We report a self-contained, miniaturized biochemical assay platform for nucleic acid testing of infectious agents from biological fluids. Our work utilizes a sealed plastic cartridge with patterned surfaces for reagent storage and fluidic processing. Biochemical reactions including nucleic acid amplification tests are performed with a colorimetric readout. Device actuation is automated by a USB controlled servo motor compatible with control via laptop or handheld devices. We describe the fabrication and assembly process for the plastic cartridges, in addition to the workflow for single stream colorimetric nucleic acid amplification assay.
Advantages include:1. Integrated and self-contained device for sample processing, amplification and visual (colorimetric) detection of nucleic acid targets. Reagents are internally contained such that the end user only needs to perform a single loading operation of the sample lysate.
2. Novel device fabrication, which avoids the use of any chemical modification of substrates. Highly amenable to integration with a roll to roll fabrication process and is significantly different from clean room processes described by others.
3. Device actuation via a permanent magnet attached to the rotary arm of a servo motor, whose power requirement is such that it can be powered and controlled by a single USB host device.
4. Isolation of aqueous reagents in fluorinated oil, which serves the twofold purpose of preventing reagent evaporation and establishing fluidic medium which is permeable to magnetic particle plugs but not to the aqueous reagents.
5. Unique assembly and operation of the fluidic cartridge allowing for separation of aqueous reagents via hydrophilic patterns on the upper layer of the device while the bottom layer has a continuous hydrophobic landscape suitable for facile bead plug transport.
6. Integration of fluidic actuation, colorimetric signal acquisition and processing on a single mobile device serving as a USB host device.
Patent Status: Granted US Patent
9,463,461
