Metamaterials Incorporated On Paper To Make Biomedical Sensor

‘Paper’ is being used nowadays in almost all areas of human civilization. It is used for writing, cleaning, as news paper, for carbon copying documents and what not! It is also used as a sensor in many applications. However, speaking of technology, a professional user always experiences a difference between the conventional sensors and the paper sensors. The conventional ones have higher sensing capabilities and a superior resolution than their paper counterparts. To solve the resolution difficulties, a group of researchers from Boston and Tufts University led by Hu (Tiger) Tao have recently incorporated high resolution metallic resonators on paper.
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The researchers have successfully developed techniques to integrate metamaterials on paper. It is a big step ahead for incorporating any electromagnetic sensor on paper. Tao’s team used Gold as their target material on paper substrate using a 500 nanometer thick silicon nitride film microstencil-based shadow mask. The next steps of the process proceed under a dry and chemical less environment. A 150 nanometer Gold layer is then sprayed on paper substrate with the help of Electron beam evaporation technique, with microstencil still in touch with paper substrate. In this whole process, Tao’s team used a paper of surface roughness around 18 nanometers.
The scientists also tried to test their new sensor successfully by subjecting it to real life situation at laboratory level. So, the researchers subjected the sensor to varying concentrations of Glucose and tested it for a change in analyte induced resonance. The team observed a continuous change at a resonant frequency of 908GHz for increasing concentrations of Glucose.
The current research is important owing to the fact that the existing biosensors show only a color change that too of a specific antigen. The metamaterial based biosensor operates senses data at a greater scale. It also exhibits sensing a radio frequency property along with normal functions of a biosensor. Another reason was that, for obtaining high resolution on paper, people had to employ difficult techniques of photolithography.
The work of Tao’s team is published in the online edition of Advanced materials under the title “Metamaterials on paper as a sensing Platform”.
Source: Paper-based metamaterial biosensor