PAMAM Dendrimers‐Based DNA Biosensors for Electrochemical Detection of DNA Hybridization

Abstract

Gold electrodes were modified with submonolayers of mercaptoacetic acid (RSH) and further reacted with poly(amidoamine) (PAMAM) dendrimers (generation 4.0) to obtain thin films, on which DNA probe was later immobilized to afford a stable recognition layers. The characterization of the PAMAM/RSH-modified electrode was investigated by cyclic voltammetry (CV) and electrochemical impedance measurement. Differential pulse voltammogram (DPV) measurement was used to monitor DNA hybridization with daunomycin (DNR) as indicator. Experiments carried out with these novel materials not only showed an improved DNA attachment quantity on the dendrimers-modified electrodes compared to DNA sensors with oligonucleotides directly immobilized on Au electrodes, but also exhibited a high selectivity, sensitivity and stability for the measurement of DNA hybridization.

Biosensor Based on Self‐Assembling Glucose Oxidase and Dendrimer‐Encapsulated Pt Nanoparticles on Carbon Nanotubes for Glucose Detection

“…CNT-based glucose electrochemical sensor and biosensors took a significant role of monitoring blood glucose [9 -11] through direct adsorption of glucose oxidase on carbon nanotubes [12] or entrapment of glucose oxidase into the ultrathin polypyrrole film by electrochemical methods [13]. In addition, the attachment of biological molecules or metal nanoparticles onto carbon nanotubes has received significant interest, particularly for application in biosensor, resulted in improving electroactivity of biosensors [14]. The deposition of platinum nanoparticles onto Nafioncontaining CNT/GOx film led to higher sensitivity compared to devices based on CNT or Pt-particles alone [4,15].…”

Detection of Sequence-Specific Gene by Multi-Channel Electrochemical DNA Chips

“…Using potassium ferricyanide as electrochemical indicator, the device could be used to recognize reliably not only synthetic sequence-specific DNA but also LAMP products. Though the detection limit of target DNA is larger than that obtained at solo DNA sensor as outlined in the references, [7][8][9][10]32 this can be developed by using some special indicators, such as Hoechst 33258, 4,33 [Ru(NH 3 ) 6 ] 3+ 20 and so on. In fact in this study we focus on many other attractive advantages of the electrochemical chip.…”

“…5,6 Therefore, a lot of achievements have been obtained in the detection of DNA by electrochemical methods. 5,[7][8][9][10][11][12][13] Over the past years, our research groups have also focused on the development of electrochemical DNA hybridization biosensors.…”

Kinetic studies of HRP adsorption on ds-DNA immobilized on gold electrode surface by EIS and SPR

“…After this step, the adsorption of PAMAM, the positively charged polymer molecule, was performed. The surface becomes positive and would attract the negative charges of Fe(CN) 6 3-/4-decreasing the R ct values, 27 according to Table 1. When the surface is sequentially modified with ds-DNA there is an increase in the R ct values because they generate an insulating layer on the modified surface, which makes the electron transfer more difficult.…”

“…23,24 In previous works, the formation of PAMAM and PAMAM/ds-DNA layer on gold surface was investigated. [25][26][27] Biological compounds including DNA, RNA, enzymes and proteins can be regarded as natural charged functional polymers. They are also widely used in the layer-by-layer multilayer formation.…”