Microfluidic tectonics platform: A colorimetric, disposable botulinum toxin enzyme‐linked immunosorbent assay system

Abstract

A fabrication platform for realizing integrated microfluidic devices is discussed. The platform allows for creating specific microsystems for multistep assays in an ad hoc manner as the components that perform the assay steps can be created at any location inside the device via in situ fabrication. The platform was utilized to create a prototype microsystem for detecting botulinum neurotoxin directly from whole blood. Process steps such as sample preparation by filtration, mixing and incubation with reagents was carried out on the device. Various microfluidic components such as channel network, valves and porous filter were fabricated from prepolymer mixture consisting of monomer, cross-linker and a photoinitiator. For detection of the toxoid, biotinylated antibodies were immobilized on streptavidin-functionalized agarose gel beads. The gel beads were introduced into the device and were used as readouts. Enzymatic reaction between alkaline phosphatase (on secondary antibody) and substrate produced an insoluble, colored precipitate that coated the beads thus making the readout visible to the naked eye. Clinically relevant amounts of the toxin can be detected from whole blood using the portable enzyme-linked immunosorbent assay (ELISA) system. Multiple layers can be realized for effective space utilization and creating a three-dimensional (3-D) chaotic mixer. In addition, external materials such as membranes can be incorporated into the device as components. Individual components that were necessary to perform these steps were characterized, and their mutual compatibility is also discussed.

Sensing the Deadliest Toxin: Technologies for Botulinum Neurotoxin Detection

“…Indeed, detection of BoNT on microfluidic chips has been developed [134,135,136]. Assays carried out on a chip are miniaturized versions of the macroscopic assays described above, such as the sandwich type immunoassay [136] or FRET based endopeptidase assay [134,135]. There are clear advantages to microfluidic technology, including a reduction of reagent consumption and the ability to operate in a semiautomatic mode for all steps (e.g., sample preparation, pretreatment, mixing, incubation, washing) carried out on a chip.…”

Effects of polymers on the properties of hydrogels constructed using sodium deoxycholate and amino acid

“…16 Bile acids and their salts belong to not only important biological surfactants, but also small-molecule biological gelators that can act as solubilizers of cholesterol, bilirubin, and various fat-soluble vitamins in the intestine of vertebrates, including humans. 17,18 Unlike the typical surfactant that carries a polar head and a nonpolar tail, the bile salt is well known as a facial amphiphile and possesses a rigid steroid backbone comprising hydroxyl groups and a carboxyl groups on the polar face and methyl groups on the nonpolar face.…”

Centrifugal Microfluidic Integrated Optical System for Sensing Pesticide Residues

“…The capillary forces are utilized to control the flow sequence of different reaction [21,22]. The pumping pressure of fluid generated by centrifugal force is expressed as Eq.…”