Electrostatic modification of ferritin onto polypeptide-functionalized indium oxide electrode surfaces: Electrochemical and AFM studies

Tominaga, Masato; Soejima, Kazuki; Matsumoto, Manabu; Taniguchi, Ikuo

doi:10.1016/j.jelechem.2005.01.024

Cited by 19 publications

(17 citation statements)

References 24 publications

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“…In this work, the oligonucleotide probes are immobilized onto a screenprinted carbon electrode (SPCE) surface, previously modified with polylysine, through electrostatic interactions. Although the high affinity between DNA and (poly)lysine, has been exploited to immobilize DNA onto different solid surfaces in many biological applications (Bussiek et al, 2003;Segura et al, 2003) and in the development of enzymatic electrochemical sensors (Tominaga et al, 2005;Tsujimura et al, 2005), to the best of our knowledge polylysine has not been used yet to capture ssDNA through electrostatic interactions onto SPCEs for the development of DNA hybridization sensors. Polylysine has also been frequently used in the design of DNA microarrays, but in these devices the immobilization of the oligonucleotide is usually performed through covalent attachment with the free amino groups of the polylysine using bifunctional linkers (Wu et al, 2005;Strother et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

DNA hybridization biosensors using polylysine modified SPCEs

Díaz‐González

Escosura‐Muñiz

González‐García

et al. 2008

Biosensors and Bioelectronics

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Two electrochemical DNA hybridization biosensors (genosensors) for the detection of a 30-mer sequence unique to severe acute respiratory syndrome (SARS) virus are described in this work. Both genosensors rely on the hybridization of the oligonucleotide target with its complementary probe, which is immobilized on positively charged polylysine modified screen-printed carbon electrodes (SPCEs), through electrostatic interactions. In one design, a biotinylated target is used and the detection of the hybridization reaction is monitored using alkaline phosphatase labeled streptavidin (S-AP). This enzyme catalyzes the hydrolysis of the substrate 3-indoxyl phosphate (3-IP) to indigo, which is then solubilized to indigo carmine and detected by means of cyclic voltammetry (CV). In the other design, the target is labeled using an Au(I) complex, sodium aurothiomalate, and the duplex formation is detected by measuring, for first time, the current generated by the hydrogen evolution catalyzed by the gold label. Using 30 min of hybridization time, a detection limit of 8 pM is calculated for the enzymatic genosensor. Although this good sensitivity cannot be reached with the metal label (0.5 nM), the use of this label allows a considerable decrease of the analysis time. Both genosensors do not require the modification of the oligonucleotide probe and using stringent experimental conditions (60 min of hybridization time and 50% formamide in the hybridization buffer) can discriminate between a complementary oligonucleotide and an oligonucleotide with a three-base mismatch.

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Section: Introductionmentioning

confidence: 99%

DNA hybridization biosensors using polylysine modified SPCEs

Díaz‐González

Escosura‐Muñiz

González‐García

et al. 2008

Biosensors and Bioelectronics

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“…NTA diffused into the cavity would directly react with the ferritin core consisting of iron(III) ions, resulting in (NTA)-Fe(III) and/or bis(NTA)-Fe(III) complex formation. Complex formation is accelerated when ferritin core iron(III) ions are reduced to iron(II) ions by a chemical agent or electrochemical reactions [25,32,33]. After ferritin immobilized onto 3-APMS modified silicon surfaces was immersed into a phosphate buffer solution of 10 µmol dm −3 NTA for 20 min, ferritin molecules immobilized onto silicon surfaces were observed by AFM measurements.…”

Section: Resultsmentioning

confidence: 99%

“…The concentration of purified ferritin was determined by the BCA-protein reaction (BCAprotein assay kit, PIERCE Chem. Comp., USA) against an albumin standard curve [25]. The number of iron atoms per ferritin molecule used in this study was evaluated to be approximately 3.3 × 10 3 atoms by inductively coupled plasmaatomic emission and atomic absorption spectroscopies.…”

Section: Methodsmentioning

confidence: 99%

“…To remove adsorbed organic contaminants on silicon surfaces, surfaces were treated by immersion into 30% H 2 O 2 :30% NH 4 OH:water (1:1:5(v/v)) for 10 min with sonication and for 30 min at 60 • C. Silicon surfaces were washed with water several times with sonication and finally washed with ethanol. Clean silicon surfaces were modified with 3-aminopropyltrimethoxysilane (3-APMS, AZmax Co., Japan) according to a method described in a previous paper [25]. Ferritin was immobilized onto 3-APMS-modified silicon surfaces by immersion of substrates into a phosphate buffer solution (pH 7, μ = 0.1) of 0.02-0.2 µmol dm −3 ferritin for 10 s. A nitrilotriacetic acid (NTA, Nacalai Tessque Co., Japan) was used as an iron ion chelator.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Size control for two-dimensional iron oxide nanodots derived from biological molecules

Tominaga

Matsumoto

Soejima

et al. 2006

Journal of Colloid and Interface Science

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“…Both negatively-and positively-charged peptides can be immobilized on the ITO surface by the layer-by-layer assembly method, as already shown by many researchers in their work. 23 Alternatively, silane chemistry can be employed to immobilize peptides to the surface covalently, which is not limited to charged peptides.…”

Section: +mentioning

confidence: 99%

Label-free electrochemical differentiation of phosphorylated and non-phosphorylated peptide by electro-catalyzed tyrosine oxidation

Wan

Guo

2008

Analyst

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Protein phosphorylation plays an important role in many significant cellular processes, and has thus gained tremendous interest in the field of proteomics. The electro-active tyrosine residue, as an important receptor of phosphorylation in proteins, exhibits electro-inactivity after being phosphorylated on the hydroxy group of its aromatic ring. In this study, the electrochemical oxidation of tyrosine on indium tin oxide (ITO) electrodes was catalyzed with an electron mediator Os(bpy) 3 2+ (bpy = 2,2 -bipyridine) and was employed as a signal reporter to differentially detect non-phosphorylated and phosphorylated peptides. A short, tyrosine-containing peptide glu-glu-glu-glu-glu-tyr (EY-6) was immobilized on an ITO surface using the layer-by-layer self-assembly method, and was detected by cyclic voltammetry in an Os(bpy) 3 2+ solution. The limit of detection was about 0.23 lg mL −1 EY-6 in solution. The phosphorylated peptide glu-glu-glu-glu-glu-tyr-OP (EY-6P) did not produce an appreciable oxidation current on the electrode. Surface plasmon resonance measurements revealed that the amount of EY-6 and EY-6P adsorbed on the sensor chip surface was 269 and 378 pg mm −2 , respectively. The poly(glu, tyr) (4 : 1) peptide, a protein tyrosine kinase substrate, was also detected by the same approach, with a detection limit of 0.65 lg mL −1 . This new approach offers the possibility of label-free and on-chip detection of protein tyrosine kinase activity.

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Electrostatic modification of ferritin onto polypeptide-functionalized indium oxide electrode surfaces: Electrochemical and AFM studies

Cited by 19 publications

References 24 publications

DNA hybridization biosensors using polylysine modified SPCEs

DNA hybridization biosensors using polylysine modified SPCEs

Size control for two-dimensional iron oxide nanodots derived from biological molecules

Label-free electrochemical differentiation of phosphorylated and non-phosphorylated peptide by electro-catalyzed tyrosine oxidation

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