The objective of this research is to develop a sensor for the detection of multiple biomarkers with specific application to early detection and monitoring of ovarian cancer. The approach is based on a surface acoustic wave (SAW) transducer that integrates two critical functions, namely, removal of interfering proteins, and sensing of multiple biomarkers, on a single device.
Technical Merit This project is the first to propose and demonstrate removal of non-specifically bound (NSB) proteins from sensor surfaces using SAWs. NSB is a confounding factor for sensor response utilizing any sensing principle, optical, electrochemical or mass change. The proposed sensor is the first to integrate this removal function with the sensing function of any device. This is the first attempt at differential removal of bound proteins, one at a time, to achieve detection and quantification of multiple moieties on a single device surface. Many diseases, such as ovarian cancer, are characterized by elevated levels of select proteins in bodily fluids. Hence, this sensor will have wide applicability in medical diagnostics.
Broader Impact This work will allow for more wide-spread and easy testing than current practice and is also applicable to detection of multiple moieties for environmental and chemical detection applications. The proposed pilot testing of an interdisciplinary senior design project can lead to a sustainable model for engineering education. Proposed hands-on sensor units and associated experiments will lead to awareness of basic sensor principles and concepts among the participating school children. The proposed minority mentoring program can lead to recruitment into science and engineering programs.
A surface acoustic wave (SAW) biosensor for detection of ovarian cancer and other biomarkers in immunosensing format has been developed in this research. This sensor utilizes shear horizontal SAWs to qualtify biomarkers, and Rayleigh waves propagating in a different direction on the surface of a piezoelectric solid to remove non-specifically bound proteins, and to improve mixing, resulting in a more sensitive and precise quantification of the biomarkers, than when using shear horizontal waves alone. Microcavities in the delay-path of the SAW sensor were investigated for their ability to reduce power consumption, to enhance removal efficiency of the non-specifically bound proteins, and to improve sensitivity. Several piezoelectric substrates (ST quartz, lithium niobate, lithium tantalate and langasite) were considered for the design of these devices. Several wave guide, and filling materials for the microcavities were also considerd to study their effect on sensing and removal functions. Fluid-solid-interaction finite element models were developed and utilized for the design of these devices. This research has broad utility in the detection of a variety of biomarkers, leading to prognostic and diagnostic sensor applications. The removal function is applicable to other sensing methods, such as optical and electrochemical, and is expected to transform the area of biosensing in terms of improved reliability and sensitivty of biomarker detection. Developoment of reliable sensors will transform the medical diagnostic field and lead to much improved healthcare.
