Detection of bacterial cells and antibodies using surface micromachined thin silicon cantilever resonators

Abstract

This article describes a surface micromachined cantilever beam-based resonator for biological sensing applications. The study used a novel microfabrication technique of merged epitaxial lateral overgrowth (MELO) and chemical mechanical polishing (CMP) to fabricate thin, low stress, single-crystal silicon cantilever beams. The vibration spectra of the cantilever beams, excited by thermal and ambient noise, was measured in air using a Dimension 3100 Series scanning probe microscope (SPM), and in certain cases, a Polytec MSV300 laser Doppler vibrometer. The sensors were used to detect the mass of Listeria innocua bacteria by applying increasing concentration of bacteria suspension on the same cantilever beams and measuring the resonant frequency changes in air. Cantilever beams were also used to detect the mass of proteins such as Bovine Serum Albumin (BSA) and antibodies for Listeria that were attached to the cantilever's surfaces by physical adsorption; following which they were used to capture and detect the mass of the bacterial cells on the functionalized cantilever beam surfaces'. The effects of critical point drying of the proteins were evaluated and the results indicate that the functionality of the antibodies was not reduced once rehydrated after critical point drying. The developed biosensor is capable of rapid and ultrasensitive detection of bacteria and promises significant potential for the enhancement of microbiological research and diagnostics.

Nonmonotonic Energy Dissipation in Microfluidic Resonators

“…DOI: 10.1103/PhysRevLett.102.228103 PACS numbers: 87.85.Qr, 81.07.Àb, 85.85.+j Micro-and nanomechanical cantilevers are widely used as sensitive probes for physical measurements in materials science, engineering and biology. In vacuum and air, detecting shifts in the resonance frequency enables exquisitely sensitive measurements of mass and detection of single DNA molecules, single viral particles, and single bacterial cells [1][2][3][4]. However, numerous applications in nanotechnology and the life sciences require samples to be contained in liquid.…”

High-Sensitivity Polarization-Independent Biochemical Sensor Based on Silicon-on-Insulator Cross-Slot Waveguide

“…However, it should be noted that any CMOS compatible material, such as Si 3 N 4 [14], can also be used to fabricate the initial slot regions, which later on needs to be selectively removed to open up the empty slot region. Previously, sensing arm of several micron long incorporating cantilever suspension from one end has been fabricated with negligible deformation [15]. However, since for the proposed structure only a short length of slot waveguide is suspended from both the ends it is expected to be mechanically sturdier.…”

Device for filamentous fungi growth monitoring using the multimodal frequency response of cantilevers

“…[18][19][20][21][22][23][24] In the field of microbiology, studies have successfully demonstrated their use as mass sensors for pathogen detection via antibody-antigen chemistry. [25][26][27] Techniques moving away from antibody-antigen immobilisation have also been reported with the detection of yeast cells (Saccharomyces cerevisiae (S. cerevisiae)) using poly-L-lysine, 28 and the detection of Escherichia coli (E. coli) using cantilevers functionalised with mannosides. 29 These techniques also suffer from live/dead cell discrimination issues.…”