Question

Ch.11- 2.   Read the article on DNA origami article ( DNA Origami: The Art of Folding DNA Barbara Sacc* and Christof M. Niemeyer)

Answer each of these questions using 100-150 words

                  A. What is DNA origami? What has it been used for?

                  B. What are “staple strands” and how are they used?

                  C. How can lattices be built in three dimensions?

D. Do a citation index search of publications that reference this paper. What is the most recent citation that uses DNA origami for building novel structures?

Answer 1

A. Definition: DNA origami is the nanoscale folding of DNA to create non-arbitrary 2-D and 3-D shapes at the nanoscale.

Uses: There were a number of applications from drug delivery systems to use as circuitry in plasmonic devices; however, most applications remain in a concept or testing phase.

B. Definition: DNA origami works by using a long "scaffold" strand of viral DNA and holding it together using 200-250 base strands called staple strands. The origami is formed by a researcher using enzymes to cut DNA in certain places on a 5,000-10,000 base strand, inducing the cut pieces into parallel positions and making crossovers, and then using the staple strands to strengthen the structure.

Uses: Staple strands that create DNA origami structures laced with doxorubicin, a powerful cancer drug, were extremely effective at killing tumor cells that had previously developed a resistance to the drug. The researchers suggest that their DNA nanostructures were the ability to circumvent the drug resistance of these cancer cells by increasing the cellular uptake of doxorubicin and inducing a change in lysosomal pH that redistributed the drug to target sites.

C. A 3-D lattice can be built by adding a third unit vector, c, to the unit vectors, a and b, which define the unit cell of the 2-D lattice. The unit cell of a 3-D lattice takes the general shape of a parallelepiped.

As in the 2-D case, the entire crystal lattice can be constructed by repeating these unit vectors indefinitely, a 3-D structure or crystal is created by adding a basis to each lattice point.