title: Immobilization of aptamer-modified gold nanoparticles on BiOCl nanosheets: Tunable peroxidase-like activity by protein recognition.
abstract: A self-assembled nanocomposite is prepared from an aqueous mixture of aptamer-modified gold nanoparticles (Apt-Au NPs), bismuth ions and chloride ions. The Apt-Au NPs are immobilized on bismuth oxychloride (BiOCl) nanosheets in situ to form Apt-Au NPs/BiOCl nanocomposites. The as-prepared nanocomposites exhibit high peroxidase-like activity for the catalytic conversion of Amplex Red (AR) to fluorescent resorufin in the presence of H2O2. The catalytic activity of Apt-Au NPs/BiOCl nanocomposites is at least 90-fold higher than that of Apt-Au NPs or BiOCl nanosheets, revealing synergistic effects on their activity. The catalytic activity of Apt-Au NPs/BiOCl nanocomposites is suppressed by vascular endothelial growth factor-A165 (VEGF-A165) molecules that specifically interact with the aptamer units (Del-5-1 and v7t-1) on the nanocomposite surface. The AR/H2O2-Apt-Au NPs/BiOCl nanocomposites probe shows high selectivity (>1000-fold over other proteins) and sensitivity (detection limit ~0.5nM) for the detection of VEGF-A165. Furthermore, the probe is employed for the detection of VEGF isoforms and for the study of interactions between VEGF and VEGF receptors. The practicality of this simple, rapid, cost-effective probe is validated by the analysis of VEGF-A165 in cell culture media, showing its great potential for the analysis of VEGF in biological samples.
authors: Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
authors: Chia-Lun
authors: CL
authors: Hsu
authors: Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
authors: Chia-Wen
authors: CW
authors: Lien
authors: Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
authors: Chia-Wei
authors: CW
authors: Wang
authors: Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
authors: Scott G
authors: SG
authors: Harroun
authors: Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan; School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan. Electronic address: huanging@ntou.edu.tw.
authors: Chih-Ching
authors: CC
authors: Huang
authors: Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan. Electronic address: changht@ntu.edu.tw.
authors: Huan-Tsung
authors: HT
authors: Chang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D001729:Bismuth / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D010544:Peroxidases / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D042461:Vascular Endothelial Growth Factor A / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide; D009841:Oligonucleotides; D042461:Vascular Endothelial Growth Factor A; C044685:bismuth oxychloride; D006046:Gold; D006861:Hydrogen Peroxide; D010544:Peroxidases; D001729:Bismuth
keywords: Aptamers; Enzyme; Nanoparticles; Self-assembly; Synergistic effects