|Exposure of the porous Si/hydrogel nanostructure to
At the Technion’s Faculty of Biotechnology and Food Engineering, Dr Ester Segal and her graduate students, Naama Massad-Ivanir and Giorgi Shtenberg, have developed an innovative method for rapid detection and quantification of bacterial contaminations in water. The nanoscale technology relies on a silicon-based hybrid that targets and captures the bacteria.
the target bacteria results in “direct cell capture” onto
the biosensor surface, detected via predictable
changes in the light reflected from the surface
Using existing methods for detecting harmful bacteria contaminations, scientists must collect samples in the field, and then return to a lab to culture them for analysis - a process that takes a minimum of 24 hours. The identification and quantification in the lab, while accurate, requires a lot of time, skilled manpower, and the use of complex and expensive equipment.
With the novel in-the-field rapid-detection method, the researchers are able to analyze bacterial concentrations within minutes. The findings were published in Advanced Functional Materials.
The Technion team drilled nanometer-sized holes in silicon wafer using a simple electrochemical reaction. “The resulting perforated chip displays typical optical characteristics in the range of visible light,” explains Segal. “We attach a polymer arm to the chip, which serves to connect specific antibodies to the bacterium. This special structure traps bacteria on the silicon surface. The ‘trapped’ bacteria cause changes in the light spectrum reflected back from the chip, enabling us to determine its concentration in real time.”
The new method represents a field-portable alternative to more expensive procedures, particularly where larger-scale, expensive equipment is not readily accessible. This method can also be efficient against biological terror threats and for identifying contaminants in drinking water, food, and the environment.
The research was supported by the Technion’s Russell Berrie Nanotechnology Institute, Center for Security Science and Technology, and the Israel Science Foundation. In 2009, Giorgi Shtenberg received the Seiden Family Prize for Multidisciplinary Undergraduate Student Projects in Optoelectronics, Microelectronics and Nanosciences for preliminary work on this project.