In an ideal world, a physician would be able to diagnose any disease as easily as a patient’s body temperature is determined. In the case of cancer, such diagnostic tools are presently only a dream. Our team is reaching for that goal, however, borrowing techniques used by the electronics industry to manufacture items such as computers and cell phones to make devices that may one day be used by a physician to quickly diagnose disease and to determine a patient’s response to treatment such as chemotherapy. The technologies we are using are referred to as microfluidics and nanofluidics. They are analogous to microelectronics and nanoelectronics except that the fluidic devices contain tiny pipes rather than electrical wires. Our diagnostic devices accept small samples of material such as a drop of blood or tissue collected with a small needle. They separate cancerous cells from other types of cells and perform sophisticated analyses on the contents to determine whether the cells are functioning abnormally or not. We are designing these devices to be simple to use by a clinician and to return results within the time frame of an office visit. The small sample requirements will reduce discomfort for the patient and the fast response times will assure that a treatment regime if necessary is implemented as soon as possible. The devices will also allow the effectiveness of a course of the treatment to be easily followed.
Research Summary
A critical problem in cancer care is the inability to provide rapid diagnostic or prognostic information for a patient using conveniently accessible sample materials. To address this issue, we are developing point-of-care microfluidics platforms that accept “as collected” patient samples and provide relevant biochemical information to the clinician within 30 - 60 min. We are presently utilizing whole blood samples collected from a finger stick, but also envision the use of needle biopsies in the case of solid tumor samples. The microfluidics devices will include sample processing to reduce complexity, a micro-flow cytometer for isolating targeted cell types, and nanotechnology-based biochemical assays to determine biochemical function in the isolated cells. The molecular data obtained from the patient’s samples will provide biomolecular information relevant to disease diagnosis and the efficacy of therapeutic treatment. Our initial efforts have concentrated on the analysis of finger stick whole blood samples for the enumeration of T-regulatory cells. We have demonstrated the ability to efficiently isolate leukocytes from whole blood samples and to then identify T-lymphocytes using an integrated flow cytometer. Specific cells can be lysed based upon the flow cytometry information. Two different approaches are being explored for quantifying cellular proteins. One technique involves the integration of molecular Coulter counting with antibody recognition. This technique involves the implementation of molecular scale Coulter counting where the nanopores are decorated with antibodies for specific target proteins. Cellular protein quantification will be determined by monitoring ion current through arrays of nanopores. The second strategy under development for cellular protein detection involves the formation of a spatially patterned array of antibodies contained in a microchannel. The target proteins are quantified using a fluorescence sandwich immunoassay. We are initially targeting the cellular protein FoxP3 for identification of T-regulatory cells, an important T-cell subset that presently cannot be identified by flow cytometric means using viable cells. Other cellular protein targets include phospho-ERK, Src, and Cdc42 concentrations—all targets of known relevance in cancer biology.
Nanofluidic Devices
