Institute of Biomaterials and Biomedical Engineering

Student’s Name: Alphonsus Ng
Supervisor: Dr. Aaron Wheeler
PhD Thesis: Development of Digital Microfluidic Heterogeneous Immunoassays

The increasing demand for immunoassays in clinical diagnostics have necessitated the use of robotics to alleviate the tedium of labour-intensive liquid handling. Unfortunately, robotic liquid handlers are only feasible in centralized facilities as they require high capital costs, bulky instrumentation, large volumes of reagents, and skilled technicians for maintenance and operation.

Alphonsus’ research has been focused on miniaturizing immunoassays onto chips no bigger than a credit card. This will eventually pave the way for decentralized immunodiagnostics capable of providing fast, quantitative results in the clinic or at the bedside. The availability of such tools can enable early diagnosis, limit outbreaks, decrease hospital stays, and eliminate transportation and administrative expenses.

The immunoassay chips are powered by a fluid handling technology called digital microfluidics, in which liquid is electrostatically manipulated in terms of small droplets on an array of electrodes. By applying an appropriate sequence of voltage to these electrodes, software-programmable operations can be performed on individual droplets, including move, merge, mix, split, and dispense from reservoirs. This configuration enables parallel processing of multiple droplets, where each droplet corresponds to a single test tube in a standard laboratory assay.

Alphonsus’ research was supported by NSERC Alexander Graham Bell Canada Graduate Scholarship (M+D3). His work has been published in journals such as Nature Communications, Clinical Chemistry, and Analytical Chemistry, and he was awarded the 2014 Donnelly Centre Thesis Prize.

With the support of Grand Challenges Canada, he is currently a postdoctoral fellow at the University of Toronto working on pilot testing the immunoassay chips in Vietnam. In the future, he wants to continue to develop small biomedical instrumentation with big impact.