Microfluidic Devices for Microplastics Separation and Identification

Considering its ubiquitous use, plastic pollution has been a worldwide concern for a long time. Recently, microplastics have been found both in water and animal samples (including humans), raising the necessity for novel analytical methods dedicated to the detection of these particles. This thesis explored the application of microfluidic devices in the separation and identification of microplastics. Firstly, the field of low-cost microfluidic devices for environmental applications was reviewed, obtaining an exhaustive perspective. The second chapter explores the development of a device used for microplastics identification using a staining method. The device was made from PDMS casting using a 3D printed mould. It was possible to continuously stain microplastic particles diluted in water samples. The staining quality depended on the device flow rate and operational temperature. The third chapter demonstrates the separation of microplastics from blood samples using acoustic waves. The device was fabricated using a combination of photolithography and lift-off techniques. The interaction between acoustic waves and submerged particles was modelled considering different microplastic types and sizes. The separation was demonstrated, and the effects of power and flow rate were analyzed.