Novel DNA Biosensor for Direct Determination of Carrageenan

Abstract

A novel disposable electrochemical biosensor based on immobilized calf thymus double-stranded DNA (dsDNA) on the carbon-based screen-printed electrode (SPE) is developed for rapid biorecognition of carrageenan by using methylene blue (MB) redox indicator. The biosensor protocol for the detection of carrageenan is based on the concept of competitive binding of positively charged MB to the negatively charged dsDNA and carrageenan. The decrement in the MB cathodic peak current ( i pc ) signal as a result of the released MB from the immobilized dsDNA, and attracted to the carrageenan can be monitored via differential pulse voltammetry (DPV). The biosensor showed high sensitivity and selectivity to carrageenan at low concentration without interference from other polyanions such as alginate, gum arabic and starch. Calibration of the biosensor with carrageenan exhibited an excellent linear dependence from 1–10 mg L −1 (R 2 = 0.98) with a detection limit of 0.08 mg L −1 . The DNA-based carrageenan biosensor showed satisfactory reproducibility with 5.6–6.9% (n = 3) relative standard deviations (RSD), and possessing several advantages such as simplicity, fast and direct application to real sample analysis without any prior extensive sample treatments, particularly for seaweeds and food analyses.

Longer amplicons provide better sensitivity for electrochemical sensing of viral nucleic acid in water samples using PCB electrodes

“…Other researchers have previously reported similar negative impact of salt on MB-DNA interactions and intercalation 33 , 34 . The cation binds with the negative phosphate backbone of DNA thereby hindering the electrostatic interactions between MB and DNA 35 . At higher DNA concentrations, steric inhibition of redox active MB causes reduction in peak current, and therefore electrostatic interactions do not significantly influence the sensor response.…”

Detection of Carrageenan in Cheese Using Lectin Histochemistry

“…Several methods for detecting carrageenan in food have been described in the literature. These include, for example, colorimetric methods [17,48,49]. Soedjak [50] detected carrageenan in milk photometrically with the addition of methylene blue.…”

Considerations on triangular‐shaped electrodes for deoxyribonuclease detection

“…DNA can form various nanoscale structures; recently, many a research has been conducted on biosensors using DNA. [1][2][3] DNA is known to pass electric current under certain conditions, 4 and a number of research groups reported on evaluation of DNA electric characteristics. [5][6][7][8] In addition, a device was proposed to detect deoxyribonuclease (DNase) by measuring impedance change in λDNA stretched and immobilized between opposing triangularshaped electrodes.…”

“…DNA can form various nanoscale structures; recently, many a research has been conducted on biosensors using DNA 1–3 . DNA is known to pass electric current under certain conditions, 4 and a number of research groups reported on evaluation of DNA electric characteristics 5–8 .…”