title: Amplified QCM-D biosensor for protein based on aptamer-functionalized gold nanoparticles.
abstract: A highly sensitive quartz crystal microbalance with dissipation monitoring (QCM-D) biosensor for protein was developed using aptamer-functionalized gold nanoparticles (Apt-GNPs) for amplification. Human α-thrombin, an important physiological protease found in blood, was chosen as the target protein. Captured by immobilized aptamers, thrombin was determined on-line using Apt-GNPs to enhance both frequency and dissipation signals. The fabricated sandwich of aptamer/thrombin/Apt-GNPs on chip surface was confirmed by atomic force microscopy (AFM). Compared to direct assay, the detection limit for thrombin was down to 0.1 nM, yielding about 2 orders of magnitude improvement in sensitivity. This aptamer-based QCM-D biosensor also showed good selectivity and repeatability in complex matrix. For the first time, the dual-signal enhancement of Apt-GNPs on QCM-D sensing was demonstrated, and such design could provide a promising detection strategy for proteins with two binding sites.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.forename: Dingzhong
authors.initials: D
authors.lastname: Wang
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Wu
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
mesh_terms: D000669:Amplifiers, Electronic; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D006801:Humans; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D013917:Thrombin