A portable, integrated analyzer for microfluidic – based molecular analysis

Abstract

A portable, fully automated analyzer that provides actuation and flow control to a disposable, self-contained, microfluidic cassette ("chip") for point-of-care, molecular testing is described. The analyzer provides mechanical actuation to compress pouches that pump liquids in the cassette, to open and close diaphragm valves for flow control, and to induce vibrations that enhance stirring. The analyzer also provides thermal actuation for the temperature cycling needed for polymerase chain reaction (PCR) amplification of nucleic acids and for various drying processes. To improve the temperature uniformity of the PCR chamber, the system utilizes a double-sided heating/cooling scheme with a custom feedforward, variable, structural proportional-integral-derivative (FVSPID) controller. The analyzer includes a programmable central processing unit that directs the sequence and timing of the various operations and that is interfaced with a computer. The disposable cassette receives a sample, and it carries out cell lysis, nucleic acid isolation, concentration, and purification, thermal cycling, and either real time or lateral flow (LF) based detection. The system's operation was demonstrated by processing saliva samples spiked with B. cereus cells. The amplicons were detected with a lateral flow assay using upconverting phosphor reporter particles. This system is particularly suited for use in regions lacking centralized laboratory facilities and skilled personnel.

Characterization and analysis of real-time capillary convective PCR toward commercialization

“…The capillary tube reactor is made of polycarbonate by injection molding for low-cost, smooth surface finishes for low binding of reactants, biocompatibility, low autofluorescence, and high optical transparency in the fluorescence wavelength ranges. [27][28][29][30] In most of the reported CCPCR, instruments with a single-end heating strategy have been adopted to heat the capillary tube from the bottom to introduce thermal convection. It has been demonstrated that satisfactory convective amplification can be achieved with the dual-end heating strategy when additional heating from the top of the capillary tube is incorporated.…”

Upconverting Phosphor Labels for Bioanalytical Assays

“…The system is constructed on a disposable, self-contained microfluidic cassette comprising all reagents for upstream sample pretreatment and an LF strip for multiplexed analysis of the processed sample. All operations are carried out automatically by the analyzer [155][156][157], and the result is obtained in less than 1 h, which sets strict time limits on each step [158]. Different versions of portable analyzers (manual, mechanical, or thermal actuations) with external LF strip scanner have been described [158][159][160].…”

Microfluidic “Pouch” Chips for Immunoassays and Nucleic Acid Amplification Tests

“…The microfluidic format in the chip described here integrates and automates the consecutive flow steps in a selfcontained device with pre-stored buffers and reagents. [17], (c) computer-controlled device for automated actuation of pouch cassettes [6] Prior to use, the chip is in two parts: (1) a top storage component with air-filled pouches, sealed reagents, metering chamber and needle seats; and (2) a bottom processing component with connection needles, mixing chamber, and detection chamber. Subsequent to sample loading, the chips are mated wherein needles of the bottom component pierce a sealing film of the top layer, making fluidic connections between microfluidic channels in both parts.…”

“…The sample loading, washing, and elution are effected with pouch actuation that discharges liquid and the aid of a small vacuum pump on the companion instrument. Instrumentation platforms to operate these chips are further described by Qiu et al (see Note 1) [6,7].…”