The separation and enrichment of bio-particles is a most common need in bioanalytical applications, from diagnostics, food safety to pharmaceutics. Bio-particles include nucleic acids, proteins, cellular vesicles (e.g. exosomes), viruses and bacteria. Current technologies such as filtering, liquid chromatography or electrophoresis can separate bio-particles based on their size or electrical charges, but are difficult to integrate in small point of care devices due to cumbersome instrument or device size, complex (manual) operations or the need of intensive preprocessing. The difficulty of bio-particle separation is becoming a major bottleneck that prevents many microfluidic techniques from being widely used in practical applications. The focus of this PhD is to develop electro-capturing techniques and devices to separate and enrich biomolecules in microfluidic format.
The electrical properties of bio-particles, such as charge or dielectric constant, allow the bio-particles to be effectively manipulated by the electrostatic force in an electric field. Electrical bio-particle manipulation provides many advantages over competing techniques such as high bio-specificity, simple structure, low cost fabrication, programmable operations, etc. Prior art has demonstrated capturing human cells in complex background such as blood. The same physical principles are also promising for bio-particle capture, however, with new challenges. Since bio-particles are much smaller than cells, the electrostatic forces scale down with bio-particle size and have to compete with other effects that are not ignorable, such as electrothermal flow, electroosmosis and Brownian motion. A most promising solution to address the challenge is downsizing the electrode dimensions & spacing to greatly improve the electric field and field gradient, hence stronger electrostatic force. The electrical property of bio-particles and the consequential determination of the electrode geometry, material and operation parameters will be studied in this PhD topic. Other key aspects will be the understanding and control of the parasitic forces acting on the particles, and control of their fluidic environment such as flow or properties of the buffer. Devices with electrode arrays and dedicated microfluidic structures will be designed and fabricated in imec’s cleanroom. The devices will be characterized and used for bio-particle capture measurements. This topic will be supervised and supported by multiple physicists, biochemists and engineers in the imec life science department.
Type of work:
10% literature study, 20% theoretical modelling, 20% device fabrication, 40% laboratory measurement, 10% publication, conferences and other activities .
Supervisor: Liesbet Lagae
Daily advisor: Chengxun Liu
When you apply for this PhD project, mention the following reference code in the imec application form: ref. SE 1704-06.