonic molecular sentinel nanoprobes Nanotechnology20 065101
[5] Weinstein S and Peer D 2010 RNAi nanomedicines: challenges and opportunities within the immune system Nanotechnology21 232001
[6] Jang M J, Namgung S, Hong S, and Nam Y 2010 Directional neurite growth using carbon nanotube patterned substrates as a biomimetic cue Nanotechnology21 235102