Supporting Information

Transcription

1 Supporting Information Thermal Stability of DNA Origami on Mica Michelle A. Pillers and Marya Lieberman* Table of Contents: Page 1. Additional AFM Images 2 2. Nanostructure Height Determination and Counting Procedures 5 3. Lateral Dimension Measurement Procedures 6 4. Fine Structure Measurement Procedures 7 5. Additional XPS Spectra and Element Ratios 9 1

2 Additional AFM Images: Figure S1. AFM control images of unheated DNA origami on mica. 2

3 Figure S2. AFM images of DNA origami heated on mica to 150 C for 15 minutes. 3

4 Figure S3. AFM images of DNA origami heated on mica to 150 C for 45 minutes. 4

5 Figure S4. AFM images of DNA origami on mica heated to 250 C for 15 minutes. Nanostructure Height Determination and Counting Procedures: Height and nanostructure count were determined using the "Particle Analysis" tool of Bruker NanoScope Analysis software. The threshold height was determined by visual inspection of the complete coverage of all nanostructures (figure S5); the program then calculated the average height and total number of isolated nanostructures. Due to the random nature of the DNA origami adhesion to the mica surface, it is possible that two or more nanostructures could be placed close enough that the program is unable to differentiate the structures. This would cause the several "clumped" nanostructures to be counted as a single structure; taking this into account, it is possible that the total nanostructure counts reported in 5

6 this study were lower than the actual number of nanostructures in the image. However, this fact would not interfere with the average height calculations. Figure S5. A screen shot of the "Particle Analysis" tool in the NanoScope Analysis software. The blue areas on the AFM image indicate nanostructures with heights that are within the determined "Threshold Height" and are the nanostructures included in the total count and average height measurements. Lateral Dimension Measurement Procedures: The height and width of the DNA origami rectangles were determined using the "Section" tool of the NanoScope Analysis software. The lengths and widths of each rectangle were measured independently. The edges of each rectangle were determined visually. The dimensions were measured at the approximate center of each side. 6

7 Figure S6. A screen shot of the "Section" tool in the NanoScope Analysis software. Lines were drawn across each structure to measure the topography in that specific direction. From the topographical information, the edges of the structure can be approximated and the distance between each edge (i.e. the lateral dimensions) were determined. This procedure was repeated for all measured nanostructures. Fine Structure Measurement Procedures: The DNA origami used contained two fine structure details that allowed for a better understanding of the thermal stability of smaller structural components. The fine structure details can be seen in figure S7; included is a small loop composed of single-stranded DNA and an "L" comprised of staple strands that form bulky hairpin turns. The "L" fine structures are present on both sides of the DNA origami and should be visible independent of orientation of the nanostructures of adhesion to the mica surface. AFM images were visually inspected and the fine structures of each nanostructure counted in each image. The presence of the fine structure details was highly dependent upon image quality. This caused variability in the percentage of fine details determined for unheated samples and samples heated to 150 C for 15 and 45 minutes. However, all images contained some fine structure detail; this was not the case for any sample heated to 250 C, where there was no evidence of any fine structure detail. 7

8 B A Figure S7. An AFM image illustrating examples of the fine structure details in the DNA origami nanostructures used in this experiment: A) the small loop of single-stranded DNA; B) the letter "L" on the top surface of the DNA origami created by staple strands that form bulky hairpin turns. 8

9 Additional XPS Spectra and Element Ratios: Figure S8. XPS spectra of the C1s regions (284 ev) and K2p regions (K 2p 3/2 peak at ev and K 2p 1/2 peak at ev) for A) unheated mica substrate, B) mica substrate heated to 150 C for 10 minutes, and C) mica substrate heated to 250 C for 10 minutes. 9

10 Figure S9. XPS spectra of the Ca 2p regions (349 ev) and K2s regions (376.5 ev) for A) unheated mica substrate, B) mica substrate heated to 150 C for 10 minutes, and C) mica substrate heated to 250 C for 10 minutes. 10

11 Figure S10. XPS spectra of the Si 2s regions (152 ev) for A) unheated mica substrate, B) mica substrate heated to 150 C for 10 minutes, and C) mica substrate heated to 250 C for 10 minutes. 11

12 Figure S11. XPS spectra of the C1s regions (284 ev) and K2p regions (K 2p 3/2 peak at ev and K 2p 1/2 peak at ev) for A) unheated DNA origami on a mica substrate, B) DNA origami on a mica substrate heated to 150 C for 10 minutes, and C) DNA origami on a mica substrate heated to 250 C for 10 minutes. 12

13 Figure S12. XPS spectra of the Ca 2p region (349 ev), K2s region (376.5 ev), and N 1s region (398.5 ev) for A) unheated DN origami on mica substrate, B) DNA origami on mica substrate heated to 150 C for 10 minutes, and C) DNA origami on mica substrate heated to 250 C for 10 minutes. 13

14 Figure S13. XPS spectra of the Si 2s regions (152 ev) for A) unheated DNA origami on mica substrate, B) DNA origami on mica substrate heated to 150 C for 10 minutes, and C) DNA origami on mica substrate heated to 250 C for 10 minutes. 14

15 Table S1. Relative ratios of elemental components for various samples. All mica control ratios have a sample size of N=2; all DNA origami on mica ratios have a sample size of N=3. Sample C1s(A):K2p3/2 C1s(B):K2p3/2 C1s(C):K2p3/2 N1s:K2p3/2 Mica Control 1.66±0.31 N/A N/A N/A (Unheated) Mica Control 1.64±0.41 N/A N/A N/A (150 C) Mica Control 1.33±0.21 N/A N/A N/A (250 C) Mica+DNA ± ±2.70 0±0 0.89±0.27 (Unheated) Mica+DNA ± ± ± ±0.31 (150 C) Mica+DNA ± ± ± ±0.03 a) (250 C) a) Sample size N=2. 15