Complex precision at the microscale. Using our novel reaction scheme published in Biomacromolecules, the SCBRM lab can now create culture substrates presenting multicomponent polyethylene glycol (PEG) brushes presenting up to three orthogonal surface chemistries (2 are click-reactive, and 1 is inert). This enables precise engineering of complex surface chemistries on cell culture substrates. Circular features are 300mm in diameter.