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. Author manuscript; available in PMC: 2010 Mar 8.
Published in final edited form as: Adv Funct Mater. 2010;20(1):131–137. doi: 10.1002/adfm.200901311

Figure 1.

Figure 1

Schematic diagram of the gradient generation and stabilization by photopolymerization. A) the gradient generation device consists of a PDMS mold reversibly sealed to a TMS-PMA treated glass slide, B) the channel was pre-filled with low concentration of PEG-DA precursors from the outlet and a high concentration of PEG-DA precursors containing chemicals of interest was introduced from the inlet, C) the solution of interest flowed spontaneously into the channel by passive-pumping-induced forward flow, D) the gradient was generated by the combined effect of evaporation-induced backward flow and molecular diffusion, E) the gradient was stabilized by photopolymerization, F) the hydrogel gradient was obtained after demolding.