Improved electrochemical performances of polyaniline nanotubes-poly-L-lysine composite for label-free impedance detection of DNA hybridization

Abstract

A sensitive label-free DNA hybridization biosensing platform was fabricated based on the synergistic effect of polyaniline nanotubes (PANI nt ) and poly-L-lysine (pLys). The composite of pLys and PANI nt was coated onto the carbon paste electrode (CPE) to form a uniform and very stable nanocomposite membrane. The pLys in the composite film not only acts as a membrane to retain good electron transfer capability of PANI nt even at physiological pH, but also possesses fine biocompatibility for bio-analytes. DNA probes with negatively charged phosphate groups were readily linked to the positively charged pLys surface due to the strong electrostatic affinity. The synergistic effect of PANI nt and pLys could significantly enhance the sensitivity of DNA hybridization recognition. The phosphinothricin acetyltransferase (PAT) gene fragment from transgenic corn and the polymerase chain reaction amplification of the terminator of nopaline synthase gene from the real sample of a kind of transgenic soybean were detected by this DNA electrochemical biosensor via label-free impedance method. This stable composite gives convenient permselectivity properties as a transducer material for the design of modern electrochemical impedance biosensor using [Fe(CN) 6 ] 3/4 as an indicator.

One‐Dimensional Nanostructured Polyaniline: Syntheses, Morphology Controlling, Formation Mechanisms, New Features, and Applications

“…In addition to the research studies for various gases, 1D nano‐PANI was also studied for biosensors, either as labels or as transducers 354–361. PANI nanofibers or nanotubes are prominent candidates for supports in enzyme immobilization and biosensors because of, on the one hand, several advantages including the excellent matrix for immobilization of biomolecules and rapid electron transfer for signals,362–365 and two redox couples in the right potential range that facilitate the enzyme–polymer charge transfer366 demonstrated by PANI; on the other hand, the large surface area and nanopores of PANI nanofibers or nanotubes into which enzymes and other target species can be immobilized 367–369.…”