Determining the Physical Properties of DNA in Microarrays Using Optical Tweezers

1. Determining the Physical Properties of DNA in Microarrays Using Optical Tweezers Megan McDonald1,2, A. Malcolm Campbell1, Dan Boye2 1Biology & 2Physics Depts., Davidson College, Davidson, NC Optical Tweezers Design Introduction DNA microarrays measure genome activity in cells. DNA is attached to amino-modified glass slides through UV-induced covalent bonds, and fluorescent DNA is used to reveal mRNA production. To date, no one understands the physical properties of DNA attached to glass, which would certainly affect the outcome of the microarray. Optical tweezers can be used to determine physical properties. The colors depict the ratios of expression for each gene. Predictions The chemistry of DNA covalently bound to glass Coupling Beads to DNA Principles of Optical Tweezers Predicted DNA force pattern from optical tweezers. Currently Isolated a 977kb fragment of the FMR1 gene, to attach to beads Integrated new photodetector system into optical tweezers setup Optimized solution for suspending beads, to prevent sticking to slide. Created aldehyde-functionalized beads from amines using glutaraldehyde. LabVIEW code for calibration, data acquisition, & movement in x-y plane Future Work Calibration of system with photodetector, new solution, and 1μm beads UV-link DNA to glass slide and attach bead to DNA Measure strength of DNA bound to glass Combine force data with known sequence of DNA Attempt to determine the structure of the bound single-stranded DNA. memcdonald@davidson.edu Research funded by the National Science Foundation and the Bank of America