الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
In this work, our idea depends simply on tethering of a chemoreceptor(protamine sulfate or antithrombin III) on the microfluidic channel surface,
followed by an electrostatic interaction between heparin and its antidote or its
physiological partner respectively.
Streaming potential is the detection principle of this work, where the
magnitude of ΔE is directly proportional to the surface charge. The change in
charge, in turn; {complete inversion in the best case scenario} is dependent on
the [analyte].
The detection process described herein is fairly quick, where each data point
in any calibration curve takes no longer than 14 seconds.
AN OVERVIEW
As we mentioned before, precise and quick monitoring of blood heparin
concentrations helps in controlling heparin therapy by finding the minimal
protamine dose required to neutralize the anticoagulant activity of heparin at
the end of “Cardio Pulmonary Bypass” (CPB). This is of clinical significance
since protamine overdose is known to cause serious complications and other
toxic effects.
Unfortunately, current assay methods often fail to provide the desired
quantitative measurement or automation. Therefore, this created a need to build
a heparin sensor that overcomes the dependency on antithrombin III, other
factors and assay reagents, and at the same time minimizes the gap between in
vivo and in vitro heparin assays.
In order to set up more direct assay procedures, it is necessary to consider
whether the structure and functional components of heparin offer any
possibility for transduction. Electrostatic interaction between a suitable cationic
affinity ligand and heparin appears to be the “number one” choice; since it
would revoke the reliance on heparin activity and also accommodate the
variation in molecular weight, assuming that the charged functional groups are
evenly distributed across the molecule. Identification of this cationic ligand or
surface to ”recognize” heparin is critical to the potential success of a direct
assay. Both neutral and synthetic candidates could be considered.
Herein we describe a label-free detection method of several probes using
pulsed streaming potentials in plastic microfluidic channels built with the
commodity thermoplastic Cyclic Olefin Copolymer (COC) and implying two
cationic ligands; protamine sulfate and antithrombin III