Currently, in most Latin American countries, tissue fixation in formalin immediately after the biopsy is the common practice. In particular, Raman spectroscopy has a high potential in this field due to the large number of Raman active molecules present in breast cancer tissue. Minimally invasive optical imaging and spectroscopic techniques have the potential to improve the early diagnosis of breast cancer. Even in developed countries like the United States, the breast cancer claims the lives of 40,000 women per year. The development of appropriate diagnostic tools is critical to overcome this disease. Adenocarcinoma starts in glandular tissue and is the most common type of breast carcinoma. Mortality rates of breast cancer have increased in the last 40 years in most Latin American countries. This adsorption promotes the specific interaction and localization of the metallic nanoparticles at suitable distances from target biomolecules, generating the optimal conditions for SERS. The use of gold-modified silica particles for SERS has been widely reported in biological applications due to their strong adsorption of biomolecules. Due to the relationship between this radiation and the incident light, certain areas near the metallic nanoparticles will show an enhancement in the local electromagnetic field. When the excitation photon is resonant with the dipolar plasmon of a metallic nanostructure, the nanoparticle will emit light characteristic of dipolar radiation. Effective SERS depends on the increase in the Raman cross-section as a result of the excitation of surface plasmons, which are collective oscillations of the conduction band electrons. SERS increases the Raman signals of molecules near metal nanostructures, which are typically composed of noble metals such as gold and silver.
To overcome this issue, surface-enhanced Raman spectroscopy (SERS) has been used as an ultrasensitive and non-destructive spectroscopic technique that can provide specific molecular information of analytes present in concentrations relevant to medical applications.
However, for biological samples, it is necessary to decrease the power of the laser source, which results in a reduction of the signal used to extract information from the samples. Raman spectroscopy additionally provides substantial information about the sample identity. Recent uses of Raman spectroscopy in biomedicine have been specifically aimed toward clinical examinations related to the detection of malignancies and cancers in tissues. Raman spectroscopy is a powerful technique used to identify the energy levels of the bonds present in a molecule, which are associated with the vibrational modes of specific chemical interactions. However, despite all the outstanding progress that biomedicine has achieved using these tools, there are still several hurdles that need to be resolved, such as improving the poor spatial resolution at molecular level and optimizing methods of sample preparation. Moreover, high spatial resolution microscopy techniques, such as confocal, scanning and transmission electron methods, can characterize the interaction and structures of biospecimens on the nanoscale size regime.
There are several imaging techniques that can provide diagnosis for cancerous specimens, such as targeted molecular imaging, ultrasound with magnetic nanoparticles, and nanoparticle-enhanced magnetic resonance. Some of these changes are highly related to the development of diseases, and may provide important clues for diagnosis. The qualitative and quantitative analysis of biochemical and structural changes due to the interactions of materials with tissues, at the nanoscale, plays a central role in modern biomedicine. All things do not simply scale down in proportion. One of the most famous lectures given by Richard Feynman was in 1959 at the annual meeting of the American Physical Society “There’s plenty of room at the bottom” in which Feynman stated: As we go down in size, there are a number of interesting problems that arise.
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