%ADehankar, Abhilasha%ADehankar, Abhilasha [William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, Ohio 43210, USA]%APorter, Thomas%APorter, Thomas [William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, Ohio 43210, USA]%AJohnson, Joshua%AJohnson, Joshua [Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA]%ACastro, Carlos [Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210, USA]%ACastro, Carlos%AWinter, Jessica%AWinter, Jessica [William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, Ohio 43210, USA, Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA, Department of Biomedical Engineering, The Ohio State University, 151 W. Woodruff Ave., Columbus, Ohio 43210, USA]%BJournal Name: The Journal of Chemical Physics; Journal Volume: 151; Journal Issue: 14; Related Information: CHORUS Timestamp: 2023-08-08 02:03:46 %D2019%IAmerican Institute of Physics %JJournal Name: The Journal of Chemical Physics; Journal Volume: 151; Journal Issue: 14; Related Information: CHORUS Timestamp: 2023-08-08 02:03:46 %K %MOSTI ID: 10120949 %PMedium: X %TCompact quantum dot surface modification to enable emergent behaviors in quantum dot-DNA composites %X

Quantum dot (QD) biological imaging and sensing applications often require surface modification with single-stranded deoxyribonucleic acid (ssDNA) oligonucleotides. Furthermore, ssDNA conjugation can be leveraged for precision QD templating via higher-order DNA nanostructures to exploit emergent behaviors in photonic applications. Use of ssDNA-QDs across these platforms requires compact, controlled conjugation that engenders QD stability over a wide pH range and in solutions of high ionic strength. However, current ssDNA-QD conjugation approaches suffer from limitations, such as the requirement for thick coatings, low control over ssDNA labeling density, requirement of large amounts of ssDNA, or low colloidal or photostability, restraining implementation in many applications. Here, we combine thin, multidentate, phytochelatin-3 (PC3) QD passivation techniques with strain-promoted copper-free alkyne-azide click chemistry to yield functional ssDNA-QDs with high stability. This process was broadly applicable across QD sizes (i.e., λem = 540, 560, 600 nm), ssDNA lengths (i.e., 10–16 base pairs, bps), and sequences (poly thymine, mixed bps). The resulting compact ssDNA-QDs displayed a fluorescence quenching efficiency of up to 89% by hybridization with complementary ssDNA-AuNPs. Furthermore, ssDNA-QDs were successfully incorporated with higher-order DNA origami nanostructure templates. Thus, this approach, combining PC3 passivation with click chemistry, generates ssDNA-PC3-QDs that enable emergent QD properties in DNA-based devices and applications.

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