title: Dual-luminophore-labeled gold nanoparticles with completely resolved emission for the simultaneous imaging of MMP-2 and MMP-7 in living cells under single wavelength excitation.
abstract: Although considerable effort has been devoted to the design of various nanoprobes for the fluorescent detection of multiple biomarkers in a single assay, they often suffer from emission-overlapping, owing to small Stokes shifts and wide emission spectra, which results in cross-talk and inaccurate quantification. Herein, we report the design and synthesis of a new nanoprobe for multienzyme detection with completely resolved emission peaks under single-wavelength excitation. The probe was assembled by attaching a cleavable peptide spacer, which was comprised from a matrix metalloproteinase-2 (MMP-2) substrate and a MMP-7 substrate, onto the surface of gold nanoparticles (AuNPs) through cysteine residues. A lanthanide complex, BCTOT-Eu(III) (BCTOT=1,10-bis(5'-chlorosulfo-thiophene-2'-yl)-4,4,5,5,6,6,7,7-octafluorodecane-1,3,8,10-tetraone), and 7-amino-4-methylcoumarin (AMC) were attached to the N terminus and the C terminus of the peptide, respectively. In the presence of one or both targeting enzymes, the substrate was cleaved and fluorescence resonance energy transfer (FRET) between the dyes and AuNPs was prohibited, thereby resulting in the dramatic fluorescence emission of dyes. Importantly, there was no emission cross-talk between the two dyes, thereby ensuring accurate detection of each enzyme. Based on this, the simultaneous fluorescence image of MMP-2 and MMP-7 was accomplished in living cells under single wavelength excitation. The apparent differences in the fluorescence imaging indicated distinct differences between the expression levels of MMPs between the human normal liver cells and the human hepatoma cells.
authors.affiliation: College of Chemistry, Chemical Engineering, and Materials Science, Engineering Research Center of Pesticide and Medicine Intermediate Clean Production, Ministry of Education, and the Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan 250014, PR China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Xia
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Wenxue
authors.initials: W
authors.lastname: Qi
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Sun
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhao
authors.forename: Bo
authors.initials: B
authors.lastname: Tang
mesh_terms: D005453:Fluorescence; D005456:Fluorescent Dyes / Q000138:chemical synthesis; D006046:Gold / Q000737:chemistry*; D056945:Hep G2 Cells; D006801:Humans; D008099:Liver / Q000166:cytology; D020778:Matrix Metalloproteinase 2 / Q000032:analysis / Q000187:drug effects*; D020783:Matrix Metalloproteinase 7 / Q000032:analysis / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D006046:Gold; D020783:Matrix Metalloproteinase 7; D020778:Matrix Metalloproteinase 2