Herein,
an ultrasensitive and novel platform for DNA detection
is reported, which combines DNA-templated silver nanoparticles (AgNPs)
with electrochemical atom transfer radical polymerization signal amplification.
Peptide nucleic acid (PNA) functionalized with thiol was modified
to the Au electrode surface as a probe to specifically capture target
DNA (T-DNA). After Zr4+ binds to phosphate on DNA, the
initiator [α-bromophenylacetic acid (BPAA)] of ATRP is attached
to PNA/DNA heteroduplexes based on the phosphate groups of T-DNA and
carboxylate groups of BPAA via zirconium–phosphate–carboxylate
chemistries. A large number of glyco-syloxyethyl methacrylates (GEMA)
were captured on the formed PNA/DNA duplex via ATRP. Afterwards, the
polysaccharides were oxidized to polymerized aldehydes with sodium
periodate (NaIO4). In addition, AgNPs were deposited on
the electrode surface by silver mirror reaction. The results indicate
that the amount of AgNPs proportional to the T-DNA was quantified
through differential pulse voltammetry. Furthermore, it proves that
the modified electrode has good performance in DNA detection, indicating
that the DNA sensor has high selectivity, high sensitivity, and stable
repeatability. Under the optimal conditions, a good linear relationship
is obtained in the range of 10 aM to 10 pM with the correlation coefficient
of 0.992, and the detection limit is calculated to be as low as 4.725
aM. In addition, the sensor is successfully used to detect DNA in
actual serum samples with satisfactory results, which indicates huge
promise for detecting gene biomarkers and clinical analysis.
Convenient and sensitive detection of biomolecules is of great significance to disease diagnosis. In this work, am etal-free photoinduced atom transfer radicalp olymerization (photoATRP) by ar eductive quenching pathway as an ovel strategy is appliedt oa chieve lung cancerD NA detection. Thiolated PNA is exploited to specifically recognize target DNA, and the initiator of photoATRP is linked to the electrode surface via phosphate-Zr 4 + -carboxylate. Under the excitation of blue light, the reductive quenching path-way is activatedw ith eosin Y( EY) as photoredox catalyst and N,N,N',N'',N'-pentamethyldiethylenetriamine (PMDETA) as electron donor,a nd numerous polymeric chains are formed. Under optimal conditions, the linear range of this strategy is from 0.1 pm to 10 nm (R 2 = 0.989)w ith al imit of detection (LOD) of 1.4 fm (14 zmol in 10 mL). Thev ariety of possible light sourcesf or photoATRP and simple operation endowt his biosensorw ith great potential for practical applications.[a] Dr.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.
In this study, poly(3,4-ethylenedioxythiophene) (PEDOT) and polyaniline (PANI) were electrodeposited via cyclic voltammetry (CV) on glass carbon electrode (GCE) layer by layer. The prepared electrode (GCE/PEDOT/PANI) was used for the simultaneous sensitive determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA) at different oxidation potentials. The peak distances of AA and DA, DA and UA, AA and UA were 216 mV, 104 mV, 320 mV, respectively. For individual detection of AA, DA and UA, the linear ranges were 1 × 10 À 4 -1 × 10 À 2 M, 3 × 10 À 5 -1 × 10 À 3 M and 7 × 10 À 7 -1 × 10 À 4 M with detection limits of 2.42 × 10 À 5 M, 4.58 × 10 À 6 M and 2.38 × 10 À 7 M (S/N = 3), respectively. For simultaneous detection of AA, DA, and UA, the linear response ranges were 1 × 10 À 4 -1 × 10 À 3 M, 3 × 10 À 4 -1 × 10 À 2 M, and 3 × 10 À 6 -1 × 10 À 4 M with detection limits of 6.91 × 10 À 5 M, 3.66 × 10 À 5 M and 4.13 × 10 À 7 M (S/ N = 3), respectively. The GCE/PEDOT/PANI displayed good selectivity, reproducibility and storage stability, and was further applied to the detection of AA, DA, and UA in 5% normal human serum samples.
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