Controlling adhesive dynamics of cancer cells using external electric field
Adhesive dynamics of cells plays a critical role in determining different biophysical processes orchestrating health and disease in the living systems. While the rolling of cells on functionalized substrates having similitude with biophysical pathways appears to be extensively discussed in the literature, the effect of an external stimulus in the form of electric field on the same remains underemphasized. Here, we bring out the interplay of fluid shear and electric field on the rolling dynamics of adhesive cells in biofunctionalized micro-confinements. Our experimental results portray that an electric field, even restricted to low strengths within the physiologically relevant regimes, can significantly influence the cell adhesion dynamics. We quantify the electric field-mediated adhesive dynamics of the cells in terms of two key parameters, namely, the voltage-altered rolling velocity and the frequency of adhesion. The effect of the directionality of the electric field with respect to the flow direction is also analysed by studying cellular migration with electrical effects acting both along and against the flow. Our experiment, on one hand, demonstrates the importance of collagen functionalization on the adhesive dynamics of cells through micro channels, while on the other hand, it reveals how the presence of an axial electric field can lead to significant alteration in the kinetic rate of bond breakage, thereby modifying the degree of cell-substrate adhesion and quantified in terms of the adhesion frequency of the cells. Proceeding further forward, we offer a simple theoretical explanation towards deriving the kinetics of cellular bonding in the presence of an electric field, which corroborates favourably with our experimental outcome. These findings are likely to offer fundamental insights on the possibilities of local control of cellular adhesion via electric field mediated interactions, bearing critical implications in a wide variety of medical conditions ranging from wound healing to cancer metastasis.
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Laha, S., Dhar, D., Adak, M., Bandopadhyay, A., Das, S., Chatterjee, J., & Chakraborty, S. (2024). Electric field-mediated adhesive dynamics of cells inside bio-functionalised microchannels offers important cues for active control of cell-substrate adhesion. Soft Matter. (Accepted)
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An Indian patent has been filed based on the above study, Application number : 202231051636, Sampad Laha and Suman Chakraborty (2022)
Dynamics of red blood cells through porous media
Understanding the complex spreading dynamics of physiological fluids on paper matrix holds paramount importance in dictating the functionalities of a wide variety of diagnostic kits that are now-a-days being deployed for rapid point-of-care diagnostics with different physiological fluids. In contrast to the intuitive paradigm that dynamics of whole blood on paper is likely to be strongly dependent on the patient-specific variations in the compositions of its micro-constituents in general, more specifically on the packed volume fraction of red blood cells ( also known as the blood hematocrit level), here we show that the diffusive dynamics of a finite volume of human whole blood on a paper strip , follows a universal characteristics independent of the hematocrit level in the normal healthy regime. Our results also confirm the distinctive difference between the diffusive characteristics of whole blood and plasma, thereby unveiling the key influence of the in-situ formation of cellular aggregates and the consequent obstructions in the randomly distributed hierarchically structured porous passages of paper. This aspect, in conjunction with the unique implication of a finite volume of blood, is consistent with typical on-field point-of-care diagnostic practices. Comprehensive experimental studies with a wide range of patient-derived blood samples, well complemented with a semi-analytical mathematical modelling, eventually lead to a quantitative feature of spreading behavior that applies generically to all paper-based detection systems for blood-based pathological tests.
Laha, S., Kar, S., & Chakraborty, S. (2023). Cellular aggregation dictates universal spreading behaviour of a whole-blood drop on a paper strip. Journal of Colloid and Interface Science, 640, 309-319.