Acoustic Biosensors and Microfluidic Devices in the Decennium: Principles and Applications

Abstract

Lab-on-a-chip (LOC) technology has gained primary attention in the past decade, where label-free biosensors and microfluidic actuation platforms are integrated to realize such LOC devices. Among the multitude of technologies that enables the successful integration of these two features, the piezoelectric acoustic wave method is best suited for handling biological samples due to biocompatibility, label-free and non-invasive properties. In this review paper, we present a study on the use of acoustic waves generated by piezoelectric materials in the area of label-free biosensors and microfluidic actuation towards the realization of LOC and POC devices. The categorization of acoustic wave technology into the bulk acoustic wave and surface acoustic wave has been considered with the inclusion of biological sample sensing and manipulation applications. This paper presents an approach with a comprehensive study on the fundamental operating principles of acoustic waves in biosensing and microfluidic actuation, acoustic wave modes suitable for sensing and actuation, piezoelectric materials used for acoustic wave generation, fabrication methods, and challenges in the use of acoustic wave modes in biosensing. Recent developments in the past decade, in various sensing potentialities of acoustic waves in a myriad of applications, including sensing of proteins, disease biomarkers, DNA, pathogenic microorganisms, acoustofluidic manipulation, and the sorting of biological samples such as cells, have been given primary focus. An insight into the future perspectives of real-time, label-free, and portable LOC devices utilizing acoustic waves is also presented. The developments in the field of thin-film piezoelectric materials, with the possibility of integrating sensing and actuation on a single platform utilizing the reversible property of smart piezoelectric materials, provide a step forward in the realization of monolithic integrated LOC and POC devices. Finally, the present paper highlights the key benefits and challenges in terms of commercialization, in the field of acoustic wave-based biosensors and actuation platforms.

Biosensors for Food Mycotoxin Determination: A Comparative and Critical Review

“…-Electrochemical-based on the variation of electrochemical properties [46]; -Optical-based on the variation of optical properties [47]; -Thermal biosensors-based on thermal energy variation [48]; -Mass sensitive biosensors-based on mass variation [49]; -Acoustic biosensors-the target analyte is detected through the induced variations in the frequency, velocity, or amplitude of the acoustic waves generated by piezoelectric materials [50].…”

“…The functioning of acoustic wave sensors relies on the monitoring of the variations occurring in the physical characteristics of an acoustic wave imparted by the analyte's presence [50]. Piezoelectric materials are constituted of crystals devoid of a centre of inversion symmetry and presenting an intensified coupling between mechanical strain and electrical polarization.…”

Four-Channel Ultrasonic Sensor for Bulk Liquid and Biochemical Surface Interrogation

“…A common way of classifying acoustic biosensors is bulk acoustic wave (BAW) and surface acoustic wave (SAW) devices. While BAW devices, which utilize the propagation of the acoustic waves through the bulk of the liquid sample and, therefore, are simpler to implement, SAW devices are particularly attractive for biosensing applications since they allow the immobilization of biomolecules of interest onto the bioreceptor sensing layer and quantify their concentration via specific changes in a selected parameter of acoustical wave [12]. Various SAW-based biosensor concepts have already been demonstrated [13].…”

Application of Shear Horizontal Surface Acoustic Wave (SH-SAW) Immunosensor in Point-of-Care Diagnosis

“…These biosensors have some advantages, including being label-free, small in size, reasonable in price, and capable of producing quantitative results using an electrical circuit. Many studies have been published; these have addressed thickness shear mode (TSM) [ 1 , 2 , 3 ], acoustic plate mode (APM) [ 4 ], surface acoustic wave (SAW) [ 5 , 6 , 7 ], bulk acoustic wave (BAW) [ 8 ], and shear horizontal surface acoustic wave (SH-SAW) [ 5 , 9 , 10 , 11 , 12 ]. There are many varieties of different acoustic modes, different frequencies, and different substrate materials.…”