MICROFLUIDIC MOLECULAR AND CELLULAR DETECTION OF MALARIA TOWARDS ELIMINATION
Open Access
- Author:
- Choi, Gihoon
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 12, 2020
- Committee Members:
- Weihua Guan, Dissertation Advisor/Co-Advisor
Weihua Guan, Committee Chair/Co-Chair
Aida Ebrahimi, Committee Member
Zhiwen Liu, Committee Member
Pak Kin Wong, Outside Member
Kultegin Aydin, Program Head/Chair - Keywords:
- Point-of-care
Malaria
Resistive pulse sensor
time-division multiple access
multiplexed
Nucleic acid tests
Lab-on-a-disc
Microfluidics
cell deformability
parasitemia quantification
Deformability-activated sorting
time-division multiple access - Abstract:
- Malaria is a mosquito-borne disease caused by Plasmodium parasites, predominately in resource-limiting areas. With the significant progress in malaria controls during the past decade, WHO endorsed the ambitious goal of achieving malaria elimination. Since low-level malaria infection is highly distributed in the elimination-phase countries, the elimination strategy involves (1) identification of asymptomatic carriers to reduce the parasite reservoir and (2) interruption of the malaria transmission vector. The work presents the microfluidic tools that facilitate point-of-care nucleic acid testing (NAT) and cell mechanotyping (i.e., label-free cell deformability sensor and deformability-activated cell sorting) towards the malaria elimination. While point-of-care NAT opens up extensive remote diagnostic opportunities in resource-limited regions, cell mechanotyping can be used to explore the underlying mechanism of the transmission vector. The thesis will describe the single- and quad-plex point-of-care NAT systems, which deliver highly sensitive molecular answers within 40 minutes from raw whole blood samples. Scalable parasite DNA sample preparation and subsequent real-time loop-mediate isothermal amplification (LAMP) were seamlessly integrated on a single microfluidic reagent compact disc. The combination of the sensitivity, specificity, cost, and scalable sample preparation suggests effective and accurate malaria screening in the field. To provide tools for a microfluidic cell mechanotyping study, we developed a constriction-based cell deformability sensor. Cell deformability is an excellent label-free biomarker for cell abnormalities. The sensor indirectly measures the cell deformability by probing the transit time during cell translocation events at micro-constriction. We successfully evaluated the sensor performance by achieving the high-throughput parasitemia measurement and parasite stage determination and demonstrated cell deformability is an excellent label-free biomarker for malaria infection. Using this biophysical marker, we demonstrated a single-cell-resolved, cytometry-like deformability-activated cell sorting in the continuous flow to enrich the gametocytes from the crude blood samples. Finally, we demonstrated the constriction-based multichannel resistive pulse sensor, integrated with time-division multiplexing accessing (TDMA) methodology to further improve deformability measurement and deformability-activated sorting throughput with maintaining the scalability. We envision that point-of-care NAT and microfluidic cell mechanotyping devices will provide early and accurate malaria screening in the field and in-depth of understanding of overall malaria pathophysiology and underlying mechanism of the malaria transmission vector.