Single virus particle mass detection using microresonators with nanoscale thickness

Abstract

In this letter, we present the microfabrication and application of arrays of silicon cantilever beams as microresonator sensors with nanoscale thickness to detect the mass of individual virus particles. The dimensions of the fabricated cantilever beams were in the range of 4–5 μm in length, 1–2 μm in width and 20–30 nm in thickness. The virus particles we used in the study were vaccinia virus, which is a member of the Poxviridae family and forms the basis of the smallpox vaccine. The frequency spectra of the cantilever beams, due to thermal and ambient noise, were measured using a laser Doppler vibrometer under ambient conditions. The change in resonant frequency as a function of the virus particle mass binding on the cantilever beam surface forms the basis of the detection scheme. We have demonstrated the detection of a single vaccinia virus particle with an average mass of 9.5 fg. These devices can be very useful as components of biosensors for the detection of airborne virus particles.

Cantilever biosensors for detection of viruses and bacteria

“…Антитела к гепати там А и С были иммобилизованы на разных кан тилеверах, предел обнаружения составил 0,1 нг/мл (1,6 пМ). Гупта в работе [21] показал, что чувстви тельности кантилевера по измерению массы доста точно, чтобы взвесить отдельный вирус коровьей оспы, однако он не использовал специфичного сен сорного слоя.…”

“…Antibodies to hepatitis A and C were immobilized on differ ent cantilevers, the detection limit was 0.1 ng/ml (1.6 pmole). Gupta in [21] showed that the sensitivity of the cantilever to measure the mass is enough to weigh single vaccinia virus, but he did not use a specific sensor layer.…”

Mass sensor utilising the mode-localisation effect in an electrostatically-coupled MEMS resonator pair fabricated using an SOI process

“…The adsorption of gold atoms onto a nanoscale silicon carbide (SiC) clamped-clamped beam has been detected successfully through resonant frequency-shift [2]. Other studies have demonstrated the resonant detection of single-stranded DNA (ssDNA) probes [3] and Vaccinia virus particles [4] immobilised on microstructures. The detection of various biological elements is 10 a widely researched area of resonant mass sensing with functionalised surfaces promoting the attachment of the target analytes.…”

Integrated MEMS/NEMS Resonant Cantilevers for Ultrasensitive Biological Detection

“…With precise optical detection of atomic force microscopy (AFM), a single cell or virus has been sensed in air environment [8,9]. In ultrahigh vacuum, the resonant cantilevers even showed the mass resolution as high as attogram level [10].…”

“…Differently, the dynamic detecting method employs the cantilever as a resonator. Induced by specific mass adsorbate, a shift in the resonant frequency is read out as the sensing signal [7][8][9][10][11].…”