No abstract

A new electrochemical biosensing strategy has been developed for trace measurements of toxic aromatic amine compounds. The device relies on the intercalative collection of aromatic amines onto the immobilized dsDNA layer followed by potentiometric stripping quantitation of the accumulated species. The enhanced sensitivity, accrued from the DNA collection process, is coupled to new selectivity dimensions provided by the structural requirements for such intercalative binding. The extent and rate of the accumulation are strongly dependent upon the structure of the aromatic amine species. Having the amino substituent in a slightly different position produces a dramatic effect upon the response. Nanomolar detection limits are obtained after a 10-min accumulation. Applicability to river water and groundwater samples is demonstrated. Such DNA-based devices hold great promise for environmental screening of toxic aromatic amines and for elucidating molecular interactions between intercalating pollutants with DNA.

No abstract

No abstract

Peptide nucleic acids (PNA) are new DNA analogs which offer great promise for highly specific DNA biosensors, for use as antisense drugs, or for various molecular biology applications. This article evaluates the interfacial behavior of PNA at carbon paste electrodes, in comparison to DNA. While both PNA and DNA oligomers display a strong adsorption onto the carbon surface, they differ in their interfacial properties due to differences in charge and structure. Factors influencing the adsorption behavior, including the adsorption potential or time, PNA concentration, coexisting anions and cations, or buffer concentration, are explored. The strong adsorption is exploited for an effective preconcentration step prior to the chronopotentiometric measurement. The resulting adsorptive stripping potentiometric protocol offers convenient quantitation of ng/mL levels of PNA, as desired for future diagnostic, pharmaceutical and biological applications of these DNA analogs.