Exploring Raman Spectroscopy as a Detection Tool for Cardiovascular Diseases and Diabetes Mellitus in Fingernails

ABSTRACT The last decade has witnessed the rapid incline of cardiovascular diseases (CVDs) and diabetes mellitus (DM) cases globally. In many cases, the aforementioned diseases have been associated with diagnostic errors, which refer to the late or misdiagnosis of disease/medical condition and lead to further medical complications. The vast majority of diagnostic errors are seen in low‐ and middle‐income countries (LMICs), where medical expenses are limited in terms of equipment/technologies, staffing and training. Traditional diagnostic methods like blood tests, cardiac catheterization and electrocardiograms (ECGs) are costly, invasive and dependent on sophisticated equipment and expert interpretation, making them less suitable for LMICs. This urges for alternative detection tools such as Raman spectroscopy, which offers rapid, non‐intrusive/invasive and non‐destructive analysis. Therefore, this work aimed to explore the feasibility of Raman spectroscopy for the detection of CVDs and/or DM in fingernails. Spectral interpretation revealed peaks corresponding to disease‐related biomarkers such as cytochrome B and C in CVD fingernails and glycated proteins in diabetic fingernails. Additional endogenous compounds were also identified within the fingernails, including amino acids (cysteine, cystine, tyrosine), lipids (cholesterol) and proteins (keratin). While the aforementioned compounds were detected within all fingernails despite the absence/presence of disease, their spectral signature varied based on the participants' age, biological sex and ethnicity. This demonstrated the feasibility of Raman spectroscopy as a detection tool for CVDs and DM, while also removing the invasive and intrusive nature of traditional detection techniques and matrices (blood and urine).