title: Self-assembly of an upconverting nanocomplex and its application to turn-on detection of metalloproteinase-9 in living cells.
abstract: Upcoversion nanoparticles are an emerging luminescent nanomaterial with excellent photophysical properties that have great benefits in biological sensing. In this study, a luminescent turn-on biosensor for cell-secreted protease activity assay is established based on resonance energy transfer in an upconversion nanoparticle-graphene oxide nano-assembly. The proposed biosensor consists of a blue-emitting upconversion nanoparticle covered with a quenching complex, comprising gelatin as the proteinase substrate and graphene oxide nanosheets as luminescence acceptors. After enzymatic digestion, the upconversion nanoparticles lose the gelatin cover due to the disassembly of the quenching complex, thus the upconverting luminescence in the blue region is restored (a turn-on response). The recovered upconverting luminescence is proportional to the protease concentration; the limit of detection was 12 ng ml(-1). Finally, the upconversion-graphene oxide nanocomplex was successfully applied in the detection of cell-secreted protease-metalloproteinase in MCF-7 cancer cells with high sensitivity and specificity.
authors: School of Integrative Engineering, Chung-Ang University, Heukseok-dong, Dongjak-gu, Seoul 156-756, Korea.
authors: Phuong-Diem
authors: PD
authors: Nguyen
authors: Vu Thanh
authors: VT
authors: Cong
authors: Changyoon
authors: C
authors: Baek
authors: Junhong
authors: J
authors: Min
mesh_terms: D015374:Biosensing Techniques; D002470:Cell Survival; D006108:Graphite; D006801:Humans; D049449:Luminescence; D020780:Matrix Metalloproteinase 9; D053758:Nanoparticles
chemical_list: D006108:Graphite; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9