title: Amplified amperometric aptasensor for selective detection of protein using catalase-functional DNA-PtNPs dendrimer as a synergetic signal amplification label.
abstract: In this work, we present a new strategy to construct an electrochemical aptasensor for sensitive detection of platelet-derived growth factor BB (PDGF-BB) based on the synergetic amplification of a three-dimensional (3D) nanoscale catalase (CAT) enzyme-functional DNA-platinum nanoparticles (PtNPs) dendrimer through autonomous layer-by-layer assembly. Firstly, polyamidoaminedendrimer (PAMAM) with a hyper-branched and three-dimensional structure was served as nanocarriers to coimmobilize a large number of PDGF-BB binding aptamer (PBA II) and ssDNA 1 (S1) to form PBA II-PAMAM-S1 bioconjugate. In the presence of PDGF-BB, the bioconjugate was self-assembled on the electrode by sandwich assay. Following that, the carried S1 propagated a chain reaction of hybridization events between CAT-PtNPs-S1 and CAT-PtNPs-ssDNA 2 (S2) to form a 3D nanoscale CAT-functional PtNPs-DNA dendrimer, which successfully immobilized substantial CAT enzyme and PtNPs with superior catalysis activity. In this process, the formed negatively charged double-helix DNA could cause the intercalation of hexaammineruthenium(III) chloride (RuHex) into the groove via electrostatic interactions. Thus, numerous RuHex redox probes and CAT were decorated inside/outside of the dendrimer. In the presence of H2O2 in electrolytic cell, the synergistic reaction of CAT and PtNPs towards electrocatalysis could further amplify electrochemical signal. Under optimal condition, the CAT-PtNPs-DNA dendrimer-based sensing system presented a linear dependence between the reduction peak currents and logarithm of PDGF-BB concentrations in the range of 0.00005-35 nM with a relatively low detection limit of 0.02 pM.
authors.affiliation: Key Laboratory of Ministry of Education of Luminescence and Real-Time Analytical Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Ministry of Education of Luminescence and Real-Time Analytical Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Yali
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Ministry of Education of Luminescence and Real-Time Analytical Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Shun
authors.initials: S
authors.lastname: biXie
authors.affiliation: Key Laboratory of Ministry of Education of Luminescence and Real-Time Analytical Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yaqinchai@swu.edu.cn.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Key Laboratory of Ministry of Education of Luminescence and Real-Time Analytical Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yuanruo@swu.edu.cn.
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
mesh_terms: D052157:Aptamers, Nucleotide / Q000235:genetics*; D002374:Catalase / Q000235:genetics; D003217:Conductometry / Q000295:instrumentation*; D050091:Dendrimers / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation*; D010984:Platinum / Q000737:chemistry*; D011506:Proteins / Q000032:analysis* / Q000235:genetics*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods
chemical_list: D052157:Aptamers, Nucleotide; D050091:Dendrimers; D011506:Proteins; D010984:Platinum; D002374:Catalase
keywords: Aptasensor; Catalase-functional DNA–PtNPs dendrimer; Dual signal amplification; Three-dimensional nanoscale