Fast catalytic and electrocatalytic oxidation of sodium borohydride on palladium nanoparticles and its application to ultrasensitive DNA detection
ABSTRACT We report an ultrasensitive DNA sensor using the rapid enhancement of electrocatalytic activity of DNA-conjugated Pd nanoparticles (NPs); the rapid enhancement results from the fast catalytic hydrolysis of NaBH(4) on Pd NPs and subsequent fast hydrogen sorption into Pd NPs.
Conference Paper: System identification using polycepstra with interpolation[Show abstract] [Hide abstract]
ABSTRACT: This paper extends the cepstral calculus based on our novel approach with the frequency-domain interpolation to a multidimensional case. The derived differential polycepstra may be implemented successfully to the system identification even when the system input is excited by symmetrically distributed i.i.d. random noise. We show that the differential polycepstrum of any order shrinks to a one-dimensional differential cepstrum located in two identical replicas, on the x-axis and the main diagonal of the multidimensional cepstral space, if we process the system output signal whose excitation was i.i.d. random white noise. The interpolation-based calculation asymptotically eliminates cepstral aliasing and overlapping of the causal and anticausal part of differential cepstrum. At the same time, the complexity of the computational algorithm is lower compared to the techniques of cepstral aliasing reduction. We reveal this newly derived computational algorithm and depict its strength on identification of two simulated system responsesSignal Processing Proceedings, 2000. WCCC-ICSP 2000. 5th International Conference on; 02/2000
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ABSTRACT: There is a crucial need for simple and highly sensitive techniques to detect DNA in complicated biological samples such as serum. Here we present an ultrasensitive electrochemical DNA sensor using (i) single DNA hybridization with peptide nucleic acid (PNA), (ii) selective binding of [Ru(NH(3))(6)](3+) to hybridized DNA, (iii) fast NaBH(4) electrooxidation mediated by [Ru(NH(3))(6)](3+), and (iv) low background currents of NaBH(4) at indium-tin oxide (ITO) electrodes. The [Ru(III)(NH(3))(5)NH(2)](2+) formed from [Ru(III)(NH(3))(6)](3+) in borate buffer (pH 11.0) is readily electrooxidized to both [Ru(IV)(NH(3))(5)NH(2)](3+) and Ru complex with a higher oxidation state. In the absence of [Ru(NH(3))(6)](3+) bound to the DNA-sensing ITO electrodes, the oxidation currents of NaBH(4) are very low. However, in the presence of [Ru(NH(3))(6)](3+), the oxidation currents of NaBH(4) are highly enhanced due to electron mediation of the oxidized Ru complexes. The significant enhancement in the electrocatalytic activity of sensing electrodes after [Ru(NH(3))(6)](3+) binding facilitates to obtain high signal-to-background ratios. PNA and ethylenediamine on DNA-sensing electrodes significantly decrease [Ru(NH(3))(6)](3+) binding, also allowing for high signal-to-background ratios. The oxidation charges of NaBH(4) obtained from chronocoulometry are highly reproducible. All combined effects enable the detection of DNA with a detection limit of 1 fM in ten-fold diluted human serum. The simple and fast detection procedure and the ultrasensitivity make this approach highly promising for practical DNA detection.Langmuir 05/2010; 26(9):6804-8. DOI:10.1021/la904089e · 4.38 Impact Factor
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ABSTRACT: The electrocatalytic activities of freshly prepared nanomaterials do not represent normal activities, if they change with aging. We report the dependence of the electrocatalytic activity of gold nanoparticles (AuNPs) upon aging. The activities of AuNPs prepared by four different methods (electrodeposition; reduction of Au ions with NaBH4, citrate, and ascorbate, respectively) slowly decrease with aging in the electrooxidation of H2O2 or formic acid, both in air and in solution. The possible origin of this effect is discussed.Electrochemistry Communications 06/2010; 12(9):1245–1248. DOI:10.1016/j.elecom.2010.06.030 · 4.29 Impact Factor