Picogram quantitation of total DNA using DNA-binding proteins in a silicon sensor-based system

Electrochecmical biosensors for DNA sequence detection

“…The authors do not state whether the inhibition mechanism involves competition for the DNA-binding proteins (a situation where increased reagent concentrations would eradicate the problem) or competition of short streptavidinlabelled DNA fragments (too short to bind to the anti-DNAurease conjugate) for biotinylated sites on the membrane. The authors report that DNA 872 bases long is quantitatively bound, and a detection limit of 2pg was reported for calf thymus DNA [25].…”

“…Two DNA biosensors using potentiometric transduction have been reported by this group: one is designed to quantitate total DNA [25], while the second is designed for sequence-selective detection of PCR products [24]. Both rely on the capture of biotinylated species onto streptavidin-coated membranes, and the detection of a local pH change produced at the membranecovered sensor surface by an enzyme label (urease).…”

“…The total DNA sensor [25] allows binding between a thermally-denatured DNA sample, biotin-labelled singlestranded DNA binding protein, a monoclonal anti-DNAurease conjugate, and streptavidin to occur in homogeneous solution. Streptavidin is a tetrameric protein, with four biotinbinding sites per molecule.…”

Current strategies for electrochemical detection of DNA with solid electrodes

“…Occasionally roles are reversed -the analyte is immobilised and the probe is in solution [75,76,77,78,79]. The second format is the "sandwich-type" assay, socalled because the target sequence is hybridised both with the immobilised probe and, in another region, with a second probe (reporter probe), which is commonly labelled for detection [43,46,50,52,56,80,81,82,83,84,85,86,87]. Hybridisation between target and reporter probe is sometimes performed in solution; this hybrid is then allowed to hybridise with the immobilised probe [56,84].…”

Process analytics for purification of monoclonal antibodies

“…The main alternative has been a method based on DNA binding proteins (e.g. Threshold system [18]). The DNA hybridisation method provided adequate sensitivity, however was subjected to lengthy analysis time, issues with robustness and low precision.…”