名师讲座
报告题目：Steering colloids with salt gradients: from material characterisation to diagnostics
报告时间：2026-11-19 10:00
报告人： Associate Professor Guido Bolognesi
University College London
报告地点：翔安校区嘉庚实验室3号楼2楼报告厅
转播地点：思明校区国重234教室；漳州校区生化主楼307教室
报告摘要：
Salt concentration gradients, ubiquitous in nature and easy to create in laboratory settings, can move colloidal particles and drive liquid flows without any external field. In this talk, I will show how this phenomenon can be exploited in microfluidic devices to manipulate synthetic and biological particles for material characterisation, bioanalysis and diagnostics.
Combining experiments with numerical simulations, I will first discuss how the interplay between diffusiophoresis and diffusioosmosis (the transport of particles and liquids, respectively, induced by salt gradients) enables the reversible trapping of particles in dead-end pores and their focusing in straight channels under continuous flow. I will then present microdevices that use these mechanisms to separate polymer particles continuously by size and surface chemistry, and to measure the zeta potential and the fraction of charged lipids of small unilamellar vesicles. The same strategy also allows protein corona-coated polymer beads to be detected and separated from bare particles. Requiring only simple devices and no external energy sources, this approach offers an accessible platform for both fundamental studies of colloids and new tools for chemical analysis and diagnostics.
Finally, I will show how salt-driven particle manipulation can be implemented in paper-based microfluidics, and present a strategy that enhances the sensitivity of lateral flow assays by manipulating gold nanoparticles during the assay, opening a route to more sensitive, low-cost, point-of-care diagnostics for resource-limited settings.
References
[1] N. Singh et al., Physical Review Letters, 125, 248002 (2020).
[2] A. Chakra et al., ACS Nano, 17, 14644-14657 (2023).
[3] A. Chakra et al., Journal of Colloid and Interface Science, 693, 137577 (2025).
[4] C. Puijk et al., Flow, 6, E26 (2026)
报告人简介：
Guido Bolognesi is Associate Professor in Physical Chemistry in the Department of Chemistry at University College London, which he joined in 2023. He received a joint PhD in Theoretical and Applied Mechanics from the University of Rome “La Sapienza” and the University Claude Bernard Lyon 1. From 2012 to 2016, he was a postdoctoral research associate in the Department of Chemistry at Imperial College London, where he developed microfluidic methods for the synthesis, characterisation and optical manipulation of functional emulsion droplets. From 2016 to 2022, he was Lecturer and then Senior Lecturer in Bioengineering in the Department of Chemical Engineering at Loughborough University. His research investigates transport processes and interfacial phenomena in microfluidic and paper-based systems, including particle manipulation by salt concentration gradients, and harnesses them to develop new technologies for biosensing, synthetic biology, therapeutics and drug delivery. His work is funded by UK Research and Innovation, the Royal Society and the European Innovation Council. He is Chair of the Institute of Physics Liquids and Complex Fluids Special Interest Group and a member of the Early Career Advisory Board of Langmuir.
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