Microfluidics with fluid walls

Thesis

A high variety of microfluidic platforms that aim to miniaturize and automate biomedical assays have been developed in the last decades, but these have failed to be integrated as common equipment in laboratories. This is due to concerns about biocompatibility, issues about the ease of use and the limited range of readouts that the system can accommodate.

This thesis describes a powerful and versatile alternative to conventional microfluidics, in which solid, obscuring walls are replaced by morphing fluid walls. Various methods are used to reshape cell media on Petri dishes into almost any imaginable pattern. The simplicity of the technique eliminates the need for expensive machinery and equipment. The system is shown to be biocompatible and to have potential for high-throughput cell-based analysis. This technology allows the user to fabricate a wide variety of microfluidic devices truly on demand (within minutes).

Beyond simple proof-of-concept applications, this technology produces several important results: miniaturized CRISPR-Cas9 assays in volumes smaller than 1 µl, a fluorescent method for measuring small volumes, a method to reconfigure cellular environments around living cells, a way to accelerate single-cell cloning, beating the Poisson distribution in single-cell cloning, designing and creating a perfusion device which can continuously feed cells over days, and a method for dislodging attached cells and creating wounds in vitro. In its entirety, this thesis puts forward a set of methods to model and reshape cellular environments using apparatus accessible to common biology laboratories: a 3-axis traverse, syringe pumps, petri dishes, cell media and FC40.

Authors: Castrejón-Pita, A

• DOI: 10.5287/ora-ko1qebkjd
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: microfluidics; fluid walls
• Subjects: Engineering; Bioengineering