Enhanced accumulation of colloidal particles in microgrooved channels via diffusiophoresis and steady-state electrolyte flows Guido Bolognesi 2,5 , Naval Singh 1 , Goran Vladisavljević 2 , Francois Nadal 3 , Cecile Cottin-Bizonne 4 , Christophe Pirat 4 1 University of Manchester, UK, 2 Loughborough University, UK, 3 Commissariat à l'Energie Atomique (CEA), France, 4 Université Claude Bernard Lyon 1, France, 5 University College London, UK The controlled transport of sub-micron colloidal particles within a confined environment, such as a porous medium or a dead-end channel, is a key feature in several technological applications (e.g., drug delivery, diagnostics) as well as in living systems (e.g., mass transport in tissues and capillaries). The ability to manipulate particles by diffusiophoresis – a phoretic phenomenon leading to particle motion along a solute concentration gradient without the use of an external field – has gained an increasing attention 1 . Recently, we demonstrated how solute gradients in steady-state continuous flows past a microgrooved surface can be exploited to induce the controlled and reversible trapping of sub-micron particles within the dead-end grooves. The trapping mechanism is governed by a combination of hydrodynamic effects and diffusiophoresis particle migration 2-3 . In this study, we investigate how the particle trapping is affected by the groove geometry, channel surface chemistry and solute gradient intensity, thereby determining the conditions for enhancing the particle trapping performance 4 . We also extended the manipulation strategy to a wider range of colloidal particles. The proposed approach for particle transport in lab-on-a-chip devices has potential applications in point-of-care, drug delivery and biosensing industry. References 1. S.Shim, Diffusiophoresis, diffusioosmosis, and microfluidics: surface-flow-driven phenomena in the presence of flow. Chemical Reviews , 2022 ,122, 6986-7009, 2. N.Singh, N., G.T. Vladisavljević, F. Nadal, C. Cottin-Bizonne, C. Pirat, and G. Bolognesi, Reversible trapping of colloids in microgrooved channels via diffusiophoresis under steady-state solute gradients. Physical Review Letters , 2020 ,125,248002. 3. N.Singh, A. Chakra, G.T. Vladisavljević, C. Cottin-Bizonne, C. Pirat, and G. Bolognesi, Composite Norland Optical Adhesive (NOA)/silicon flow focusing devices for colloidal particle manipulation and synthesis. Colloids and Surfaces A: Physicochemical and Engineering Aspects , 2022 ,652, 129808. 4. N.Singh, N., G.T. Vladisavljević, F. Nadal, C. Cottin-Bizonne, C. Pirat, and G. Bolognesi,Enhanced accumulation of colloidal particles in microgrooved channels via diffusiophoresis and steady-state electrolyte flows. Langmuir , 2022 ,38,14053-14062.
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