Nanophotonic waveguide-based sensing of circulating cell-free mitochondrial DNA: implications for personalized medicine

[Display omitted] •The inherent instability of mitochondrial DNA (mtDNA) is one of the causes of human ailments.•The release of circulating cell-free mtDNA (ccf-mtDNA) represents a common feature in various systemic diseases, making it a potential biomarker.•Analytical methods such as droplet digital polymerase chain reaction (PCR), next-generation sequencing and multiplex real-time PCR can be used to detect and analyze ccf-mtDNA.•Using fluorescent labels alongside planar optical waveguides enhances the detection of ccf-mtDNA. Circulating cell-free mitochondrial DNA (ccf-mtDNA) has emerged as a promising biomarker, with potential implications for disease diagnosis. Changes in mtDNA, such as deletions, mutations or variations in the number of copies, have been associated with mitochondrial disorders, heart diseases, cancer and age-related non-communicable diseases. Previous methods, such as polymerase chain reaction-based approaches, next-generation sequencing and imaging-based techniques, have shown improved accuracy in identifying rare mtDNA variants or mutations, but they have limitations. This article explains the basic principles and benefits of using planar optical waveguide-based detection devices, which represent an advanced approach in the field of sensing.