A Siso, Multi-analyte Sensor Based on a Coupled Microresonator Array

This work details a preliminary analytical and experimental investigation of a new class of resonant, single input single output (SISO) microsensors, which are capable of detecting multiple analytes. The key feature of these sensors is that they exploit vibration localization in a set of N microbeams, coupled indirectly through a common shuttle mass, to allow for the detection of N distinct resonance shifts (induced by the presence of up to N distinct analytes) using solely the shuttle mass’ response. The work includes a brief overview of the proposed sensor design, the formulation and subsequent analysis of a representative lumpedmass model of the sensor, and details of a recently-completed simulated mass detection experiment, which verified the feasibility of the proposed sensor design. Where appropriate, practical design issues, essential to sensor development, are described. INTRODUCTION Chemical, biological, and mass sensors based on resonant microsystems have been proposed for use in a wide variety of applications ranging from environmental monitoring to medical ∗Address all correspondence to this author. diagnostics [1–14]. The principal interest in such devices stems not only from their broad applicability, but also the reduction in size and power and the potential for improved sensitivity they offer. Typically, resonant microsensors exploit induced resonance shifts for sensing. As these shifts arise from mass or stiffness changes in the oscillator, caused by adsorption, desorption, or local stress stiffening at the oscillator’s surface, they can be used to identify the presence of a target analyte [15–17]. Unfortunately, due to the practical limitations of surface science and the fact that the oscillators typically feature a single dominant degree-of-freedom (SDOF), only a lone analyte or group of analytes can generally be detected through this approach. Arrays of isolated oscillators, individually functionalized to detect a specific analyte, can be used to broaden detection capabilities (see, for example, [16]), but the inherent complexity of such arrays (arising from increased hardware and signal processing requirements) limits their utility. This work presents a novel sensor architecture that realizes the detection capabilities of a resonant sensor array in the context of a single input single output (SISO) system. This is accomplished by mechanically coupling an array of frequencymistuned microbeam resonators, each functionalized to a given 1 Copyright c © 2006 by ASME