Ultimate and practical limits of fluid-based mass detection with suspended microchannel resonators

Abstract

Suspended microchannel resonators ͑SMRs͒ are an innovative approach to fluid-based microelectromechanical mass sensing that circumvents complete immersion of the sensor. By embedding the fluidics within the device itself, vacuum-based operation of the resonator becomes possible. This enables frequency shift-based mass detection with high quality factors, and hence sensitivity comparable to vacuum-based micromechanical resonators. Here we present a detailed analysis of the sensitivity of these devices, including consideration of fundamental and practical noise limits, and the important role of binding kinetics in sensing. We demonstrate that these devices show significant promise for protein detection. For larger, biologically-important targets such as rare whole virions, the required analysis time to flow sufficient sample through the sensor can become prohibitively long unless large parallel arrays of sensors or preconcentrators are employed.

Other Surface-Acoustic-Wave Based Instruments

“…Examples are the cantilever [43], the paddlever [44], the trampoline resonator [45], the doubly clamped beam [46], the FBAR [47,48], the contour-mode resonator [49], the capacitive micromachined ultrasonic transducer (CMUT) [50], and the suspended microchannel resonator (SMR) [51]. For a review, see Ref.…”

A probe with ultrathin film deflection sensor for scanning probe microscopy and material characterization

“…Piezoresistive deflection-sensing elements are integrated onto micromachined cantilevers to increase sensitivity, and reduce complexity and cost. These sensing elements are made by selectively doping silicon [9][10][11], by depositing and patterning metal or metal oxide films, such as gold [12][13][14], indium tin oxide [15,16], and nichrome [17], or by depositing and patterning other materials such as amorphous carbon [18].…”

Suspended nanochannel resonators at attogram precision

“…We then estimated the diameter of each nanoparticle (Fig. 4B), assuming each particle is spherical and equally dense (the density of gold is 19.3 g/cm 3 ). The estimated mean size is 9.83 nm with a coefficient of variance of 6.9%, which agrees well with the manufacturer specification of 9.9 nm.…”

“…Previously, the performance of nanomechanical resonators in vacuum has been studied extensively. However, SNRs received only theoretical approaches so far [3] to study their limits of detection. Previously as a proof of concept for nanoparticle detection, SNRs achieved a limit of detection higher than 100 attograms at 1 kHz bandwidth [2], far above the limit imposed by the thermal noise at room temperature.…”