Pathogen detection is of the utmost importance primarily for health and safety reasons. The most common problem encountered with current pathogen monitoring techniques is the inverse relationship between specificity versus sensitivity and speed. Current tools used for pathogen identification are accurate but require a vast amount of sample preparation time, typically from an experienced operator in a laboratory setting and therefore not suitable for environmental monitoring or clinical diagnostics applications. In order to confront this throughput challenge, complementary monitoring technology needs to be developed. Specifically, a platform capable of early warning trigger when biological pathogens have potentially been released into the environment
The work in this thesis falls into two main sections. The first section focus on integrated microfluidic preconcentrator with optical and electrical detection for pathogen detection, where we explore the suitability of an insulator based dielectrophoretic microfluidic device coupled with real-time optical and impedance detection schemes. Dielectrophoresis provides selective sample preconcentration, which is a necessary precursor for any accurate identification scheme. By using the method of superposition, theoretical models were developed to assess the velocity associated with the relevant forces and predict the voltages required to trap and concentrate particles. After a specified collection time for selective preconcentration, the dielectrophoretic concentrator releases the preconcentrated sample to a detection channel. If particles have been collected in the detection channel, the sensor triggers a signal to the end user indicating that the sample needs further analysis and sends the sample downstream for identification.
In the second section of this thesis, integrated microfluidic pulse generators on single cell analysis chips is described. For better understanding of neurological disorders, the transient nature of synaptic transmission requires experimental setups that can provide adequate temporal resolution that mimic synapse signal transduction. Theoretical models for the characterization of this microfluidic device were developed. In addition, I will present other designs leveraging the same principle for the kinetic analysis of cell physiology and high throughput screening of ligand-gated ion channels.
May 31, 2007
Sabounchi, P. (2007). Integrated Biophysical Microfluidic Platforms for Pathogen Detection and Single Cell Analysis. (n.p.): University of California, Berkeley.