Abstract
A novel label-free photoelectrochemical biosensing method for highly sensitive and specific detection of DNA hybridization using a CdS quantum dot (QD)-dendrimer nanocomposite is presented. A molecular beacon (MB) was assembled on a gold-nanoparticle-modified indium tin oxide electrode surface. Hybridization to a complementary target DNA disrupts the stem-loop structure of the MB, which was afterward labeled with the QD-dendrimer nanocomposite. The modified indium tin oxide electrode showed a stable anodic photocurrent response at 300 mV (vs Ag/AgCl) to light excitation at 410 nm in the presence of 0.1 M ascorbic acid as an electron donor. The protocol developed integrates the specificity of an MB for molecular recognition and the advantages of gold nanoparticles for increasing the loading capacity of the MB on the electrode surface and accelerating the electron transfer. Moreover, the photocurrent was greatly enhanced because of the high loading of QDs by the dendrimer, which eliminated the surface defects of CdS QDs and prevented recombination of their photogenerated electron-hole pairs. Under the optimal conditions, a linear relationship between the increase of photocurrent and target DNA concentration was obtained in the range from 1 fM to 0.1 nM, with a detection limit of 0.5 fM. The sequence-specificity experiment showed that one or three mismatches of DNA bases could be discriminated. This photoelectrochemical method is a prospective technique for DNA hybridization detection because of its great advantages: label-free, high sensitivity and specificity, low cost, and easy fabrication. This could create a new platform for the application of CdS QD-dendrimer nanocomposites in photoelectrochemical bioanalysis. Graphical abstract.
TY - JOUR
T1 - A label-free photoelectrochemical DNA biosensor using a quantum dot-dendrimer nanocomposite.
A1 - Divsar,Faten,
Y1 - 2019/08/10/
PY - 2019/06/03/received
PY - 2019/07/30/accepted
PY - 2019/07/16/revised
PY - 2019/8/12/pubmed
PY - 2019/11/28/medline
PY - 2019/8/12/entrez
KW - Nanocomposites
KW - Photoelectrochemical biosensor
KW - Poly(amidoamine) dendrimer
KW - Quantum dots
SP - 6867
EP - 6875
JF - Analytical and bioanalytical chemistry
JO - Anal Bioanal Chem
VL - 411
IS - 26
N2 - A novel label-free photoelectrochemical biosensing method for highly sensitive and specific detection of DNA hybridization using a CdS quantum dot (QD)-dendrimer nanocomposite is presented. A molecular beacon (MB) was assembled on a gold-nanoparticle-modified indium tin oxide electrode surface. Hybridization to a complementary target DNA disrupts the stem-loop structure of the MB, which was afterward labeled with the QD-dendrimer nanocomposite. The modified indium tin oxide electrode showed a stable anodic photocurrent response at 300 mV (vs Ag/AgCl) to light excitation at 410 nm in the presence of 0.1 M ascorbic acid as an electron donor. The protocol developed integrates the specificity of an MB for molecular recognition and the advantages of gold nanoparticles for increasing the loading capacity of the MB on the electrode surface and accelerating the electron transfer. Moreover, the photocurrent was greatly enhanced because of the high loading of QDs by the dendrimer, which eliminated the surface defects of CdS QDs and prevented recombination of their photogenerated electron-hole pairs. Under the optimal conditions, a linear relationship between the increase of photocurrent and target DNA concentration was obtained in the range from 1 fM to 0.1 nM, with a detection limit of 0.5 fM. The sequence-specificity experiment showed that one or three mismatches of DNA bases could be discriminated. This photoelectrochemical method is a prospective technique for DNA hybridization detection because of its great advantages: label-free, high sensitivity and specificity, low cost, and easy fabrication. This could create a new platform for the application of CdS QD-dendrimer nanocomposites in photoelectrochemical bioanalysis. Graphical abstract.
SN - 1618-2650
UR - https://www.unboundmedicine.com/medline/citation/31401669/A_label_free_photoelectrochemical_DNA_biosensor_using_a_quantum_dot_dendrimer_nanocomposite_
DB - PRIME
DP - Unbound Medicine
ER -
