Confocal Raman microscopy to monitor extracellular matrix during dental pulp stem cells differentiation

Regenerative medicine brings promising applications for mesenchymal stem cells, such as dental pulp stem cells (DPSCs). Confocal Raman microscopy, a noninvasive technique, is used to study osteogenic differentiation of DPSCs. Integrated Raman intensities in the 2800 to 3000 cm⁻¹ region (C-H stretching) and the 960  cm⁻¹ peak (ν₁ PO₄³⁻) were collected (to image cells and phosphate, respectively), and the ratio of two peaks 1660 over 1690  cm⁻¹ (amide I bands) to measure the collagen cross-linking has been calculated. Raman spectra of DPSCs after 21 days differentiation reveal several phosphate peaks: ν₁ (first stretching mode) at 960  cm⁻¹, ν₂ at 430  cm⁻¹, and ν₄ at 585  cm⁻¹ and collagen cross-linking can also be calculated. Confocal Raman microscopy enables monitoring osteogenic differentiation in vitro and can be a credible tool for clinical stem cell based research.