Photobiomodulation as an antioxidant substitute in post-thawing trauma of human stem cells from the apical papilla

Sci Rep. 2021 Aug 30;11(1):17329. doi: 10.1038/s41598-021-96841-3.


Cryopreservation, the most common method of preserving stem cells, requires post-processing because it produces trauma to the cells. Post-thawing trauma typically induces cell death, elevates reactive oxygen species (ROS) concentration, and lowers mitochondrial membrane potential (MMP). Although this trauma has been solved using antioxidants, we attempted to use photobiomodulation (PBM) instead of chemical treatment. We used a 950-nm near-infrared LED to create a PBM device and chose a pulsed-wave mode of 30 Hz and a 30% duty cycle. Near-infrared radiation (NIR) at 950 nm was effective in reducing cell death caused by hydrogen peroxide induced-oxidative stress. Cryodamage also leads to apoptosis of cells, which can be avoided by irradiation at 950 nm NIR. Irradiation as post-processing for cryopreservation had an antioxidant effect that reduced both cellular and mitochondrial ROS. It also increased mitochondrial mass and activated mitochondrial activity, resulting in increased MMP, ATP generation, and increased cytochrome c oxidase activity. In addition, NIR increased alkaline phosphatase (ALP) activity, a biomarker of differentiation. As a result, we identified that 950 nm NIR PBM solves cryodamage in human stem cells from the apical papilla, indicating its potential as an alternative to antioxidants for treatment of post-thawing trauma, and further estimated its mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Antioxidants / metabolism*
  • Apoptosis
  • Biomarkers / metabolism
  • Biophysics
  • Cell Biology
  • Cell Death
  • Cell Proliferation / radiation effects
  • Cell Survival / drug effects
  • Cryopreservation
  • Electron Transport Complex IV / metabolism
  • Equipment Design
  • Humans
  • Hydrogen Peroxide / metabolism
  • Hydrogen Peroxide / pharmacology
  • Luminescence
  • Membrane Potential, Mitochondrial*
  • Mitochondria / metabolism
  • Oxidative Stress
  • Phototherapy / methods*
  • Reactive Oxygen Species
  • Spectroscopy, Near-Infrared
  • Stem Cells / cytology*


  • Antioxidants
  • Biomarkers
  • Reactive Oxygen Species
  • Hydrogen Peroxide
  • Electron Transport Complex IV
  • Alkaline Phosphatase