Optical detection of the spatial structural alteration in the human brain tissues/cells and DNA/chromatin due to Parkinson's disease.

Parkinson's disease (PD) is considered one of the most frequent neurological diseases in the world. There is a need to study the early and efficient biomarkers of Parkinson's, such as changes in structural disorders like DNA/chromatin, especially at the subcellular level in the human brain. We used two techniques, Partial wave spectroscopy (PWS) and Inverse Participation Ratio (IPR), to detect the changes in structural disorder in the human brain tissue samples. It was observed from the PWS experiment that there was an increase in structural disorder in Parkinson's disease tissues/cells when compared to normal tissues/cells using mesoscopic light transport theory. Furthermore, the IPR experiment also showed DNA/chromatin structural alterations that have the same trend and support the PWS results. The increase in mass density in the nuclei components, such as DNA/chromatin, can be linked to the aggregation of alpha-synuclein in the substantia nigra of the brain. This protein deposition is considered a significant cause of neuronal death in the brains of PD patients. We also did a histological analysis of brain tissues, which supports our results from dual photonics techniques. The results show that this dual technique is a powerful approach to detect the changes. Our results highlight the potential of the parameter, related to the structural disorder strength, as an efficient biomarker for PD progress, paving the way for research into early disease detection.