Identifying the crucial tipping point in the maturation process of cultured neurons using Raman spectroscopy and a dynamic network biomarker (DNB) analysis

The present study aimed to identify crucial tipping points during neuronal development in a post-mitotic state using Raman spectroscopy and a dynamic network biomarker (DNB) analysis. A DNB analysis is a promising method to detect early signal during state transition. We previously developed an in vitro model that mimics neuronal development. The neurodevelopmental model was generated from a principal component analysis (PCA) with a Raman spectral dataset obtained from rat hippocampal neurons cultured for 120 days. In the present study, a DNB analysis was employed to identify the tipping point during the maturation of neurons. We reused the Raman spectral dataset obtained in our previous study. Based on our previous PCA findings, the dataset obtained from neurons after 8 days of culture was used in the DNB analysis. Raman spectral fluctuations were observed after 15 days of culturing. The Raman band of lactate (1048 cm⁻¹) was identified as a DNB Raman band. These results suggest that lactate acts as an energy source and a factor affecting neuronal development. The present study also indicates that PCA effectively established the control group for a DNB analysis.