Label-free detection of human prostate-specific antigen (hPSA) using film bulk acoustic resonators (FBARs)

Abstract

Label-free detection of cancer biomarkers using low cost biosensors has promising applications in clinical diagnostics. In this work, ZnO-based thin film bulk acoustic wave resonators (FBARs) with resonant frequency of ~1.5 GHz and mass sensitivity of 0.015 mg/m 2 (1.5 ng/cm 2) have been fabricated for their deployment as biosensors. Mouse monoclonal antibody, anti-human prostatespecific antigen (Anti-hPSA) has been used to bind human prostate-specific antigen (hPSA), a model cancer biomarker used in this study. Ellipsometry was used to characterize and optimise the antibody adsorption and biomarker antigen binding on gold surface. It was found that the best amount of antibody at the gold surface for effective antigen binding is around 1 mg/m 2 , above or below which resulted in the reduced antigen binding due to either the limited binding sites (below 1 mg/m 2) or increased steric effect (above 1 mg/m 2). The FBAR data were in good agreement with the data obtained from ellipsometry. Antigen binding experiments using FBAR sensors demonstrated that FBARs have the capability to precisely detect antigen binding, thereby making FBARs an attractive low cost alternative to existing cancer diagnostic sensors.

A Novel Bulk Acoustic Wave Resonator for Filters and Sensors Applications

“…AlN based BAW resonators have two basic architectures: Thin Film Bulk Acoustic Wave Resonator (FBAR), which is suspended above an air cavity, and Solidly Mounted Resonator (SMR), which utilizes a series of high and low impedance reflectors to isolate the resonator from the substrate. Thanks to their miniature sizes, high quality factors (Q) in air, and compatibilities with integrated circuit processing, BAW resonators have been used in a widespread applications, such as filters and duplexers in communication electronics [1,2], oscillators for frequency control, gravimetric sensors for physical [3], chemical [4] and biological [5,6] sensing, and general physics applications [7].…”

Film bulk acoustic resonators (FBARs) as biosensors: A review

“…The fr of an FBAR device is correlated with the acoustic velocity, vs, by fr = vs/2h, here h is the thickness of the piezoelectric film, thus it can be adjusted by the thickness of the piezoelectric thin films once the piezoelectric material to be used is determined (Garcia-Gancedo et al 2011a). The thicknesses of the piezoelectric thin films used in FBARs are commonly in sub-micrometre to a few micrometres, resulting in fr ranging from a few GHz to a few hundreds of MHz (Gao et al 2016;Katardjiev and Yantchev 2012;Zhao et al 2014).…”

“…Therefore, both the surface density and the molecular orientation of the immobilized antibodies determine the final antigen capture efficiency and the sensor performance. Figure 4 Real-time and label-free detection of PSA using FBARs have been investigated by different research groups in the last decade (Lin et al 2011;Zhao et al 2014;Zhao et al 2011;Zhao et al 2012b). The first prototype FBAR sensor which was able to detect PSA concentration in hundreds of ng/ml range was reported by Lin et al (Lin et al 2011) who immobilized the electrode surfaces with orientated antibodies (i.e.…”

Self-Sustaining Square-Extensional Mode Resonator Oscillator for Mass Sensing in Liquid

“…The sensing environment is a critical consideration, particularly when the sensing must be carried out in a fluidic environment. Microelectromechanical Systems (MEMS) resonators designed to interact with fluids are of interest for sensing the physical properties of liquids [1] and biosensing [2] as they allow for high throughput, real-time monitoring, and require low sample volumes. Ideally, such a resonator should deliver a workable signal-to-noise ratio.…”