A portable analyzer for pouch-actuated, immunoassay cassettes

Abstract

A portable, small footprint, light, general purpose analyzer (processor) to control the flow in immunoassay cassettes and to facilitate the detection of test results is described. The durable analyzer accepts disposable cassettes that contain pouches and reaction chambers for various unit operations such as hydration of dry reagents, stirring, and incubation. The analyzer includes individually controlled, linear actuators to compress the pouches in the cassette, which facilitates the pumping and mixing of sample and reagents, and to close diaphragm-based valves for flow control. The same types of actuators are used to compress pouches and actuate valves. The analyzer also houses a compact OEM scanner/reader to excite fluorescence and detect emission from labels. The analyzer is hydraulically isolated from the cassette, reducing the possibility of cross-contamination. The analyzer facilitates programmable, automated execution of a sequence of operations such as pumping and valving in a timely fashion, reducing the level of expertise required from the operator and the possibility for errors. The analyzer’s design is modular and expandable to accommodate cassettes of various complexities and additional functionalities. In this paper, the utility of the analyzer has been demonstrated with the execution of a simple, consecutive, lateral flow assay of a model biological system and the test results were detected with up converting phosphor labels that are excited at infrared frequencies and emit in the visible spectrum.

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.…”

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

“…Flow-control (valves) and fluid actuation (pumping) can be realized by on-chip integrated structures and devices, or with off-chip supporting instrumentation such as programmable syringe pumps. Typically, the cassette mates with a portable instrument that may provide regulated heating or cooling, pumping, flow control, reagent delivery, and optical or electrical detection [4][5][6][7]. In contrast, noninstrumented chips operate autonomously, and may include means for manual actuation [8], self-heating such as by chemical reactions [9], thermally activated valves for flow control [10,11], heat-triggered expandable beads for pumping [12], absorption pads for wicking action [13], and on-chip storage of liquids in reservoir compartments and preloaded reagents/enzymes in freeze-dried (lyophilized) form [14,15].…”

Pouch-Chip Immunoassays and Nucleic Acid Amplification Tests

“…Pouch chips have been demonstrated for both immunoassays [11][12][13] and NAATs [6]. Figure 1 shows a pouch chip immunoassay utilizing a conventional lateral flow strip.…”

“…sections of the chip are shown in Figure 3. Pouch chips can be manually operated, i.e., finger actuation of pouches [12], operated with a non-electrical mechanical actuator [11] or electromechanically with solenoid plungers which depress pouches and diaphragm valves [13].…”

“…To summarize, microfluidic chips with integrated pouches and flexible membranes provide on-chip fluid reservoirs and one-shot pumping for fluid actuation, as well as diaphragm valves for flow control and chamber sealing. These POC immunoassay and NAAT chips are compact, self-contained, and easy to use, and can be operated manually, with mechanical spring-wound actuators, or with portable instruments equipped with programmed, electromechanical actuators [6,13].…”