An ultrasensitive hollow-silica-based biosensor for pathogenic Escherichia coli DNA detection

• Published in: Analytical and bioanalytical chemistry 2018-03, Vol.410 (9), p.2363-2375
• Main Authors: Ariffin, Eda Yuhana, Lee, Yook Heng, Futra, Dedi, Tan, Ling Ling, Karim, Nurul Huda Abd, Ibrahim, Nik Nuraznida Nik, Ahmad, Asmat
• Format: Article
• Language: English
• Subjects: Aminopropyltriethoxysilane; Analytical Chemistry; Anthraquinone; Anthraquinones; Bacteria; Biochemistry; Biosensors; Characterization and Evaluation of Materials; Chemical bonds; Chemistry; Chemistry and Materials Science; Covalent bonds; Crosslinking; Deoxyribonucleic acid; DNA; DNA probes; DNA sequencing; E coli; Electrochemistry; Electrodes; Electron microscopy; Equipment and supplies; Escherichia coli; Fabrication; Field emission microscopy; Food Science; Genetic aspects; Glutaraldehyde; Gold; Hybridization; Immobilization; Laboratory Medicine; Molecular structure; Monitoring/Environmental Analysis; Morphology; Nanoparticles; Nucleotide sequence; Pores; Production processes; Quantitation; Research Paper; Scanning electron microscopy; Silica; Silicon dioxide; Sonication; Surface area
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-018-0893-1

A novel electrochemical DNA biosensor for ultrasensitive and selective quantitation of Escherichia coli DNA based on aminated hollow silica spheres (HSiSs) has been successfully developed. The HSiSs were synthesized with facile sonication and heating techniques. The HSiSs have an inner and an outer surface for DNA immobilization sites after they have been functionalized with 3-aminopropyltriethoxysilane. From field emission scanning electron microscopy images, the presence of pores was confirmed in the functionalized HSiSs. Furthermore, Brunauer–Emmett–Teller (BET) analysis indicated that the HSiSs have four times more surface area than silica spheres that have no pores. These aminated HSiSs were deposited onto a screen-printed carbon paste electrode containing a layer of gold nanoparticles (AuNPs) to form a AuNP/HSiS hybrid sensor membrane matrix. Aminated DNA probes were grafted onto the AuNP/HSiS-modified screen-printed electrode via imine covalent bonds with use of glutaraldehyde cross-linker. The DNA hybridization reaction was studied by differential pulse voltammetry using an anthraquinone redox intercalator as the electroactive DNA hybridization label. The DNA biosensor demonstrated a linear response over a wide target sequence concentration range of 1.0×10 -12 –1.0×10 -2 μM, with a low detection limit of 8.17×10 -14 μM ( R 2 = 0.99). The improved performance of the DNA biosensor appeared to be due to the hollow structure and rough surface morphology of the hollow silica particles, which greatly increased the total binding surface area for high DNA loading capacity. The HSiSs also facilitated molecule diffusion through the silica hollow structure, and substantially improved the overall DNA hybridization assay. Graphical abstract Step-by-step DNA biosensor fabrication based on aminated hollow silica spheres