(634g) Polyethylene Glycol (PEG) Gel Arrays for Differentiating Oligopeptide Fragments and on-Chip Protease Assays

Polyethylene glycol (PEG) hydrogel is permeable to biomolecules, but its permeability depends on molecular weight of monomers, the concentration of monomers, and degree of cross-linking. Herein, we report several PEG hydrogels which are only permeable to amino acids but not short oligopeptides. These hydrogels are cross-linked by UV and can be patterned on a glass slide as a micropillars or gel arrays to distinguish short oligopeptides from amino acids. Based on this principle, a gel-array protease assay is developed on a chip for high throughput screening of protease activity. This assay allows simultaneous detection of protease activity in 40 samples with only 1 µl in each sample. The limit of detection is 1 nM which is comparable to most sensitive protease assays. The assay also can be used to distinguish trypsin from chymotrypsin with good specificity, or screen trypsin inhibitors such as benzamidine hydrochloride with high sensitivity. This gel-assay protease assay is a useful tool for high throughput detection of proteases and protease inhibitors.