Dissolution of biomacromolecules in organic solvents by nano-complexing with poly(ethylene glycol)

Various biomacromolecules (BMs) such as proteins, DNA, and carbohydrates are extremely difficult to be dissolved in a single organic solvent phase for sustained release or targeted delivery formulation. In this study, three different BMs could be solubilized in selected organic solvents by forming poly(ethylene glycol) (PEG)-assisted nano-complexes while maintaining their structural integrity. Dynamic light scattering (DLS) and atomic force microscopy (AFM) analysis revealed that proteins, DNA, and carbohydrate polymers could be nano-complexed with PEG in various organic solvents. The diameter of nano-complexes decreased roughly from ∼600 nm to ∼100 nm with increasing weight ratio of PEG/BM. The present solubilization technique could be potentially applied for sustained release formulations of various therapeutic biological drugs.