In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices

TL;DR

This paper introduces a multicore fibre-based pH mapping system for microfluidic devices, enabling in-situ, high-resolution spatial pH measurements through obstacles, surpassing single-core fibre limitations.

Contribution

It presents a novel multicore fibre sensor system for in-situ pH mapping in microfluidics, offering improved spatial resolution and obstacle penetration capabilities.

Findings

Successful pH measurements through obstacles like glass and rock beads.

Demonstrated spatial resolution of tens of micrometers.

Independent measurement channels using fibre cores.

Abstract

Microfluidic systems with integrated sensors are ideal platforms to study and emulate processes such as complex multiphase flow and reactive transport in porous media, numerical modeling of bulk systems in medicine, and in engineering. Existing commercial optical fibre sensing systems used in integrated microfluidic devices are based on single-core fibres, limiting the spatial resolution in parameter measurements in such application scenarios. Here, we propose a multicore fibre-based pH system for in-situ pH mapping with tens of micrometer spatial resolution in microfluidic devices. The demonstration uses custom laser-manufactured glass microfluidic devices (called further micromodels) consisting of two round ports. The micromodels comprise two lintels for the injection of various pH buffers and an outlet. The two-port system facilitates the injection of various pH solutions using independent pressure pumps. The multicore fibre imaging system provides spatial information about the pH environment from the intensity distribution of fluorescence emission from the sensor attached to the fibre end facet, making use of the cores in the fibre as independent measurement channels. As a proof-of-concept, we performed pH measurements in micromodels through obstacles (glass and rock beads), showing that the particle features can be clearly distinguishable from the intensity distribution from the fibre sensor.