Overview
This project will develop self-contained biochips capable of rapidly measuring expression levels of a hundred or more genes (identified by the Functional Genomics and Bioinformatics Cores) that will define radiation exposure, dose and injury. This approach will only require a drop of blood from a finger prick, and will be readily deployable for large-scale population screening in the event of a radiological incident. In order to accomplish this, our team will analyze a set of specific genes for changes that indicate radiation exposure. Exposure to ionizing radiation produces dose-dependent changes in the expression of many genes, potentially providing a means to assess both radiation exposure and dose.
Project Aim
There is persuasive evidence that exposure to ionizing radiation produces a well-defined dose-dependent signature in terms of changes in gene expression. Our overall goal is to use such a signature, which will be established through the Functional Genomics Core, to "generate a self-contained radiation biodosimeter product, based on blood collected from a finger stick". We are in the process of developing a completely self-contained, fully integrated biochip device that consists of microfluidic mixers, valves, pumps, channels, chambers, heaters, and DNA microarray sensors to perform DNA analysis of complex biological sample solutions, such as blood. Sample preparation (including magnetic bead-based cellcapture, cell preconcentration and purification, and cell lysis), DNA hybridization, and detection can be performed in this fully-automated miniature device.
Integrated mixing methods are used to overcome diffusion limitation at the micro-scale, and to enhance target cell or total RNA capture from whole blood samples and to accelerate the DNA hybridization reaction. Thermally actuated paraffin-based microvalves are used to regulate liquid flow. Electrochemical pumps and thermopneumatic pumps are integrated on the chip to provide liquid handling.
The devices, fabricated by micro-machining, injection molding and imprinting methods using polymeric materials, are easy and inexpensive to manufacture. Based on this technology we are developing a self-contained radiation biodosimeter product, using blood obtained from a finger stick, which will allow one to perform genetic testing at point-of-care sites.
While the technology exists to perform highly sensitive and accurate gene-expression analysis using bench-top instrumentation and skilled technicians, there is no portable, inexpensive and rapid instrument that automates these processes. The goal of this project is to fabricate a self-contained, fully integrated cartridge that autonomously performs the complete gene-expression bio-assay. The cartridge will contain its own power source, control electronics, functional microfluidic components and reagents. After assay completion, the cartridge is inserted into a modified commercial reader where the signal is read out within seconds. In emergency situations, thousands of such cartridges could be used in parallel for high-throughput screening of affected populations.
The cartridge will be developed using fabrication processes which ensure that scaling up of the production by an industrial partner is easily possible. The Center for Applied Nanobioscience has access and expertise in large scale production through its affiliation with the Center for Flexible Display.
Design and study of biodosimeter
Prepared as part of the preparation for the Coyote Exercise 2006, a disaster preparedness exercise held in the City of Scottsdale with industrial, military and civil participants.
Highlights of this project are to:
Develop a module for the collection of blood from a finger prick.
Fabricate and validate microfluidic systems with integrated oligonucleotide arrays.
Develop and performance-test an integrated micro/nano fluidic cartridge for extraction and processing of RNA from whole blood.
Incorporate the radiation-related gene-expression signature identified by the Functional Genomics Core into customized microfluidic micro-arrays.
Integrate the blood sample collection device, the RNA extraction device and the hybridization microchannel device into a single self-contained biochip, and validate the performance of this biochip.
Integrate and evaluate reagent storage options for the self-contained cartridge.
Develop integrated control electronics, creating a portable instrument suitable for mass-production and application to high-throughput screening, and verification that this device meets product requirements.
Sample preparation cartridge
The technology that processes blood to test for radiological contamination is housed in the sample preparation cartridge. The cartridges work in tandem with a rack system, into which the cartridges are inserted for processing, in order to read out, store and transmit test results. The cartridges process a single sample of blood at a time, but are designed to be reusable when required.
Physical Form
The casing of the cartridge is rigid and strong to protect inner technology from handling, environmental factors, etc.
The shape of the cartridge is organic to prevent the accumulation of dust and other particulates from the air, due to radiation.
Indentations are part of the aesthetic of the cartridge and suggest proper thumb placement.
A ridge provides a grip for a technician to be able to hold onto the cartridge even while wearing gloves.
The
purpose of the rack is to organize the cartridges while they are processing
the radiological information. Once the processing is finished, an internal
wireless system transmits the data to the healthcare center.
