Journal: Biosensors

Article Title: Recent Uses of Paper Microfluidics in Isothermal Nucleic Acid Amplification Tests

doi: 10.3390/bios13090885

Figure Lengend Snippet: Fully integrated systems with LAMP, EXPAR, and RPA. The fully integrated LAMP ( top left ) comprises three steps, starting with the injection of fluids to the capture membrane and subsequent absorption via wicking (A). Then, the disk rotates and undergoes an elution process before the disk counter-rotates, which induces PCR sealing, amplification, and readout (B). Another LAMP microfluidic device ( top right ) is also pictured, interfaced with a temperature controller and power supply. The third fully integrated LAMP device ( middle left ) combines DNA extraction, purification, amplification, and detection in a microdevice. The bacteria sample is loaded and captured on an FTA card before being introduced to the LAMP reagent chamber, where the DNA target is mixed with the LAMP reagents stored on the disc. After heating the microdevice, the sealant film is removed, and colorimetric detection agents are added. Another fully integrated LAMP system ( middle right ) detects SARS-CoV-2 genes from wastewater samples based on CRISPR/Cas12a-contained base pairs of gRNAs. Fluorescence detection is conducted with probe recognition. EXPAR and LAMP are demonstrated in a fully integrated system ( bottom left ), incorporating a sensor cartridge with a thin-film heater and a thermoelectric cooler for amplification (a). The cartridge layers are expanded to show the individual layers wit channels, chambers, microfiber pads, and analysis chips (b). The heater heats the lysis chamber, which evaporates and absorbs into the paper strip moving to the reaction chamber. The sample is collected on cellulose, where the microfiber filter pad reduces the fluorescence signal. RPA with nucleic acid enrichment on the LFIA strip ( bottom right ) is shown to extract the nucleic acids onto an FTA card (b). The amplification chip is loaded with the FTA card, primers, probes, and RPA reagents and incubated at 40 °C for 20 min (c). The results were observed under 488 nm blue light excitation once the chip was placed into the detection chamber (d). The portable reader visualizes the fluorescence results compatible with smartphone applications. Reprinted from [ , ] under Creative Commons Attribution License. Reprinted with permissions from , Copyright 2022 Elsevier; , Copyright 2022 American Chemical Society; and , Copyright 2023 Elsevier. Reprinted from under Creative Commons Attribution License.

Article Snippet: This extraction method has been utilized to detect Magnaporthe oryzae , GMO, Toxoplasma gondii , and various potato viruses, including potato leafroll virus and potato virus S. Another example is where the target was extracted via a Whatman grade GF/F glass microfiber filter embedded in a paper chip.

Techniques: Injection, Membrane, Amplification, DNA Extraction, Purification, Bacteria, CRISPR, Fluorescence, Lysis, Stripping Membranes, Incubation