(1343-D) Microfluidic Innovations to Enable Automated Nucleic Acid Detection in the Field

Abstract: Sensitive and multiplexed detection of nucleic acid targets from biological samples is a challenging problem which is typically addressed using specialized equipment in a laboratory setting. The process involves several key steps including sample collection, sample lysis, nucleic acid extraction, nucleic acid detection, and signal readout. Each of these steps is often achieved using separate pieces of equipment, specialized processing kits, or a sequence of manual steps which require user intervention. For these reasons, the existing process is not suitable for in-field use. To address this need, Draper is developing a fieldable sample-to-answer system for nucleic acid detection.

Here, we highlight two innovations which we have incorporated into our fieldable system, comprising a durable device and an integrated disposable cartridge. The first innovation is the integration and optimization of a nucleic acid extraction column in a microfluidic network to provide high nucleic acid extraction yield. The system can isolate total nucleic acid (RNA and DNA) from several sample types, including bronchoalveolar lavage (BAL) fluid and nasopharyngeal (NP) swabs. The system operates in an automated fashion to carry out the extraction. The purified sample is viable for use in downstream nucleic acid quantification and detection assays. The second innovation we highlight is a unique approach to microfluidic mixing which enhances the transport of extracted nucleic acids to improve the likelihood of detection. The approach leverages a small vibration motor to drive oscillatory motion of one wall of a closed fluid chamber which leads to agitation of the enclosed fluid. The chamber geometry was optimized to maximize the mixing and small air-filled cavities were added for even further enhancement.

The system being developed, which incorporates the previously described microfluidic innovations, is an advancement towards sample-to-answer detection of nucleic acid targets that can be performed in the field. It is comprised of a durable device as well as a disposable microfluidic cartridge containing a reagent storage module that can be stored separately, if needed. The system is battery-operated and will be ruggedized making it a feasible for in-field use. The durable component contains fluidic, electronic, and software controls creating an automated system that requires minimal user intervention. This automated, fieldable system reduces the need for several specialized pieces of equipment and a sophisticated laboratory setting and enables total nucleic acid extraction and detection in the field.