Adoptive cell therapies have achieved successful clinical outcomes in the treatment of numerous malignant tumours. This approach typically involves cytotoxic T cells that can be engineered or selected ex vivo, expanded, and then re-injected to specifically target tumour cells with enhanced potency. Currently deployed strategies for selecting optimal T cell receptor (TCR) T cell clones for cancer treatments include surface plasmon resonance (SPR) and tetramer based technologies using fluorescent-activated cell sorting (FACS). These conventional methods have generated useful information on TCR affinities and binding kinetics. However, several limitations persist including false negative readouts of bulk populations, expensive peptide products, time-consuming processes and fails to assess all intercellular interactions that contribute to immunological synapse formation. Thus, affinity readouts have provided poor predictions of T cell functionality. On the other hand, analysing cellular avidity (i.e. overall intercellular binding strength) generates a more complete and physiologically relevant parameter that reflects the bona fide T cell – tumour cell interactions. To overcome existing limitations, new biophysical technologies such as microfluidics are required to rapidly and accurately examine cell avidity under high throughput. This approach will improve current T cell selection methods used for cellular immunotherapies and thus, enable clinicians to treat a wider range of cancers with greater efficacy.

In this work, we developed a microfluidic device capable of rapidly identifying, sorting and collecting T cell receptor (TCR) T cells with high cell avidities and highly cytotoxic functionalities to adherent tumour monolayers using shear-induced flow. These results demonstrated how microfluidic technology can improve the predictability, cost, physiology and speed of T cell selection methods that takes into account the strength of all cell-cell interactions. Ultimately, this work presents a proof-of-concept study on a new technology that has the potential in the future to identify rare T cell clones with optimal cellular avidities out of pool of heterogeneous patient derived T cell samples, providing critical steps towards precision medicine.