title: A sensitive colorimetric label-free assay for trypsin and inhibitor screening with gold nanoparticles.
abstract: Gold nanoparticles (Au-NPs) with negative charges aggregate in the presence of Arg(6) due to electrostatic interactions resulting in the red-shift of the plasmon absorption. But, after incubation of Arg(6) with trypsin the aggregation of Au-NPs can be prohibited. Accordingly, a newly designed-Au-NPs based colorimetric assay method for trypsin activity is established. Trypsin with a concentration as low as 1.6 ng mL(-1) can be assayed with this new colorimetric assay. This colorimetric label-free assay for trypsin can be performed in aqueous solution and both Au-NPs and Arg(6) are easily accessible. Thus, this assay method is useful for screening inhibitors of trypsin.
authors.affiliation: Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Wangxin
authors.initials: W
authors.lastname: Xue
authors.forename: Guanxin
authors.initials: G
authors.lastname: Zhang
authors.forename: Deqing
authors.initials: D
authors.lastname: Zhang
mesh_terms: D000818:Animals; D003124:Colorimetry / Q000379:methods; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D013552:Swine; D014357:Trypsin / Q000032:analysis / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000494:pharmacology*
chemical_list: D014361:Trypsin Inhibitors; D006046:Gold; D014357:Trypsin