| AVS 57th International Symposium & Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI2-WeM |
| Session: | Proteins & Peptides on Surfaces |
| Presenter: | L.J. Gamble, University of Washington |
| Authors: | L.J. Gamble, University of Washington N. Vandencasteele, University of Washington L. Arnadottir, University of Washington D.G. Castner, University of Washington D.W. Grainger, University of Utah |
| Correspondent: | Click to Email |
Commercial DNA array slides are commonly made by microprinting techniques. These nanoliter doplets evaporate within seconds and this fast drying may contribute to heterogeneous spots and inconsistent results. Successful development and optimization of DNA-functionalized surfaces for microarray and biosensor applications requires a better characterization of immobilized DNA. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) is applied to the study of spotted DNA surfaces on commercial microarray slides. ToF- SIMS results are directly compared to fluorescence images. Maximum Autocorrelation Factor (MAF) image analysis, a technique independent of the scaling of the raw data, is used to analyze the ToF-SIMS images. An IONTOF TOF.SIMS 5-100 instrument using a Bi source is used to analyze the samples. Immobilized DNA probes with 10, 20 and 40μM DNA concentrations as well as different Cy3 label concentrations are spotted on a commercially available microarray polymer slide. The effect of the spotting solution concentration as well as the amount of Cy3 label on spot uniformity is studied. MAF analysis of the ToF-SIMS image for a 20μM DNA spot shows that the areas seen as having high fluorescence intensities are related to higher concentrations of phosphate groups (from the DNA backbone) as well as sulfates and peaks with masses corresponding to the DNA bases. A comparison of MAF analysis of ToF-SIMS images for different DNA spotting concentrations indicates that the concentration of the spotting solution has an effect on the uniformity of the spot.