DNA Repair-on-a-Chip: Spatially Encoded Microwell Arrays

Project Summary / Abstract Preserving genomic integrity is essential in order to suppress cancer, neurodegeneration, aging and other diseases. At odds with genomic preservation is DNA damage, which can drive mutations, sequence rearrangements and cellulartoxicity. DNA damage is unavoidable, as DNA damaging agents are present in our environment and in our cells. To counteract the deleterious effects of DNA damage, we have evolved sophisticated DNA repair systems. It is now known that every major DNA repairpathway suppresses cancer. Furthermore, since cancer is often treated using DNA damaging agents, it is not surprising that the DNA repair capacity of tumors modulates sensitivity to chemotherapy. Despite its importance, measurements of DNA damage and repair are far from routine, primarily due to the lack of reliable and rapid DNA damage assays. Here, by bringing together convergent expertise among engineers, biologists and computer programmers, we propose to meet this need by developing a platform for rapidsemi- automated single-cell DNA damage quantification that can be broadly distributed and readily applied by researchers in public health, academia, industry and medicine. As defined in the Phase I submission, we created and tested a prototype for a 96-well CometChip platform and have optimized the engineering design and a production apparatus to produce spatially encoded 20 and 96 well demonstrated that supplementation of the Microwell Comet gels with extracellular matrix proteins (EMPs) supports the growth of human cells for up to two weeks and the EMPs do not impact the formation of comets. To enable characterization of the genotoxicity of chemicals used commercially, those found in the environment or newly developed pharmaceuticals, and to quantify DNArepair capacity without the need to identify specific DNA Repair technology. This proposal, to develop the 'DNA Repair on a Chip' technology, combines the use of agarose based Microwell arrays, spatially encoded cellular recognition, automated data processing, and extra-cellular matrix proteins to optimize, validate and commercialize a series of Spatially Encoded Microwell Arrays. We will demonstrate that we have significantly advanced the manufacturing process (Aim1), have developed a macrowell former toproduce 96-well and 384-welll CometChips (Aim 2), and propose the implementation of a graphical user interface for data analysis (Aim 3). Finally, we will rigorously validate this new technology by analyzing the genotoxic effects of a range of compounds from the NTP library for their impact on DNA damage and repair responses and to reveal inter-individual and inter-cell type variation in DNA damage responses (Aim 4). Through the integration of traditional methods in biology and engineering, the DNA Repair on a Chip platform described here represents a significant technological advance, providing high-throughput, objective, and quantitative measurements that have the potential to become a new standard in DNA damage analysis. PUBLIC HEALTH RELEVANCE PUBLIC HEALTH RELEVANCE: We describe a new methodology that provides for robust, high-throughput DNA damage and repair analysis by exploiting gravity capture of single cells into a Microwell array. DNA damage levels are revealed morphologically by single-cell gel electrophoresis. The Microwell array enables fully automated DNA damage and DNA repair measurement of multiple experimental conditions simultaneously. This technological advance opens the door to new strategies for drug discovery, genotoxicity testing, andenvironmental health research through objective, quantitative analyses.