Rapid accumulation of colloidal microspheres flowing over microfabricated barriers

TL;DR

This study models plaque-like particle accumulation in microfluidic channels, revealing that surface roughness significantly influences buildup, while electrostatic forces have a minor effect.

Contribution

It introduces a microfluidic simulation of arterial plaque formation, highlighting the dominant role of surface roughness over electrostatic interactions.

Findings

Surface roughness increase causes a dramatic rise in accumulation.

Electrostatic force reduction has only a minor impact on buildup.

Simulated accumulation mimics arterial plaque formation.

Abstract

Accumulation of particles while flowing past constrictions is a ubiquitous phenomenon observed in diverse systems. Some of the common examples are jamming of salt crystals near the orifice of salt shakers, clogging of filter systems, gridlock in traffics etc. For controlled studies, accumulation events are often examined as clogging process in microfluidic channels. Experimental studies thus far have provided with various physical insights, however, they fail to address commonly encountered accumulation events relevant to human health such as dental and arterial plaques. We simulate arterial plaque like accumulation events by flowing colloidal microspheres over micro-structured barriers in microfluidic environment. Our experiments reveal the role of electrostatic, contact and hydrodynamic forces in facilitating plaque-like build up events. A decrease in Debye length (electrostatic repulsion) between interacting surface by two orders leads to only a minor increase in accumulation. In contrast, an increase in the roughness by 3 times results in dramatic rise of accumulation.