Here is a nice paper on ES collagen using acetic acid and DMSO as solvents. https://www.researchgate.net/publication/276146957_Electrospun_type_1_collagen_matrices_preserving_native_ultrastructure_using_benign_binary_solvent_for_cardiac_tissue_engineering
Article Electrospun type 1 collagen matrices preserving native ultra...
I would suggest using an organic solvent with low boiling point such as 1,1,1,3,3,3 hexafluoro-2-propanol (HFP)
using an A low boiling point solvent is favourable for the electrospinning process as it evaporates under the atmospheric condition and leaves a polymer in the dry state.
generally, you can also dissolve collagen is acids including HCL and acetic acid as well (10 mM hydrochloric acid, or 0.5 M acetic acid does the job after stirring for few hours (e.g. 5)
besides the solvent parameters such as Flow rate, applied electric field, collecting distance and composition of the starting solution effect on the morphology of the obtained fibres. Plus the addition of polymer such as PEO and salt (NaCl) help to achieve a trouble free smooth homogeneous spinning process
I feel 1,1,1,3,3,3 hexafluoro-2-propanol (HFP) would be an ideal solvent to solubilize collagen for electrospinning. My personal experience with acetic acid and DMSO was not successful and i also think that for cell culture applications if there is DMSO left in the scaffold it might be detrimental. As HFP is an volatile solvent, there will hardly traces found after electrospinning process. But its still a debate for everyone whether to use HFP or acetic acid with respect to cytotoxicity. I always have good experiences using HFP.