The prime objective for every life form is to deliver its genetic material, intact and unchanged, to the next generation. However, during the transference of that material mutations and chemical modifications can occur resulting in variations in the DNA. An inability to respond repairing that DNA damage leads to genetic instability, which in turn may enhance the rate of suffering cancer. Therefore, the understanding of the role of DNA damage is crucial for improving the knowledge of diseases development. Nowadays, the exploring of the genetic information carried by DNA has become a major scientific challenge, finding a vast set of applications in different fields, such as medical diagnostics, genomic screening, drug analysis, forensic and bioterrorism. The vast majority of current DNA detection methods involves the use of (i) amplification strategies, such as polymerase chain reaction (PCR), which however produce inaccurate end point quantification due to the difficulty in maintaining linear, and (ii) fluorescent reporters as part of the signal transduction, which require costly chemicals and complex chemistry. It seems clear then the imperative need for the development of a technique able to acquire high-value genomic information in a simple, low-cost and high-throughput way.
Nanotechnology, as a field rich in state-of-the-art technologies, arises powerful techniques for the DNA analysis, specifically, by the use of nanoparticles. By modifying the surface chemistry of silver nanoparticles we can achieve a positively charged surface in which DNA is absorbed because of their own negative charge. When this clusters composed of DNA and nanoparticles are irradiated by light there are excited leading to a particular vibration pattern depending on the DNA sequence absorbed. This technique is called SERS (Surface-enhanced Raman Scattering) and offers accurate information of the molecules absorbed near to the surface of the nanoparticles. As a result, highly reproducible and intense signals from the DNA can be acquired, detecting mutations or even chemical modifications on that sequences. The development of that techniques are of key importance for the fast detection of mutations and therefore for the improvement in a near future of diseases diagnosis.