Label‐Free Photoelectrochemical Detection of Double‐Stranded HIV DNA by Means of a Metallointercalator‐Functionalized Electrogenerated Polymer

Abstract

The design of photoactive functionalized electrodes for the sensitive transduction of double-stranded DNA hybridization is reported. Multifunctional complex [Ru(bpy-pyrrole)2 (dppn)](2+) (bpy-pyrrole=4-methyl-4'-butylpyrrole-2,2'-bipyridine, dppn=benzo[i]dipyrido[3,2-a:2',3'-c]phenazine) exhibiting photosensitive, DNA-intercalating, and electropolymerizable properties was synthesized and characterized. The pyrrole groups undergo oxidative electropolymerization on planar electrodes forming a metallopolymer layer on the electrode. Thanks to the photoelectrochemical and intercalating properties of the immobilized Ru(II) complex, the binding of a double-stranded HIV DNA target was photoelectrochemically detected on planar electrodes. Photocurrent generation through visible irradiation was correlated to the interaction between double-stranded DNA and the metallointercalator polymer. These interactions were well fitted by using a Langmuir isotherm, which allowed a dissociation constant of 2×10(6) L mol(-1) to be estimated. The low detection limit of 1 fmol L(-1) and sensitivity of 0.01 units per decade demonstrate excellent suitability of these modified electrodes for detection of duplex DNA.

Advances in nanomaterials and their applications in point of care (POC) devices for the diagnosis of infectious diseases

“…After the two DNA strands get detached, these duplexintercalating entities are freed, hence generating ECM signals. The latter strategy has been adopted in the investigation of infectious pathogens such as Escherichia Coli, Mycobacterium tuberculosis, HIV (Haddache et al, 2014), and HBV (Meric et al, 2002). However, a grave downside of this technique is the interaction between the chemicals and DNA duplex, which makes them potentially mutagenic (Watanabe et al, 2015).…”

CdS/MoS 2 heterojunction-based photoelectrochemical DNA biosensor via enhanced chemiluminescence excitation

“…Photoelectrochemical DNA bioassays have attracted widespread attention in analytical community owing to its low background signal and excellent sensitivity (Haddache et al, 2014;Zhao et al, 2014). The considerable efforts have been developed to design photoelectrochemical platform based on various nanomaterials such as metal oxide (Lu et al, 2006;Wu et al, 2013), two-dimensional nanosheets (Zhuang et al, 2015), metal nanoparticles Lu et al, 2008), quantum dots (QDs) (Long et al, 2011) and their nanohybrids (Zhang et al, 2012).…”

The laccase mediator system at carbon nanotubes for anthracene oxidation and femtomolar electrochemical biosensing

“…No accurate model was obtained using a simple Langmuir isotherm, likely arising from the presence of a mixture of enzymes, anthracene and anthraquinone at MWCNT electrodes. In this particular case where heterogeneity of adsorptions might be caused by a complicated mixture at such porous surface, the Freundlich model was successfully used to fit the experimental data, according to eqn (2): 38,43 where I p,eq is the equilibrium peak current, I p,max is the peak current at saturating concentrations of anthracene and K AQ is the association constant between the as-produced anthraquinone (AQ) derivative and the MWCNT surface in water and n is Langmuir–Freundlich coefficient number. Table 1 shows the Langmuir–Freundlich model parameters obtained from fitting curves of Fig.…”