Immobilization of trypsin on poly(urea-formaldehyde)-coated fiberglass cores in microchip for highly efficient proteolysis

Trypsin was covalently immobilized on poly(urea-formaldehyde)-coated fiberglass cores based on the condensation reaction between poly(urea-formaldehyde) and trypsin for efficient microfluidic proteolysis in this work. Prior to use, a piece of the trypsin-immobilized fiber was inserted into the main channel of a microchip under a magnifier to form a core-changeable bioreactor. Because trypsin was not permanently immobilized on the channel wall, the novel bioreactor was regenerable. Two standard proteins, hemoglobin (HEM) and lysozyme (LYS), were digested by the unique bioreactor to demonstrate its feasibility and performance. The interaction time between the flowing proteins and the immobilized trypsin was evaluated to be less than 10 s. The peptides in the digests were identified by MALDI-TOF MS to obtain PMF. The results indicated that digestion performance of the microfluidic bioreactor was better than that of 12-h in-solution digestion.