# A Novel Microfluidics Droplet-Based Interdigitated Ring-Shaped Electrode Sensor for Lab-on-a-Chip Applications

## TL;DR

This paper introduces a new microfluidics sensor for detecting and analyzing nanoliter droplets, which could advance biomedical and chemical research.

## Contribution

A novel microsensor with interdigitated ring-shaped electrodes and integrated microfluidic channels for droplet analysis is introduced.

## Key findings

- The sensor can analyze droplets with lengths of 1.0–6.0 mm and velocities of 0.66–2.51 mm/s.
- It achieves droplet volumes ranging from 1.07 nL to 113.46 nL with high signal amplitude and real-time detection.
- The platform shows potential for biomedical research, drug discovery, and on-chip biosensor applications.

## Abstract

This paper presents a comprehensive study focusing on the detection and characterization of droplets with volumes in the nanoliter range. Leveraging the precise control of minute liquid volumes, we introduced a novel spectroscopic on-chip microsensor equipped with integrated microfluidic channels for droplet generation, characterization, and sensing simultaneously. The microsensor, designed with interdigitated ring-shaped electrodes (IRSE) and seamlessly integrated with microfluidic channels, offers enhanced capacitance and impedance signal amplitudes, reproducibility, and reliability in droplet analysis. We were able to make analyses of droplet length in the range of 1.0–6.0 mm, velocity of 0.66–2.51 mm/s, and volume of 1.07 nL–113.46 nL. Experimental results demonstrated that the microsensor’s performance is great in terms of droplet size, velocity, and length, with a significant signal amplitude of capacitance and impedance and real-time detection capabilities, thereby highlighting its potential for facilitating microcapsule reactions and enabling on-site real-time detection for chemical and biosensor analyses on-chip. This droplet-based microfluidics platform has great potential to be directly employed to promote advances in biomedical research, pharmaceuticals, drug discovery, food engineering, flow chemistry, and cosmetics.