Sadao Takabayashi1, William Klein1, Blake Rapp2, Elias Lindau1, Lejmarc Snowball1, Juan Flores-Estrada, Andres Correa, William B. Knowlton1,2, Bernard Yurke1,2, Jeunghoon Lee3 ,Elton Graugnard1 ,Wan

Kuang2, and William L. Hughes1,* 1Department of Materials Science & Engineering, 2Department of Electrical & Computer Engineering, 3Department of Chemistry & Biochemistry Boise State University, Boise, ID 83725

*EMAIL: WILLHUGHES@BOISESTATE.EDU

Maximizing Nanoparticle Attachment onto DNA Origami Nanotubes

3. METHODS

• M13mp18 and 170 staple strands were utilized to form

the DNA nanotube.

• The DNA mixture was annealed at 90˚C for 15min then

cooled to room temperature at the rate of 0.6˚C/min

followed by agarose gel filttraion.

• Nanotubes and AuNPs were combined in a ratio of 5

AuNPs per binding site. The mixture was then

annealed at 45°C for 41 min.

• The nanotube/AuNP solution was purified by agarose

gel electrophoresis to remove unbound AuNPs.

• AuNP arrays were imaged using a Digital Instruments MultiMode atomic force microscope (AFM).

• The number of attached AuNPs were manually counted

to determine the binding affinity of each design.

1. MOTIVATION High yield, proximal assembly of metallic nanoparticle arrays is essential

for near-field, diffraction-limited, opto-electronic applications.1 Nanoparticle

arrays, with controlled spacing, have been assembled onto DNA origami

nanostructures.2 Studies of quantum dot attachment using biotin have

shown that using multiple biotin tethers per binding site significantly

increases attachment yield.3 Extending this approach, here we report

multi-tether attachment yields for DNA functionalized gold nanoparticles

(AuNP), as well as AuNP /quantum dot (QD) heterostructures.

2. BINDING STRATEGIES

• One tether per binding site (1x), 2 tethers per binding site (2x), and 4

tethers per binding site (4x) were incorporated into DNA origami.

• The 1x and 2x designs adopted existing origami nanotubes2 while the

4x design required side-by-side dimerization of parallel nanotubes to

create a nano-optical rail (Fig. 1).

• Nanotubes were synthesized with 9 binding sites separated by 43 nm

(Fig. 2).

• The 1x, 2x, and 4x designs contained one of two randomly generated

binding site sequences; sequence α (5’-ACCAGTGCTCCTACG-3’) or

sequence β (5’-TCTCTACCGCCTACG-3’).

• AuNPs (10 nm diameter) were functionalized with 5’ thiolated

oligomers consisting of a 5 thymine spacer and sticky-end

complements (5’-TTTTTcα-3’ or 5’-TTTTTcβ-3’).

Figure 1: Schematics of binding site strategies for attaching DNA conjugated gold

nanoparticles to DNA origami nanotubes. The strategies explore AuNP attachment

yield versus the number of sticky-ends per binding site.

Figure 2: DNA origami schematics with 9 binding sites. The 1x and 2x structures

contained a single nanotube, while the 4x structure contained side-by-side dimerization of two parallel DNA nanotubes to create a nano-optical rail.

43nm

412nm

1x, 2x

4x

1x Tether 2x Tether 4x Tether

7. SUMMARY • The 4x binding strategy demonstrated near 100% AuNP attachment onto DNA origami nanotubes with a 45nm binding site periodicity.

• The αβ structure showed successful attachment of AuNPs onto DNA origami nanotubes

without site bridging, as well as minimizing site periodicity to 14nm.

• The AuNP / QD heterogeneous structure showed successful AuNP and QD attachment

on the origami nanotube with 14nm binding site periodicity utilizing TEM and EDS for

particle analysis.

This project was supported in part by the: (1) NSF Grant No. CCF 0855212, (2) NSF IDR No. 1014922, (3) NIH Grant No. P20 RR016454 from the INBRE Program of the National Center for Research Resources, (4) NIH

Grant No. K25GM093233 from the National Institute of General Medical Sciences, (5) W.M. Keck Foundation Award, (6) Micron MSE PhD Fellowship, (7) LSAMP Grant No. HRD 0901196. We thank Helen Barnes, Greg

Martinez and Emily Flores; Coordinators of the McNair Scholars Program and LSAMP, respectively. Also we would like to thank the students and staff within the Nanoscale Materials & Device Research Group

(nano.boisestate.edu).

ACKNOWLEDGMENTS: REFERENCES: [1] K. Kelly et al., J. Phys. Chem. B, 107, 668 (2003) [2] H. Bui, et al., Nano Lett. 10, 3367 (2010). [3] S.H. Ko, et al., Adv. Func. Mater. 22, 1015 (2012)

4. BINDING STRATEGY YIELDS • Attachment yields for the three binding site strategies

are shown in Fig.3. As the number of tethers per

binding site increased the attachment yield increased.

• The 4x α and 4x β structures had the highest probability

of attachment (~1) and the lowest standard deviation.

Figure 3: AuNP attachment yields of various structural designs for

the binding strategies shown in Fig. 1 and implemented on the

nanotube designs in Fig. 2.

5. αβ STRUCTURES • Periodicity less than 29nm induces site-bridging.

• In order to minimize site bridging α and β binding sites were alternated to create 2x and

4x designs with 18 αβ binding sites separated by 14nm each.

• AFM images show AuNP attachment onto DNA origami nanotubes in high yield (Fig. 4).

2x 18site αβ 4x 18site αβ

Figure 4: AFM images of 2x and 4x 18 binding site AB structures.

6. HETEROGENEOUS STRUCTURES • AuNP/QD heterogeneous structure were designed and synthesized with four 4x single

stranded DNA binding sites and one 2x biotin binding site with 14 nm periodicity.

• AFM and TEM analysis of the heterogeneous structure are shown in Fig. 5, while high

resolution TEM analysis, including EDS, of the nanoparticles is shown in Fig. 6.

Figure 5: AFM (left) image of the AuNP/QD heterogeneous structure shows successful attachment of

nanoparticles to the origami nanotube. TEM image (right) indicates the formation of heterostructures.

0nm

12nm

Figure 6: TEM analysis of free AuNPs and QDs. Low (a), medium (b), and high (d) resolution TEM

images of of mixture of AuNPs and QDs. EDS spectrum from AuNP (c) and QDs (e), respectively.