Why DMSO is mostly used as a solvent for hydrophobic substances for cell study or any other biological study rather than ethanol or any other organic solvent
DMSO has excellent cosolvent properties for short-term toxicity testing of poorly water-soluble compounds, and its use provides a simple and inexpensive approach to screening a variety of hydrophobic chemicals of environmental relevance. Unlike alcohols, it is an aprotic solvent. It “works” where the proton interferes.
This might address some of your questions. The acute toxicity of DMSO is low, and it has less of a denaturing effect than many other solvents. it is not entirely benign or without impact: