Research interests

1. Micro- and Nanobubbles for the treatment of : Cancer, bacterial infection, as we ll as for oxygen delivery.

In particular we have developed a microfluidics platfform for the delivery of therapeutic agents. We are also developing on chip systems for studying therapeutic delivery to organoids for pancreatic, colorectal and bladder models.

2. Single Cell Phenotyping.  Here we are using using molecular deformation, Raman spectroscopy and surface acoustic wave dielectrophoresis for the manipulation and characterisation of cells at the single cell level - in high throughput.

3. Nanotubes and Nanorods. We are developing novel  nanomaterials for applications in photothermal treatment and imaging of cancer.

4. Lipid Membranes. We use model lipid membranes for developing our understading the membrane proteins, in particular we are interested in the fcGR.

5. Lipid Coated liquid crystal biosensors. We are using lipid coated LC droplets as self-amplification systems for the detection of bacterial infection

ABSTRACT

Author: Stephen D. Evans1, Fern J. Armistead1, Julia Gala De Pablo1, Sally A. Peyman1, Hermes Gadelha2

1.Molecular and Nanoscale Physics Group, Department of Physics and Astronomy, University of Leeds, Leeds, United Kingdom.

2. Department of Mathematics, University of York, York, United Kingdom

Abstract: The deformability of a cell is the direct result of a complex interplay between the different constituent elements at the subcellular level, coupling a wide range of mechanical responses at different length scales. Changes to the structure of these components can also alter cell phenotype, which points to the critical importance of cell mechanoresponse for diagnostic applications.

The response to mechanical stress depends strongly on the forces experienced by the cell. Here, we use cell deformability in both shear-dominant and inertia-dominant microfluidic flow regimes to probe different aspects of the cell structure. In the inertial regime, we follow cellular response from (visco-)elastic through plastic deformation to cell structural failure and show a significant drop in cell viability for shear stresses >11.8 kN/m2. Comparatively, a shear-dominant regime requires lower applied stresses to achieve higher cell strains. From this regime, deformation traces as a function of time contain a rich source of information including maximal strain, elastic modulus, and cell relaxation times and thus provide a number of markers for distinguish- ing cell types and potential disease progression.

These results emphasize the benefit of multiple parameter determination for improving detection and will ultimately lead to improved accuracy for diagnosis. We present results for leukemia cells (HL60) as a model circulatory cell as well as for colorectal cancer cell lines, from different stages of disease progression, to demonstrate that the approach can distinguish between these and has the potential for improving our understanding the relationship between mechanical response and molecular

References: 1    Armistead, F. J., Gala De Pablo, J., Gadelha, H., Peyman, S. A. & Evans, S. D. Cells Under Stress: An Inertial-Shear Microfluidic Determination of Cell Behavior. Biophys J, doi:10.1016/j.bpj.2019.01.034 (2019).

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