Session: 01-02: Micro/Nanofluidics and Lab-On-A-Chip

Paper Number: 132855

132855 - Detection of Sars-Cov-2 Using a Microwave Sensor Integrated in a Microfluidic Platform 

Abstract: 

The global COVID-19 pandemic continues to have an unprecedented impact on both the economy and society. Although the traditional reverse transcription polymerase chain reaction technique is the gold standard for virus detection due to its high accuracy and specificity, its limitations hinder the capability for rapid testing such as being time-consuming, expensive, and requiring complex equipment. The development of point-of-care testing devices is recognized as an effective strategy for real-time detection in diverse environments. Due to variations in dielectric constants and conductivity, different materials exhibit distinct electrical characteristics under an applied electric field. Microwave sensors can distinguish between materials by detecting their dielectric properties, and have the advantages of high sensitivity, easy manufacturing, low cost, and portability, making them widely used in the field of bio-sensing. In this work, we integrated microwave sensor and microfluidic technologies to present a novel proof-of-concept of a microfluidic microwave sensing method for point-of-care (POC) diagnosis of the SARS-CoV-2 virus. This method employs antibodies immobilized to the microwave sensor to selectively capture and concentrate the SARS-CoV-2 antigens or viruses present in the buffer solution flowing through the microchannel in the sensor area. After immobilizing antibodies with specificity on the sensor, the microwave sensor exhibited a frequency shift of approximately 13 MHz within 90 minutes, whereas the uncoated sensor showed almost no frequency movement, which indicates the successful immobilization of the antibody coating on the microwave sensor. The use of microchannel offers precise control of the sample volume and the continuous flow nature also offers the potential to monitor the dynamic capturing process, which exhibits characteristics such as small size, automation, and integration. With the continuous injection of virus samples, the frequency shifts increase over time, which indicates that capture of SARS-CoV-2 antigen or virus occurred. The reason is that the capturing of the SARS-CoV-2 antigen or virus results in a change in the permittivity of the medium near the sensor region reflected by the resonance frequency shift which is used for detection. The results show the sample with 100000 copies per ml virus results in a frequency shift of 12MHz and 4000 copies per ml a frequency shift of 3.5 MHz at the time of 90 min. The microwave-microfluidic device shows a good sensitivity of 0.1 ng ml^-1 for the SARS-CoV-2 antigen and 4000 copies per ml for the SARS-CoV-2 virus. The resonance frequency shift presents a linear relationship with the logarithm of antigen or virus concentration, respectively. In addition, we performed experiments in a buffer containing 10% saliva and found that saliva had little effect on frequency changes, indicating that this method has the potential to directly detect real samples. This method can directly detect samples containing SARS-CoV-2 antigen or virus, and the entire process is simple and accurate without any taxing work, which is indeed appropriate for use at mobile testing stations or household use. Furthermore, this detection method is able to distinguish SARS-Cov-2 and two human coronaviruses, which presents a new pathway towards POC diagnosis of COVID-19 at the community level. it presents the potential to detect other viruses by functionalizing the microwave sensor with respective antibodies.

Presenting Author: Pei Zhao Shandong University

Presenting Author Biography: Dr. Pei Zhao is currently a full professor at the School of Energy and Power Engineering, Shandong University, China. Before joining Shandong University, She was a senior research associate and later a research assistant professor working at the Department of Mechanical and Mechatronics Engineering, University of Waterloo, Canada for almost 7 years. She holds a PhD degree in Inorganic Chemistry from the Chinese Academy of Sciences. Her current research interests are about interfacing advanced functional materials with microfluidics for environmental and medical applications.

Authors:

Pei Zhao Shandong University
Ning Qin Shandong University