Microfluidic Microwave Sensor for Detecting Saline in Biological Range

• Published in: Sensors (Basel, Switzerland) Vol. 19; no. 4; p. 819
• Main Authors: Kilpijärvi, Joni, Halonen, Niina, Juuti, Jari, Hannu, Jari
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 17-02-2019; MDPI AG
• Subjects: Biosensing Techniques; Humans; IDE; Lab-on-a-chip; Microfluidic Analytical Techniques - methods; Microfluidic sensing; Microwaves; RF sensor; Saline Solution - chemistry; Saline Solution - isolation & purification; Silicones - chemistry; Sodium Chloride - blood; Sodium Chloride - chemistry; Sodium Chloride - isolation & purification; Water - chemistry; RF sensor; IDE; microfluidic sensing; lab-on-a-chip
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s19040819

A device for measuring biological small volume liquid samples in real time is appealing. One way to achieve this is by using a microwave sensor based on reflection measurement. A prototype sensor was manufactured from low cost printed circuit board (PCB) combined with a microfluidic channel made of polymethylsiloxane (PDMS). Such a sensor was simulated, manufactured, and tested including a vacuum powered sample delivery system with robust fluidic ports. The sensor had a broad frequency band from 150 kHz to 6 GHz with three resonance frequencies applied in sensing. As a proof of concept, the sensor was able to detect a NaCl content of 125 to 155 mmol in water, which is the typical concentration in healthy human blood plasma.