The overall goal of this Phase I SBIR project is to establish the feasibility of using a novel antibody-coated microfluidic device to capture fetal cells from samples of peripheral maternal blood for the purpose of noninvasive prenatal diagnosis. Genetic abnormalities affect 1 in 200 births and represent a major health care and societal problem. There is a critical unmet need for a definitive non- invasive method to obtain fetal cells for genetic diagnosis in the first trimester of pregnancy. Fetal nucleated red blood cells are found in the maternal circulation at frequencies as low as 10'9 as early as the first trimester of pregnancy. These cells contain a full complement of nuclear genes and hence represent an excellent cell source material for prenatal diagnosis. Living Microsystems has developed a high-speed microfluidic platform that uses immunoaffinity capture to selectively recover both model cell lines and fetal cells from whole blood with frequencies as low as 10"8. Preliminary studies demonstrated that the captured cells can be analyzed by immunocytochemistry and fluorescence in situ hybridization (FISH). The objective of this Phase I SBIR feasibility study is to improve device design and performance to enable the capture of a model population of rare cells that have been spiked into whole blood at a frequency of one in 109 with >80% yield. Aim 1 will implement microfabricated devices with geometries that are optimized by fluidic modeling to enhance capture of rare cells from blood. Aim 2 will identify the microfluidic flow rate, blood dilution ratio and antibody immobilization chemistry that maximizes recovery of labeled target cells that have been spiked into whole blood. Successful completion of this work will lead to a Phase II proposal to validate microfluidic capture and molecular analysis of circulating fNRBCs in pre-term maternal blood. This proposal addresses an important clinical problem: recovery of fetal cells for prenatal genetic diagnosis in the first trimester of pregnancy. Each year, more than 500,000 pregnant women are evaluated for high-risk pregnancies and <2% of the fetuses evaluated are found to carry a chromosomal abnormality. The development of a low-risk, minimally invasive definitive method for genetic analysis would be a highly innovative and important advance in prenatal medicine
