Developing New Diagnostic Tools Based on SERS Analysis of Filtered Salivary Samples for Oral Cancer Detection

Abstract

Cancer still represents one of the biggest challenges in current medical practice. Among different types of cancer, oral cancer has a huge impact on patients due to its great visibility, which is more likely to create social stigma and increased anxiety. New early diagnose methods are still needed to improve treatment efficiency and patients’ life quality. Raman/SERS (Surface Enhanced Raman Spectroscopy) spectroscopy has a unique and powerful potential for detecting specific molecules that can become priceless biomarkers in different pathologies, such as oral cancer. In this study, a batch of saliva samples obtained from a group of 17 patients with oro-maxillofacial pathologies compared with saliva samples from 18 healthy donors using the aforementioned methods were evaluated. At the same time, opiorphin, potassium thiocyanate and uric acid were evaluated as potential specific biomarkers for oro-maxillofacial pathologies using multivariate analysis. A careful examination of SERS spectra collected on saliva samples showed that the spectra are dominated by the vibrational bands of opiorphin, potassium thiocyanate and uric acid. Given the fact that all these small molecules are found in very small amounts, we filtrated all the samples to get rid of large molecules and to improve our analysis. By using solid plasmonic substrates, we were able to gain information about molecular concentration and geometry of interaction. On the other hand, the multivariate analysis of the salivary spectra contributed to developing a new detection method for oral cancer.

Understanding DNA Epigenetics by Means of Raman/SERS Analysis for Cancer Detection

“…Colloidal silver nanoparticles were obtained according to Leopold and Lendl method [26] using a reduction process of silver nitrate with hydroxylamine hydrochloride. The assynthesized nanoparticles were subjected to a tangential flow filtration (TFF) procedure to concentrate and purify them, in a similar manner to that reported in previous studies, allowing a high reproducibility degree of the SERS spectra recorded on different biofluids [23,25,27]. After this, the 10× concentrated silver nanoparticles were appropriate for use as solid SERS substrates following the method developed by our group a couple of years ago [28].…”

“…Moreover, they allow real-time monitoring of molecular changes, providing insights into the progression of diseases or the response to treatments. Considering these numerous advantages, our research group has achieved remarkable results based on the Raman/SERS technique's ability to distinguish between normal and diseased samples at the molecular level using multivariate analysis tools [23][24][25]. Sample preparation represents a step of ultimate importance in our protocols due to the fact that good-quality probes lead to accurate results.…”

Rapid multi-task diagnosis of oral cancer leveraging fiber-optic Raman spectroscopy and deep learning algorithms

“…This is predominantly achieved through the analysis of hematoxylin and eosin (H&E) tissue sections ( 19 ), frozen sections ( 20 ), and ex-vivo tissues ( 21 ), among other samples. Furthermore, surface-enhanced Raman spectroscopy (SERS) facilitates the diagnosis of oral tumors by analyzing biological specimens such as saliva ( 22 ) and serum ( 23 , 24 ) from patients afflicted with the condition. Up until now, there has been a limited number of studies utilizing Raman spectroscopy for the precise diagnosis of tumor-node-metastasis (TNM) staging and identifying pathological grades such as well differentiated (Grade I), moderately differentiated (Grade II), and poorly differentiated (Grade III).…”