Mobile Platform for Multiplexed Detection and Differentiation of Disease-Specific Nucleic Acid Sequences, Using Microfluidic Loop-Mediated Isothermal Amplification and Smartphone Detection (Collaboration, ongoing)
In a collaboration with University of Illinois, Dr. David Hirschberg contributed significantly to a recent publication in Analytical Chemistry involving the application of Loop-mediated isothermal amplification (LAMP) to perform point-of-care diagnostics using a microfluidic chip. His role was the development of the LAMP assay for equine pathogen detection.
New tools are needed to enable rapid detection, identification, and reporting of infectious viral and microbial pathogens in a wide variety of point-of-care applications that impact human and animal health. We report the design, construction, and characterization of a platform for multiplexed analysis of disease-specific DNA sequences that utilizes a smartphone camera as the sensor in conjunction with a hand-held cradle that interfaces the phone with a silicon-based microfluidic chip embedded within a credit-card-sized cartridge. Utilizing specific nucleic acid sequences for four equine respiratory pathogens as representative examples, we demonstrated the ability of the system to utilize a single 15 μL droplet of test sample to perform selective positive/negative determination of target sequences, including integrated experimental controls, in approximately 30 min. Our approach utilizes loop-mediated isothermal amplification (LAMP) reagents predeposited into distinct lanes of the microfluidic chip, which when exposed to target nucleic acid sequences from the test sample, generates fluorescent products that when excited by appropriately selected light emitting diodes (LEDs), are visualized and automatically analyzed by a software application running on the smartphone microprocessor. The system achieves detection limits comparable to those obtained by laboratory-based methods and instruments. Assay information is combined with the information from the cartridge and the patient to populate a cloud-based database for epidemiological reporting of test results.