title: Fluorogenic quantum dot-gold nanoparticle assembly for beta secretase inhibitor screening in live cell.
abstract: We have developed a novel fluorogenic nanoprobe prepared from the assembly of CdSe/ZnS quantum dot (QD) and gold (Au) nanoparticles in which QD was conjugated with a specifically designed β-secretase (BACE1) substrate peptide, which was allowed to bind to the Ni-nitrilotriacetate (Ni-NTA) modified Au nanoparticles. This coordination-mediated binding of the QD with Au nanoparticles via Ni-NTA-histidine (His) interaction resulted in highly efficient quenching of QD fluorescence through a distance-dependent fluorescence resonance energy transfer (FRET) phenomenon. The prequenched QD-Au assembly recovered the fluorescence in the presence of the BACE1 enzyme after incubation in vitro. The high quenching efficiency of AuNP and robust QD fluorescence signal recovery upon BACE1 enzymatic digestion enabled us to visualize BACE1 activity in living cells, which further allowed us to generate the half maximal inhibitory concentration (IC(50)) values for BACE1 inhibitors in the cell-based assay utilizing a high throughput system (HTS). These results suggest the potential application of QD-AuNP assembly toward the HTS drug screening system as a robust and efficient probe to identify active molecules in BACE1-related diseases such as Alzheimer's disease.
authors.affiliation: Medicinal Chemistry Laboratory, Institut Pasteur Korea (IP-K), 696 Sampyeong-dong, Bundang-gu, Seongnam-Si, Gyeonggi-Do, 464-400, South Korea.
authors.forename: Youngseon
authors.initials: Y
authors.lastname: Choi
authors.forename: Yoojin
authors.initials: Y
authors.lastname: Cho
authors.forename: Minjung
authors.initials: M
authors.lastname: Kim
authors.forename: Regis
authors.initials: R
authors.lastname: Grailhe
authors.forename: Rita
authors.initials: R
authors.lastname: Song
mesh_terms: D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D045663:Quantum Dots
chemical_list: D004791:Enzyme Inhibitors; D005456:Fluorescent Dyes; D010455:Peptides; D006046:Gold; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human