Ultrasensitive Pathogen Quantification in Drinking Water Using Highly Piezoelectric PMN-PT MicrocantileversEPA Grant Number: R829604
Title: Ultrasensitive Pathogen Quantification in Drinking Water Using Highly Piezoelectric PMN-PT Microcantilevers
Investigators: Shih, Wan Y. , Lee, Y. , Mutharasan, R. , Shih, W.-H.
Current Investigators: Shih, Wan Y. , Mutharasan, R. , Shih, W.-H.
Institution: Drexel University
EPA Project Officer: Lasat, Mitch
Project Period: January 1, 2002 through December 31, 2004 (Extended to December 31, 2005)
Project Amount: $449,713
RFA: Exploratory Research: Nanotechnology (2001) RFA Text | Recipients Lists
Research Category: Safer Chemicals , Nanotechnology
The goal of proposed research is to use highly piezoelectric microcantilever arrays for in-situ rapid simultaneous multiple pathogen quantification in source water with the ability to detect pathogens using electrical means with unprecedented sensitivity (10-15g). The proposed piezoelectric microcantilevers with antibodies specific to the target pathogens immobilized at the cantilever tip will measure the presence of pathogens with femtogram (a small fraction of a cell's mass) sensitivity in source water. This represents the ability to detect a single cell. We will demonstrate the use of the highly piezoelectric microcantilever for simultaneous quantification of model pathogens, Cryptosporidium parvum, Helicobacter pylori and Escherichia coli 0157.
The device consists of a highly piezoelectric lead magnesium niobate-lead titanate solid solution (PMN-PT) cantilever smaller than 10 p.m in length coupled to antibody proteins immobilized at the cantilever tip. Binding of target pathogens is detected by monitoring the resonance frequency shift. The resonance frequency shift transient can be used to characterize the amount of pathogens present in the drinking water. Typical drinking water contains a few pathogens in a liter. Because of the small size, the proposed PMN-PT microcantilever is capable of single bacterium detection in a small volume. In the initial step, we will test the device by concentrating pathogens in drinking water to a small volume, 400 pl, which allows for faster detection. The concentration in the small volume will be determined from the transient and correlated with the concentration in drinking water. Ultimately, we will quantify the pathogen concentration directly in drinking water. Because the proposed piezoelectric cantilever sensors use electrical signal for actuation and detection, the sensor and all necessary electronics can be organized in a compact form and easily usable in such broad ranging applications as environmental monitoring and genomics-inspired proteomics. The proposed study is both a beneficiary and an enabling technology involving nanometer scale engineering: (i) the fabrication of the extremely highly piezoelectric but difficult to make PMN-PT thin layers involves coating Mg(OH)2 nanolayers on nanometer-size niobium oxide particles; and (ii) the proposed sensor offers the unprecedented ability to detect and manipulate a nanometer-size object, a single pathogen in water.
There is an immediate need for rapid, quantitative, and specific pathogen detection to ensure the safety of natural and manmade water supplies, including source, treated, distributed and recreational waters. It is anticipated that as a result of the proposed study, ultrasensitive, rapid, specific, multiple pathogen quantification of drinking water will be achieved using arrays of highly piezoelectric PMN-PT unimorph microcantilevers of less than 10pm in length with better than 10 g/Hz sensitivity coupled with antibodies specific to the target pathogens immobilized at the cantilever tip.