Label-free human-disease characterization through circulating cell free DNA analysis using Raman Spectroscopy

Abstract Circulating cell free DNA (ccfDNA) is a liquid biopsy biomaterial attracting significant attention for the implementation of precision medicine diagnostics. Deeper knowledge related to its structure and biology would enable the development of such applications. In this study, we employ Raman Spectroscopy to unravel the biomolecular profile of human ccfDNA in health and disease. We established reference Raman spectra of ccfDNA samples from healthy males and females, from different conditions including cancer and diabetes, extracting information about their chemical composition. Comparative observations showed a distinct spectral pattern in ccfDNA from breast cancer patients taking neoadjuvant therapy. Raman analysis of ccfDNA from healthy, prediabetic and diabetic males uncovered some differences in their biomolecular fingerprint. We also studied ccfDNA released from human benign and cancer cell lines and compared it to their respective gDNA, confirming mirroring its cellular origin. Overall, we explored for the first time Raman Spectroscopy in the study of ccfDNA and provide spectra of samples from different sources. Our findings introduce Raman Spectroscopy as a new approach to implementing liquid biopsy diagnostics worthing further elaboration.