Finger-actuated, self-contained immunoassay cassettes

Abstract

The building blocks for an inexpensive, disposable, luminescence-based microfluidic immunoassay cassette are described, and their integration in a point-of-care diagnostic system is demonstrated. Fluid motion in the cassette is driven by depressing finger-actuated pouches. All reagents needed for the immunoassay can be stored in the cassette in liquid form. Prior to use, the cassette consists of two separate parts. A top storage component contains pouches, sealed storage chambers, a metering chamber, and needle seats. The bottom processing component contains connection needles, a mixing chamber, and a detection chamber with immobilized proteins. Subsequent to sample introduction, the storage and processing components are mated. The needles form hydraulic connections between the two parts and, in some cases, close valves. The pouches are then actuated sequentially to induce flow of various reagents and facilitate process operations. The cassette is compatible with different detection modalities. Both a cassette with immunochromatographic-based detection and a cassette with microbead-based detection were constructed and evaluated. The immunochromatographic cassette was used to detect antibodies to HIV in saliva samples. The bead-based cassette was used to detect the proinflammatory chemokine IL-8. The experimental data demonstrates good repeatability and reasonable sensitivity.

Towards autonomous lab-on-a-chip devices for cell phone biosensing

“…The principles for autonomous operations have been investigated independently of cell phone detection and entail the integration of multiple functions (Abgrall and Gué, 2007;Ahn et al, 2004;Qiu et al, 2009;Bharadwaj and Singh, 2013;Floiris et al, 2010;Sin et al, 2011). Figure 1 illustrates an idealized device with all the stages that would be necessary in an end-to-end disposable solution for cell phone readout.…”

“…Finger-powered microfluidics (Iwai et al, 2014;Begolo et al, 2014;Comina et al, 2015a;Qiu et al, 2009) systems are another possibility for integrating a pressure source for autonomous disposables. These systems attempt to overcome some of the limitations of capillary systems, such as small forces and slow responses, besides that capillary systems are limited to sample volumes smaller than the internal volume of the device (Begolo et al, 2014).…”

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].…”

A “place n play” modular pump for portable microfluidic applications

“…Aimed at avoiding expensive and nondisposable active microfluidic pumps, several researchers have proposed some interesting portable pumping mechanisms, such as droplet-based passive pumping, 19 evaporation, [20][21][22] capillary flow, 23,24 gravity-driven flow, 25,26 and fingeractuated pumping. 27,28 These developed portable micropumps scale rather favorably in microfluidics while preserving simplicity. However, they make the systems either complex to fabricate or difficult to provide precise and complicated fluidic control.…”