Biosensor based on a microelectromechanical system integrated with a photodetector

March 3, 2014
Figure caption: (a) Schematic image of the label-free biosensor based on a MEMS Fabry–Perot interferometer. (b) Schematic diagram of the transmission spectrum of the Fabry–Perot interferometer on the biosensor. (c) Photograph of the developed MEMS Fabry–Perot interferomtric biosensor.

Label-free biosensors can be applied in many processes such as rapid diagnosis, tailor-made medication, and drug discovery. Label-free microelectromechanical system (MEMS)-based sensors detect target molecules by measuring the deflection of cantilevers caused by biomolecular adsorption.

However, it suffers from poor sensitivity because of the low conversion efficiency of linear transducing from the mechanical deflection to the readout signal.

Kazuhiro Takahashi and colleagues at Toyohashi University of Technology have developed a biosensor based on a MEMS Fabry–Perot interferometer integrated with a photodiode, which utilizes the nonlinear optical transmittance change in the Fabry–Perot interference to enhance the sensitivity. The theoretical minimum detectable surface stress of the proposed sensor was predicted to be -1 µN/m, which is two orders of magnitude greater than that of the conventional MEMS sensor.

The Fabry–Perot sensor was fabricated using a 4-inch p-type silicon wafer. The photodiode was integrated into the silicon substrate using ion implantation of phosphorus. Sacrificial polysilicon was isotropically etched to form a freestanding membrane. Amino-methyl-functionalized parylene was coated on the membrane for immobilization of the biomolecules via electrostatic coupling.

After immobilizing anti-bovine serum albumin antibodies, the photocurrent change of 23.7 nA was measured, whereas no current shift was observed in the initial photocurrent as compared with that after washing with buffer solutions.

The MEMS Fabry–Perot interferometric sensor allows the use of a universal biochemical sensing platform in a label-free manner.

Explore further: Highly sensitive graphene biosensors based on surface plasmon resonance

More information: Kazuhiro Takahashi, Hiroki Oyama, Nobuo Misawa, Koichi Okumura, Makoto Ishida, and Kazuaki Sawada. "Surface stress sensor using MEMS-based Fabry-Perot interferometer for label-free biosensing." Sensors & Actuators B 188, 393-399 (2013). (DOI): 10.1016/j.snb.2013.06.106

Related Stories

Tiny sensors put the squeeze on light

October 24, 2013

Microelectromechanical systems, known as MEMS, are ubiquitous in modern military systems such as gyroscopes for navigation, tiny microphones for lightweight radios, and medical biosensors for assessing the wounded. Such applications ...

Microtechnology: Double-layer capping solves two problems

January 15, 2014

Continual downsizing of technology means that researchers have to develop ever more ingenious methods of packaging and protecting their tiny devices. Jae-Wung Lee and co-workers at the A*STAR Institute of Microelectronics, ...

Pencil drawing of a sensor actually is a sensor

February 28, 2014

Using graphite pencils to draw on regular paper, researchers can make some very inexpensive piezoresistive (PZR) sensors. Due to the piezoresistive effect, a sensor's resistance changes under an applied strain, allowing it ...

Recommended for you

Inferring urban travel patterns from cellphone data

August 29, 2016

In making decisions about infrastructure development and resource allocation, city planners rely on models of how people move through their cities, on foot, in cars, and on public transportation. Those models are largely ...

How machine learning can help with voice disorders

August 29, 2016

There's no human instinct more basic than speech, and yet, for many people, talking can be taxing. 1 in 14 working-age Americans suffer from voice disorders that are often associated with abnormal vocal behaviors - some of ...

Apple issues update after cyber weapon captured

August 26, 2016

Apple iPhone owners on Friday were urged to install a quickly released security update after a sophisticated attack on an Emirati dissident exposed vulnerabilities targeted by cyber arms dealers.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.