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

Abstract

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 1.0×10-1.0×10 μM, with a low detection limit of 8.17×10 μM (R = 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.

A Highly Sensitive Impedimetric DNA Biosensor Based on Hollow Silica Microspheres for Label-Free Determination of E. coli

“…There was a reduction of R CT values after hollow silica spheres were dropped onto the SPE electrodes due to the positively charged HSMs. As a general rule, silica is negatively charged due to the silanol group, but after the reaction with APTES, silica was positively charged with the presence of the amine group in the silica chain [5]. This was confirmed with zeta potential analysis.…”

“…Tiwari et al [4] explored an electrochemical genosensor for E. coli detection based on graphene oxide, nickel ferrite and chitosan, with methylene blue as the redox indicator. Ariffin et al [5] developed an electrochemical DNA biosensor for E. coli detection based on hollow silica spheres (HSMs), using an anthraquinone redox intercalator as the electroactive DNA hybridization label. However, hollowed silica spheres used as The (3-aminopropyl) triethoxysilane (APTES, 98%), glutaraldehyde, gold nanoparticles powder (AuNPs, <100 nm), potassium chloride (KCl), sodium chloride (NaCl), tetraethyl orthosilicate (TEOS, 98%), and ethanol were purchased from Fluka.…”

A Hydrogen Peroxide Biosensor from Horseradish peroxidase Immobilization onto Acrylic Microspheres

“…The increase of peak current with increased nanoparticle amount was due to the increase of conduction pathway for electron transfer generated by the AuNPs (Ulianas et.al 2011). The decrease in current above 0.07 mg nanoparticles can be related to the complete coverage of nanoparticles on the SPE surface, hence hampering the electron transfer efficiency at the electrode surface (Ariffin et al 2018). Figure 3(b) shows the effect of MSP-NAS amount on the biosensor response.…”

“…This can be explained mainly by the increment of the surface area for HRP enzymes to be immobilized onto the surface as the concentration of MSP-NAS was increased. The total coverage or saturation will hinder the electron transfer and lower the DPV response (Ariffin et al 2018;Ulianas et al 2018). The peak current escalated proportional with the increasing amount of enzymes from 0.08 to 0.19 mg. Further increase caused the current to decrease due to the saturation of the MSP-NAS with HRP enzymes (Figure 3(c)).…”

Label-Free Detection of E. coli O157:H7 DNA Using Light-Addressable Potentiometric Sensors with Highly Oriented ZnO Nanorod Arrays

“…For instance, the detection of Escherichia coli (E. coli) DNA is of great significance to the quality control of food and water. E. coli O157:H7 is one of the most dangerous foodborne pathogens, occurring in a variety of foods and water; it is able to cause hemorrhagic colitis, and leads to various symptoms, such as bloody diarrhea [5][6][7][8]. It is highly desirable to develop novel approaches for the detection of bacterial DNA in a label-free and cost-effective manner.…”