title: Time-resolved single-step protease activity quantification using nanoplasmonic resonator sensors.
abstract: Protease activity measurement has broad application in drug screening, diagnosis and disease staging, and molecular profiling. However, conventional immunopeptidemetric assays (IMPA) exhibit low fluorescence signal-to-noise ratios, preventing reliable measurements at lower concentrations in the clinically important picomolar to nanomolar range. Here, we demonstrated a highly sensitive measurement of protease activity using a nanoplasmonic resonator (NPR). NPRs enhance Raman signals by 6.1 x 10(10) times in a highly reproducible manner, enabling fast detection of proteolytically active prostate-specific antigen (paPSA) activities in real-time, at a sensitivity level of 6 pM (0.2 ng/mL) with a dynamic range of 3 orders of magnitude. Experiments on extracellular fluid (ECF) from the paPSA-positive cells demonstrate specific detection in a complex biofluid background. This method offers a fast, sensitive, accurate, and one-step approach to detect the proteases' activities in very small sample volumes.
authors.affiliation: Nanoscale Science and Engineering Center, University of California, Berkeley, CA 94720, USA. c-sun@northwestern.edu
authors.forename: Cheng
authors.initials: C
authors.lastname: Sun
authors.forename: Kai-Hung
authors.initials: KH
authors.lastname: Su
authors.forename: Jason
authors.initials: J
authors.lastname: Valentine
authors.forename: Yazmin T
authors.initials: YT
authors.lastname: Rosa-Bauza
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Ellman
authors.forename: Omeed
authors.initials: O
authors.lastname: Elboudwarej
authors.forename: Bipasha
authors.initials: B
authors.lastname: Mukherjee
authors.forename: Charles S
authors.initials: CS
authors.lastname: Craik
authors.forename: Marc A
authors.initials: MA
authors.lastname: Shuman
authors.forename: Fanqing Frank
authors.initials: FF
authors.lastname: Chen
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
mesh_terms: D045744:Cell Line, Tumor; D057075:Enzyme Assays / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007700:Kinetics; D008297:Male; D036103:Nanotechnology; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000201:enzymology; D013997:Time Factors
chemical_list: D017430:Prostate-Specific Antigen