Integrated active mixing and biosensing using surface acoustic waves (SAW) and surface plasmon resonance (SPR) on a common substrate

Abstract

This article presents a device incorporating surface plasmon resonance (SPR) sensing and surface acoustic wave (SAW) actuation integrated onto a common LiNbO(3) piezoelectric substrate. The device uses Rayleigh-type SAW to provide active microfluidic mixing in the fluid above the SPR sensor. Validation experiments show that SAW-induced microfluidic mixing results in accelerated binding kinetics of an avidin-biotin assay. Results also show that, though SAW action causes a parasitic SPR response due to heat injection into the fluid, a relatively brief relaxation time following the SAW pulses allows the effect to dissipate, without affecting the overall assay response. Since both SPR sensors and SAW transducers can be fabricated simultaneously using low-cost microfabrication methods on a single substrate, the proposed design is well-suited to lab-on-chip applications.

Micromachined Thermal Flow Sensors—A Review

“…The intended purpose is to use the SAW action to induce fluid flow and utilize SPR for sensing a target analyte. However, it was reported that the SAW action creates localized heating, which may be observed through SPR [95]. …”

“…This coupling is sensitive to changes in thickness, chemical species, and temperature, which manifests as a variation in reflectivity [95,96].…”

Accelerated surface plasmon resonance biosensing by surface acoustic waves microstreaming

“…As expected, the results show SPR reflectivity curves shifting to the right (larger angles of minimum reflectivity) with increasing refractive index. This experiment demonstrates that SPR can be performed on a LiNbO3 substrate with results very similar to that obtained with glass substrates, a prerequisite for combining SAW and SPR on a common piezoelectric substrate [12].…”

Plasmonic gold nanodiscs using piezoelectric substrate birefringence for liquid sensing

“…12,13 The planar configuration of SAW devices is also suitable for LOAC formats. 9 In this paper we investigate the potential for co-integration of acoustic and SPR technologies on a single device, and in particular to study the optical properties of SPR nanostructures on piezo-active materials. In order to do this we have selected the piezo-active material LiNbO3, as it has high optical transmission (we obtain over 80% in visible range), large electromechanical coupling coefficients, as well as being optically birefringent unlike the glasses typically used to make SPR sensors.…”

“…7 SAW devices can be used to induce a liquid flow by acoustic streaming, 8 and this phenomenon has been used in conjunction with a continuous metal film to accelerate and improve analyte capture for SPR sensing. 9,10 Such SPR sensors can be made by coating one surface of a prism with metal and measuring the change in the intensity of totally internally reflected light at different angles. 11 Studies have also been made with patterned metallic planar films in which surface modifications give rise to changes in the observed resonance characteristics.…”