Vibrational spectroscopy as a complementary approach to monitor SH-SY5Y cell differentiation

The SH-SY5Y neuroblastoma cell line is a well-established model for investigating neuronal differentiation, typically induced by sequential treatment with retinoic acid and brain-derived neurotrophic factor to promote neurite outgrowth. In the present study, we examined the evolving spectroscopic signatures of SH-SY5Y cells throughout a seven-day differentiation protocol, consisting of five days of retinoic acid followed by two days of brain-derived neurotrophic factor. Using Fourier-transform infrared spectroscopy spectral analyses focused on the 3050-2800 cm^-1, 1800-1500 cm^-1, and 1500-900 cm^-1 regions to monitor metabolomic changes across different days in vitro. Distinct spectral profiles emerged between early and late differentiation stages, indicating dynamic biochemical remodelling. Late differentiation stage cells exhibited enhanced signals associated with lipid ester groups and β-sheet protein conformations, whereas early-differentiation-stage cells showed features linked to unsaturated lipid CH stretches, parallel and antiparallel β-sheet arrangements, and phosphate monoester groups from nucleic acids. These findings highlight the sensitivity and utility of Fourier-transform infrared spectroscopy for monitoring and characterizing the biochemical dynamics of SH-SY5Y cell differentiation.