AVS 50th International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI+SS-WeA

Paper BI+SS-WeA9
Arrays of DNA-tagged Vesicles Based on Spontaneous Sorting to a DNA-array Template

Wednesday, November 5, 2003, 4:40 pm, Room 307

Session: Biomolecular Surface Science and Microfluidics
Presenter: I. Pfeiffer, Chalmers University of Technology, Sweden
Authors: I. Pfeiffer, Chalmers University of Technology, Sweden
S. Svedhem, Chalmers University of Technology, Sweden
F. Höök, Chalmers University of Technology, Sweden
Correspondent: Click to Email
We have developed a surface-modification protocol that allows sorting of DNA-tagged vesicles (where DNA is anchored via a cholesterol moiety) to arrays of cDNA-modified Au-spots on a SiO@sub 2@ surface. Biotinylated albumin (biotin-BSA) was chosen to functionalize Au spots surrounded by SiO@sub 2@, while supported phospholipids bilayers was formed on the surrounding SiO@sub 2@, thus representing an inert background. This allowed subsequent coupling of biotinylated DNA strands via neutravidin bound to biotin-BSA only on Au spots. Eventually, a cDNA array created in this way was proven compatible with specific immobilization of differently DNA-tagged vesicles utilizing complementary DNA hybridization. The surface functionalization protocol was established using the quartz crystal microbalance technique with dissipation monitoring (QCM-D), allowing quantification of the different immobilization steps, while fluorescence microscopy was used to analyze the vesicle sorting. The compatibility of the vesicles to act as carriers for proteins was proven using scFv-antibodies, anchored to the DNA-tagged vesicles via nitrilotriacetic acid (NTA)-functionalized lipids. These results thus open up the prospect to use surface directed sorting of functionalized vesicles for construction of protein arrays, avoiding complicating and/or destructive microfluidics or microdispensing protocols. The work also includes a number of alternative approaches towards the creation of DNA arrays being compatible with the above described principle for spontaneous vesicle sorting, including improvements in the strength of the cholesterol-DNA based coupling and the dimension of the arrays, which has the potential to be down-scaled to the length of the DNA probes and the size of the vesicles, typically being less than 100 nm.