1. First Blueprint, Now Bricks: DNA is nanoscale construction material. Yamuna Krishnan The Chemical Biology Group National Centre for Biological Sciences, TIFR Bangalore 560 065, India yamuna@ncbs.res.in TIFR

2. Structural DNA Nanotechnology 2 nm 3.4 nm x 2 Adenine Guanine Thymine Cytosine Persistence length = 150 bp; 50 nm

3. Reciprocal exchange

4. A tomic F orce M icroscope imaging

5. Structures in 2D : Arrays Mao, C. et al, J. Am. Chem. Soc. 1999, 121, 5437 What can we build with this brick? Sequence of A,G,T & C = a string/seqence = DNA sequence is crucial. Each sequence must be unique = unique string. A unique sequence has a unique partner – exact complement Change of properties from single strand to duplex

6. Triangular and Pseudohexagonal 2D arrays 200X200 nm Liu et al, J. Am. Chem. Soc. 2004, 126, 2324 Ding et al, J. Am. Chem. Soc. 2004, 126, 10230 1.2  m