1
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Sadeghi E, Mastracco P, Gonzàlez-Rosell A, Copp SM, Bogdanov P. Multi-Objective Design of DNA-Stabilized Nanoclusters Using Variational Autoencoders With Automatic Feature Extraction. ACS NANO 2024; 18:26997-27008. [PMID: 39288200 PMCID: PMC11447918 DOI: 10.1021/acsnano.4c09640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Revised: 08/30/2024] [Accepted: 09/06/2024] [Indexed: 09/19/2024]
Abstract
DNA-stabilized silver nanoclusters (AgN-DNAs) have sequence-tuned compositions and fluorescence colors. High-throughput experiments together with supervised machine learning models have recently enabled design of DNA templates that select for AgN-DNA properties, including near-infrared (NIR) emission that holds promise for deep tissue bioimaging. However, these existing models do not enable simultaneous selection of multiple AgN-DNA properties, and require significant expert input for feature engineering and class definitions. This work presents a model for multiobjective, continuous-property design of AgN-DNAs with automatic feature extraction, based on variational autoencoders (VAEs). This model is generative, i.e., it learns both the forward mapping from DNA sequence to AgN-DNA properties and the inverse mapping from properties to sequence, and is trained on an experimental data set of DNA sequences paired with AgN-DNA fluorescence properties. Experimental testing shows that the model enables effective design of AgN-DNA emission, including bright NIR AgN-DNAs with 4-fold greater abundance compared to training data. In addition, Shapley analysis is employed to discern learned nucleobase patterns that correspond to fluorescence color and brightness. This generative model can be adapted for a range of biomolecular systems with sequence-dependent properties, enabling precise design of emerging biomolecular nanomaterials.
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Affiliation(s)
- Elham Sadeghi
- Department
of Computer Science, University at Albany-SUNY, Albany, New York 12222, United States
| | - Peter Mastracco
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Anna Gonzàlez-Rosell
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Stacy M. Copp
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
- Department
of Chemistry, University of California, Irvine, California 92697, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of
California, Irvine, California 92697, United States
| | - Petko Bogdanov
- Department
of Computer Science, University at Albany-SUNY, Albany, New York 12222, United States
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2
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Rajeev A, Bhatia D. DNA-templated fluorescent metal nanoclusters and their illuminating applications. NANOSCALE 2024. [PMID: 39292491 DOI: 10.1039/d4nr03429e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
After the discovery of DNA during the mid-20th century, a multitude of novel methodologies have surfaced which exploit DNA for its various properties. One such recently developed application of DNA is as a template in metal nanocluster formation. In the early years of the new millennium, a group of researchers found that DNA can be adopted as a template for the binding of metal nanoparticles that ultimately form nanoclusters. Three metal nanoclusters have been studied so far, including silver, gold, and copper, which have a plethora of biological applications. This review focuses on the synthesis, mechanisms, and novel applications of DNA-templated metal nanoclusters, including the therapies that have employed them for their wide range of fluorescent properties, and the future perspectives related to their development by exploiting machine learning algorithms and molecular dynamics simulation studies.
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Affiliation(s)
- Ashwin Rajeev
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat-382355, India.
| | - Dhiraj Bhatia
- Department of Biological Sciences and Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, Gujarat-382355, India.
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3
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Gonzàlez-Rosell A, Copp SM. An Atom-Precise Understanding of DNA-Stabilized Silver Nanoclusters. Acc Chem Res 2024; 57:2117-2129. [PMID: 38995323 PMCID: PMC11308368 DOI: 10.1021/acs.accounts.4c00256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/28/2024] [Accepted: 06/28/2024] [Indexed: 07/13/2024]
Abstract
ConspectusDNA-stabilized silver nanoclusters (AgN-DNAs) are sequence-encoded fluorophores. Like other noble metal nanoclusters, the optical properties of AgN-DNAs are dictated by their atomically precise sizes and shapes. What makes AgN-DNAs unique is that nanocluster size and shape are controlled by nucleobase sequence of the templating DNA oligomer. By choice of DNA sequence, it is possible to synthesize a wide range of AgN-DNAs with diverse emission colors and other intriguing photophysical properties. AgN-DNAs hold significant potential as "programmable" emitters for biological imaging due to their combination of small molecular-like sizes, bright and sequence-tuned fluorescence, low toxicities, and cost-effective synthesis. In particular, the potential to extend AgN-DNAs into the second near-infrared region (NIR-II) is promising for deep tissue imaging, which is a major area of interest for advancing biomedical imaging. Achieving this goal requires a deep understanding of the structure-property relationships that govern AgN-DNAs in order to design AgN-DNA emitters with sizes and geometries that support NIR-II emission.In recent years, major advances have been made in understanding the structure and composition of AgN-DNAs, enabling new insights into the correlation of nanocluster structure and photophysical properties. These advances have hinged on combined innovations in mass characterization and crystallography of compositionally pure AgN-DNAs, together with combinatorial experiments and machine learning-guided design. A combined approach is essential due to the major challenge of growing suitable AgN-DNA crystals for diffraction and to the labor-intensive nature of preparing and solving the molecular formulas of atomically precise AgN-DNAs by mass spectrometry. These approaches alone are not feasibly scaled to explore the large sequence space of DNA oligomer templates for AgN-DNAs.This account describes recent fundamental advances in AgN-DNA science that have been enabled by high throughput synthesis and fluorimetry together with detailed analytical studies of purified AgN-DNAs. First, short introductions to nanocluster chemistry and AgN-DNA basics are presented. Then, we review recent large-scale studies that have screened thousands of DNA templates for AgN-DNAs, leading to discovery of distinct classes of these emitters with unique cluster core compositions and ligand chemistries. In particular, the discovery of a new class of chloride-stabilized AgN-DNAs enabled the first ab initio calculations of AgN-DNA electronic structure and present new approaches to stabilize these emitters in biologically relevant conditions. Near-infrared (NIR) emissive AgN-DNAs are also found to exhibit diverse structures and properties. Finally, we conclude by highlighting recent proof-of-principle demonstrations of NIR AgN-DNAs for targeted fluorescence imaging. Continued efforts may future push AgN-DNAs into the tissue transparency window for fluorescence imaging in the NIR-II tissue transparency window.
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Affiliation(s)
- Anna Gonzàlez-Rosell
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Stacy M. Copp
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of
California, Irvine, California 92697, United States
- Department
of Chemistry, University of California, Irvine, California 92697, United States
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4
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Liisberg MB, Vosch T. Fluorescence Screening of DNA-AgNCs with Pulsed White Light Excitation. NANO LETTERS 2024; 24:7987-7991. [PMID: 38905483 PMCID: PMC11229690 DOI: 10.1021/acs.nanolett.4c01561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/23/2024]
Abstract
DNA-stabilized silver nanoclusters (DNA-AgNCs) are a class of fluorophores with interesting photophysical properties dominated by the choice of DNA sequence. Screening methods with ultraviolet excitation and steady state well plate readers have previously been used for deepening the understanding between DNA sequence and emission color of the resulting DNA-AgNCs. Here, we present a new method for screening DNA-AgNCs by using pulsed white light excitation (λex ≈ 490-900 nm). By subtraction and time gating we are able to circumvent the dominating scatter of the white excitation light and extract both temporally and spectrally resolved emission of DNA-AgNCs over the visible to near-infrared range. Additionally, we are able to identify weak long-lived emission, which is often buried underneath the intense nanosecond fluorescence. This new approach will be useful for future screening of DNA-AgNCs (or other novel emissive materials) and aid machine-learning models by providing a richer training data set.
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Affiliation(s)
- Mikkel Baldtzer Liisberg
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Tom Vosch
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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5
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Liasi Z, Jensen L, Mikkelsen KV. A Combined Quantum Mechanics and Molecular Mechanics Approach for Simulating the Optical Properties of DNA-Stabilized Silver Nanoclusters. J Chem Theory Comput 2024; 20:937-945. [PMID: 38164716 DOI: 10.1021/acs.jctc.3c01022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
DNA-stabilized silver nanoclusters have emerged as an intriguing type of nanomaterial due to their unique optical and electronic properties, with potential applications in areas such as biosensing and imaging. The development of efficient methods for modeling these properties is paramount for furthering the understanding and utilization of these clusters. In this study, a hybrid quantum mechanical and molecular mechanical approach for modeling the optical properties of a DNA-templated silver nanocluster is evaluated. The influence of different parameters, including ligand fragmentation, damping, embedding potential, basis set, and density functional, is investigated. The results demonstrate that the most important parameter is the type of atomic properties used to represent the ligands, with isotropic dipole-dipole polarizabilities outperforming the rest. This underscores the importance of an appropriate representation of the ligands, particularly through the selection of the properties used to represent them. Moreover, the results are compared to experimental data, showing that the applied methodology is reliable and effective for the modeling of DNA-stabilized silver nanoclusters. These findings offer valuable insights that may guide future computational efforts to explore and harness the potential of these novel systems.
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Affiliation(s)
- Zacharias Liasi
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
| | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kurt V Mikkelsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø 2100, Denmark
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6
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Guha R, Gonzàlez-Rosell A, Rafik M, Arevalos N, Katz BB, Copp SM. Electron count and ligand composition influence the optical and chiroptical signatures of far-red and NIR-emissive DNA-stabilized silver nanoclusters. Chem Sci 2023; 14:11340-11350. [PMID: 37886084 PMCID: PMC10599602 DOI: 10.1039/d3sc02931j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/09/2023] [Indexed: 10/28/2023] Open
Abstract
Near-infrared (NIR) emissive DNA-stabilized silver nanoclusters (AgN-DNAs) are promising fluorophores in the biological tissue transparency windows. Hundreds of NIR-emissive AgN-DNAs have recently been discovered, but their structure-property relationships remain poorly understood. Here, we investigate 19 different far-red and NIR emissive AgN-DNA species stabilized by 10-base DNA templates, including well-studied emitters whose compositions and chiroptical properties have never been reported before. The molecular formula of each purified species is determined by high-resolution mass spectrometry and correlated to its optical absorbance, emission, and circular dichroism (CD) spectra. We find that there are four distinct compositions for AgN-DNAs emissive at the far red/NIR spectral border. These emitters are either 8-electron clusters stabilized by two DNA oligomer copies or 6-electron clusters with one of three different ligand compositions: two oligomer copies, three oligomer copies, or two oligomer copies with additional chlorido ligands. Distinct optical and chiroptical signatures of 6-electron AgN-DNAs correlate with each ligand composition. AgN-DNAs with three oligomer ligands exhibit shorter Stokes shifts than AgN-DNAs with two oligomers, and AgN-DNAs with chlorido ligands have increased Stokes shifts and significantly suppressed visible CD transitions. Nanocluster electron count also significantly influences electronic structure and optical properties, with 6-electron and 8-electron AgN-DNAs exhibiting distinct absorbance and CD spectral features. This study shows that the optical and chiroptical properties of NIR-emissive AgN-DNAs are highly sensitive to nanocluster composition and illustrates the diversity of structure-property relationships for NIR-emissive AgN-DNAs, which could be harnessed to precisely tune these emitters for bioimaging applications.
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Affiliation(s)
- Rweetuparna Guha
- Department of Materials Science and Engineering, University of California Irvine CA 92697 USA
| | - Anna Gonzàlez-Rosell
- Department of Materials Science and Engineering, University of California Irvine CA 92697 USA
| | - Malak Rafik
- Department of Materials Science and Engineering, University of California Irvine CA 92697 USA
| | - Nery Arevalos
- Department of Materials Science and Engineering, University of California Irvine CA 92697 USA
| | - Benjamin B Katz
- Department of Chemistry, University of California Irvine CA 92697 USA
| | - Stacy M Copp
- Department of Materials Science and Engineering, University of California Irvine CA 92697 USA
- Department of Physics and Astronomy, University of California Irvine CA 92697 USA
- Department of Chemical and Biomolecular Engineering, University of California Irvine CA 92697 USA
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7
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Guha R, Rafik M, Gonzàlez-Rosell A, Copp SM. Heat, pH, and salt: synthesis strategies to favor formation of near-infrared emissive DNA-stabilized silver nanoclusters. Chem Commun (Camb) 2023; 59:10488-10491. [PMID: 37551832 DOI: 10.1039/d3cc02896h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
We present chemical synthesis strategies for DNA-stabilized silver nanoclusters (AgN-DNAs) with near-infrared (NIR) emission in the biological tissue transparency windows. Elevated temperatures can significantly increase chemical yield of near-infrared nanoclusters. In most cases, basic pH favors near-infrared nanoclusters while micromolar amounts of NaCl inhibit their formation.
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Affiliation(s)
- Rweetuparna Guha
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA.
| | - Malak Rafik
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA.
| | - Anna Gonzàlez-Rosell
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA.
| | - Stacy M Copp
- Department of Materials Science and Engineering, University of California, Irvine, CA 92697, USA.
- Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, CA 92697, USA
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8
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Liasi Z, Hillers-Bendtsen AE, Jensen L, Mikkelsen KV. Elucidating the Mystery of DNA-Templating Effects on a Silver Nanocluster. J Phys Chem Lett 2023:5727-5733. [PMID: 37318362 DOI: 10.1021/acs.jpclett.3c00977] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
This presentation considers the effects that DNA-templating has on the optical properties of a 16-atom silver cluster. To accomplish this, hybrid quantum mechanical and molecular mechanical simulations of a Ag16-DNA complex have been carried out and compared with pure time-dependent density functional theory calculations of two Ag16 clusters in vacuum. The presented results show that the templating DNA polymers both red-shift the one-photon absorption of the silver cluster and increase its intensity. This occurs through a change in cluster shape prompted by the structural constraints of the DNA ligands combined with silver-DNA interactions. The overall charge of the cluster also contributes to the observed optical response, as oxidation of the cluster results in a simultaneous blue-shift of the one-photon absorption and a decrease in intensity. Additionally, the changes in shape and environment also lead to a blue-shift and enhancement of the two-photon absorption.
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Affiliation(s)
- Zacharias Liasi
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | | | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Kurt V Mikkelsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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9
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Lewis D, Setzler C, Goodwin PM, Thomas K, Branham M, Arrington CA, Petty JT. Interrupted DNA and Slow Silver Cluster Luminescence. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:10574-10584. [PMID: 37313118 PMCID: PMC10258842 DOI: 10.1021/acs.jpcc.3c01050] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/16/2023] [Indexed: 06/15/2023]
Abstract
A DNA-silver cluster conjugate is a hierarchical chromophore with a partly reduced silver core embedded within the DNA nucleobases that are covalently linked by the phosphodiester backbone. Specific sites within a polymeric DNA can be targeted to spectrally tune the silver cluster. Here, the repeated (C2A)6 strand is interrupted with a thymine, and the resulting (C2A)2-T-(C2A)4 forms only Ag106+, a chromophore with both prompt (∼1 ns) green and sustained (∼102 μs) red luminescence. Thymine is an inert placeholder that can be removed, and the two fragments (C2A)2 and (C2A)4 also produce the same Ag106+ adduct. In relation to (C2A)2T(C2A)4, the (C2A)2 + (C2A)4 pair is distinguished because the red Ag106+ luminescence is ∼6× lower, relaxes ∼30% faster, and is quenched ∼2× faster with O2. These differences suggest that a specific break in the phosphodiester backbone can regulate how a contiguous vs broken scaffold wraps and better protects its cluster adduct.
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Affiliation(s)
- David Lewis
- Department
of Chemistry, Furman University, Greenville, South Carolina 29163, United States
| | - Caleb Setzler
- Department
of Chemistry, Furman University, Greenville, South Carolina 29163, United States
| | - Peter M. Goodwin
- Center
for Integrated Nanotechnologies, Mail Stop K771, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Kirsten Thomas
- Department
of Chemistry, Furman University, Greenville, South Carolina 29163, United States
| | - Makayla Branham
- Department
of Chemistry, Furman University, Greenville, South Carolina 29163, United States
| | - Caleb A. Arrington
- Department
of Chemistry, Wofford College, Spartanburg, South Carolina 29303, United States
| | - Jeffrey T. Petty
- Department
of Chemistry, Furman University, Greenville, South Carolina 29163, United States
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10
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Gonzàlez-Rosell A, Malola S, Guha R, Arevalos NR, Matus MF, Goulet ME, Haapaniemi E, Katz BB, Vosch T, Kondo J, Häkkinen H, Copp SM. Chloride Ligands on DNA-Stabilized Silver Nanoclusters. J Am Chem Soc 2023; 145:10721-10729. [PMID: 37155337 DOI: 10.1021/jacs.3c01366] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
DNA-stabilized silver nanoclusters (AgN-DNAs) are known to have one or two DNA oligomer ligands per nanocluster. Here, we present the first evidence that AgN-DNA species can possess additional chloride ligands that lead to increased stability in biologically relevant concentrations of chloride. Mass spectrometry of five chromatographically isolated near-infrared (NIR)-emissive AgN-DNA species with previously reported X-ray crystal structures determines their molecular formulas to be (DNA)2[Ag16Cl2]8+. Chloride ligands can be exchanged for bromides, which red-shift the optical spectra of these emitters. Density functional theory (DFT) calculations of the 6-electron nanocluster show that the two newly identified chloride ligands were previously assigned as low-occupancy silvers by X-ray crystallography. DFT also confirms the stability of chloride in the crystallographic structure, yields qualitative agreement between computed and measured UV-vis absorption spectra, and provides interpretation of the 35Cl-nuclear magnetic resonance spectrum of (DNA)2[Ag16Cl2]8+. A reanalysis of the X-ray crystal structure confirms that the two previously assigned low-occupancy silvers are, in fact, chlorides, yielding (DNA)2[Ag16Cl2]8+. Using the unusual stability of (DNA)2[Ag16Cl2]8+ in biologically relevant saline solutions as a possible indicator of other chloride-containing AgN-DNAs, we identified an additional AgN-DNA with a chloride ligand by high-throughput screening. Inclusion of chlorides on AgN-DNAs presents a promising new route to expand the diversity of AgN-DNA structure-property relationships and to imbue these emitters with favorable stability for biophotonics applications.
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Affiliation(s)
- Anna Gonzàlez-Rosell
- Department of Materials Science and Engineering, University of California, Irvine, California 92697, United States
| | - Sami Malola
- Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Rweetuparna Guha
- Department of Materials Science and Engineering, University of California, Irvine, California 92697, United States
| | - Nery R Arevalos
- Department of Materials Science and Engineering, University of California, Irvine, California 92697, United States
| | - María Francisca Matus
- Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Meghen E Goulet
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Esa Haapaniemi
- Department of Chemistry, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Benjamin B Katz
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Tom Vosch
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark
| | - Jiro Kondo
- Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Hannu Häkkinen
- Departments of Chemistry and Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Stacy M Copp
- Department of Materials Science and Engineering, University of California, Irvine, California 92697, United States
- Department of Physics and Astronomy, University of California, Irvine, California 92697, United States
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, United States
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11
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David F, Setzler C, Sorescu A, Lieberman RL, Meilleur F, Petty JT. Mapping H + in the Nanoscale (A 2C 4) 2-Ag 8 Fluorophore. J Phys Chem Lett 2022; 13:11317-11322. [PMID: 36453924 DOI: 10.1021/acs.jpclett.2c03161] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
When strands of DNA encapsulate silver clusters, supramolecular optical chromophores develop. However, how a particular structure endows a specific spectrum remains poorly understood. Here, we used neutron diffraction to map protonation in (A2C4)2-Ag8, a green-emitting fluorophore with a "Big Dipper" arrangement of silvers. The DNA host has two substructures with distinct protonation patterns. Three cytosines from each strand collectively chelate handle-like array of three silvers, and calorimetry studies suggest Ag+ cross-links. The twisted cytosines are further joined by hydrogen bonds from fully protonated amines. The adenines and their neighboring cytosine from each strand anchor a dipper-like group of five silvers via their deprotonated endo- and exocyclic nitrogens. Typically, exocyclic amines are strongly basic, so their acidification and deprotonation in (A2C4)2-Ag8 suggest that silvers perturb the electron distribution in the aromatic nucleobases. The different protonation states in (A2C4)2-Ag8 suggest that atomic level structures can pinpoint how to control and tune the electronic spectra of these nanoscale chromophores.
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Affiliation(s)
- Fred David
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - Caleb Setzler
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - Alexandra Sorescu
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Flora Meilleur
- Department of Molecular and Structural Biochemistry, North Carolina State University, Campus Box 7622, Raleigh, North Carolina 27695, United States
- Neutron Scattering Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831, United States
| | - Jeffrey T Petty
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
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12
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Mastracco P, Gonzàlez-Rosell A, Evans J, Bogdanov P, Copp SM. Chemistry-Informed Machine Learning Enables Discovery of DNA-Stabilized Silver Nanoclusters with Near-Infrared Fluorescence. ACS NANO 2022; 16:16322-16331. [PMID: 36124941 PMCID: PMC9620400 DOI: 10.1021/acsnano.2c05390] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
DNA can stabilize silver nanoclusters (AgN-DNAs) whose atomic sizes and diverse fluorescence colors are selected by nucleobase sequence. These programmable nanoclusters hold promise for sensing, bioimaging, and nanophononics. However, DNA's vast sequence space challenges the design and discovery of AgN-DNAs with tailored properties. In particular, AgN-DNAs with bright near-infrared luminescence above 800 nm remain rare, placing limits on their applications for bioimaging in the tissue transparency windows. Here, we present a design method for near-infrared emissive AgN-DNAs. By combining high-throughput experimentation and machine learning with fundamental information from AgN-DNA crystal structures, we distill the salient DNA sequence features that determine AgN-DNA color, for the entire known spectral range of these nanoclusters. A succinct set of nucleobase staple features are predictive of AgN-DNA color. By representing DNA sequences in terms of these motifs, our machine learning models increase the design success for near-infrared emissive AgN-DNAs by 12.3 times as compared to training data, nearly doubling the number of known AgN-DNAs with bright near-infrared luminescence above 800 nm. These results demonstrate how incorporating known structure-property relationships into machine learning models can enhance materials study and design, even for sparse and imbalanced training data.
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Affiliation(s)
- Peter Mastracco
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Anna Gonzàlez-Rosell
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
| | - Joshua Evans
- Chaffey
Community College, Rancho
Cucamonga, California 91737, United States
| | - Petko Bogdanov
- Department
of Computer Science, University at Albany-SUNY, Albany, New York 12222, United States
| | - Stacy M. Copp
- Department
of Materials Science and Engineering, University
of California, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of
California, Irvine, California 92697, United States
- Department
of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697, United States
- Email
for S.M.C.:
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13
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Ramasanoff RR, Sokolov PA. Intersystem Crossing Rates of Violet-, Green- and Red-emitting DNA Stabilized Silver Luminescent Clusters. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.140081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Cerretani C, Liisberg MB, Rück V, Kondo J, Vosch T. The effect of inosine on the spectroscopic properties and crystal structure of a NIR-emitting DNA-stabilized silver nanocluster. NANOSCALE ADVANCES 2022; 4:3212-3217. [PMID: 36132821 PMCID: PMC9416947 DOI: 10.1039/d2na00325b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 06/18/2022] [Indexed: 05/16/2023]
Abstract
The effect of replacing guanosines with inosines in the two stabilizing strands (5'-CACCTAGCGA-3') of the NIR emissive DNA-Ag16NC was investigated. The spectroscopic behavior of the inosine mutants is position-dependent: when the guanosine in position 7 was exchanged, the nanosecond fluorescence decay time shortened, while having the inosine in position 9 made the decay time longer. Thanks to structural information gained from single crystal X-ray diffraction measurements, it was possible to propose a mechanistic origin for the observed changes.
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Affiliation(s)
- Cecilia Cerretani
- Nanoscience Center and Department of Chemistry, University of Copenhagen Universitetsparken 5 2100 Copenhagen Denmark
| | - Mikkel B Liisberg
- Nanoscience Center and Department of Chemistry, University of Copenhagen Universitetsparken 5 2100 Copenhagen Denmark
| | - Vanessa Rück
- Nanoscience Center and Department of Chemistry, University of Copenhagen Universitetsparken 5 2100 Copenhagen Denmark
| | - Jiro Kondo
- Department of Materials and Life Sciences, Sophia University 7-1 Kioi-cho Chiyoda-ku 102-8554 Tokyo Japan
| | - Tom Vosch
- Nanoscience Center and Department of Chemistry, University of Copenhagen Universitetsparken 5 2100 Copenhagen Denmark
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15
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Petty JT, Lewis D, Carnahan S, Kim D, Couch C. Tug-of-War between DNA Chelation and Silver Agglomeration in DNA-Silver Cluster Chromophores. J Phys Chem B 2022; 126:3822-3830. [PMID: 35594191 DOI: 10.1021/acs.jpcb.2c01054] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Supramolecular chromophores form when a DNA traps silvers that then coalesce into clusters with discrete, molecular electronic states. However, DNA strands are polymeric ligands that disperse silvers and thus curb agglomeration. We study this competition using two chromophores that share three common components: a dimeric DNA scaffold, Ag+-nucleobase base pairs, and Ag0 chromophores. The DNA host C4-A2-iC4T mimics structural elements in a DNA-cluster crystal structure using a phosphodiester backbone with combined 5' → 3' and 3' → 5' (indicated by "i") directions. The backbone directions must alternate to form the two silver clusters, and this interdependence supports a silver-linked structure. This template creates two chromophores with distinct sizes, charges, and hence spectra: (C4-A2-iC4T)2/Ag117+ with λabs/λem = 430/520 nm and (C4-A2-iC4T)2/Ag148+ with λabs/λem = 510/630 nm. The Ag+ and Ag0 constituents in these partially oxidized clusters are linked with structural elements in C4-A2-iC4T. Ag+ alone binds sparsely but strongly to form C4-A2-iC4T/3-4 Ag+ and (C4-A2-iC4T)2/7-8 Ag+ complexes, and these stoichiometries suggest that Ag+ cross-links pairs of cytosines to form a hairpin with a metallo-C4/iC4 duplex and an adenine loop. The Ag0 are chemically orthogonal because they can be oxidatively etched without disrupting the underlying Ag+-DNA matrix, and their reactivity is attributed to their valence electrons and weaker chelation by the adenines. These studies suggest that Ag+ disperses with the cytosines to create an adenine binding pocket for the Ag0 cluster chromophores.
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Affiliation(s)
- Jeffrey T Petty
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - David Lewis
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - Savannah Carnahan
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - Dahye Kim
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
| | - Caroline Couch
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, United States
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16
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Petty JT, Carnahan S, Kim D, Lewis D. Long-lived Ag 10 6+ luminescence and a split DNA scaffold. J Chem Phys 2021; 154:244302. [PMID: 34241360 DOI: 10.1063/5.0056214] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Molecular silver clusters emit across the visible to near-infrared, and specific chromophores can be formed using DNA strands. We study C4AC4TC3G that selectively coordinates and encapsulates Ag10 6+, and this chromophore has two distinct electronic transitions. The green emission is strong and prompt with ϕ = 18% and τ = 1.25 ns, and the near-infrared luminescence is weaker, slower with τ = 50 µs, and is partly quenched by oxygen, suggesting phosphorescence. This lifetime can be modulated by the DNA host, and we consider two derivatives of C4AC4TC3G with similar sequences but distinct structures. In one variant, thymine was excised to create an abasic gap in an otherwise intact strand. In the other, the covalent phosphate linkage was removed to split the DNA scaffold into two fragments. In relation to the contiguous strands, the broken template speeds the luminescence decay by twofold, and this difference may be due to greater DNA flexibility. These modifications suggest that a DNA can be structurally tuned to modulate metastable electronic states in its silver cluster adducts.
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Affiliation(s)
- Jeffrey T Petty
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA
| | - Savannah Carnahan
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA
| | - Dahye Kim
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA
| | - David Lewis
- Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA
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17
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Rück V, Cerretani C, Neacşu VA, Liisberg MB, Vosch T. Observation of microsecond luminescence while studying two DNA-stabilized silver nanoclusters emitting in the 800-900 nm range. Phys Chem Chem Phys 2021; 23:13483-13489. [PMID: 34109959 DOI: 10.1039/d1cp01731d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We investigated two DNA-stabilized silver nanoclusters (DNA-AgNCs) that show multiple absorption features in the visible region, and emit around 811 nm (DNA811-AgNC) and 841 nm (DNA841-AgNC). Both DNA-AgNCs have large Stokes shifts and can be efficiently excited with red light. A comparison with the commercially available Atto740 yielded fluorescence quantum yields in the same order of magnitude, but a higher photon output above 800 nm since both DNA-AgNCs are more red-shifted. The study of both DNA-AgNCs also revealed previously unobserved photophysical behavior for this class of emitters. The fluorescence quantum yield and decay time of DNA841-AgNC can be increased upon consecutive heating/cooling cycles. DNA811-AgNC has an additional absorption band around 470 nm, which is parallel in orientation to the lowest energy transition at 640 nm. Furthermore, we observed for the first time a DNA-AgNC population (as part of the DNA811-AgNC sample) with green and near-infrared emissive states with nanosecond and microsecond decay times, respectively. A similar dual emissive DNA-AgNC stabilized by a different 10-base DNA strand is also reported in the manuscript. These two examples highlight the need to investigate the presence of red-shifted microsecond emission for this class of emitters.
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Affiliation(s)
- Vanessa Rück
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark.
| | - Cecilia Cerretani
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark.
| | - Vlad A Neacşu
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark.
| | - Mikkel B Liisberg
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark.
| | - Tom Vosch
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen 2100, Denmark.
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18
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Gonzàlez-Rosell A, Cerretani C, Mastracco P, Vosch T, Copp SM. Structure and luminescence of DNA-templated silver clusters. NANOSCALE ADVANCES 2021; 3:1230-1260. [PMID: 36132866 PMCID: PMC9417461 DOI: 10.1039/d0na01005g] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/21/2021] [Indexed: 05/05/2023]
Abstract
DNA serves as a versatile template for few-atom silver clusters and their organized self-assembly. These clusters possess unique structural and photophysical properties that are programmed into the DNA template sequence, resulting in a rich palette of fluorophores which hold promise as chemical and biomolecular sensors, biolabels, and nanophotonic elements. Here, we review recent advances in the fundamental understanding of DNA-templated silver clusters (Ag N -DNAs), including the role played by the silver-mediated DNA complexes which are synthetic precursors to Ag N -DNAs, structure-property relations of Ag N -DNAs, and the excited state dynamics leading to fluorescence in these clusters. We also summarize the current understanding of how DNA sequence selects the properties of Ag N -DNAs and how sequence can be harnessed for informed design and for ordered multi-cluster assembly. To catalyze future research, we end with a discussion of several opportunities and challenges, both fundamental and applied, for the Ag N -DNA research community. A comprehensive fundamental understanding of this class of metal cluster fluorophores can provide the basis for rational design and for advancement of their applications in fluorescence-based sensing, biosciences, nanophotonics, and catalysis.
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Affiliation(s)
- Anna Gonzàlez-Rosell
- Department of Materials Science and Engineering, University of California Irvine California 92697-2585 USA
| | - Cecilia Cerretani
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5 2100 Copenhagen Denmark
| | - Peter Mastracco
- Department of Materials Science and Engineering, University of California Irvine California 92697-2585 USA
| | - Tom Vosch
- Nanoscience Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5 2100 Copenhagen Denmark
| | - Stacy M Copp
- Department of Materials Science and Engineering, University of California Irvine California 92697-2585 USA
- Department of Physics and Astronomy, University of California Irvine California 92697-4575 USA
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19
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Copp SM, Gonzàlez-Rosell A. Large-scale investigation of the effects of nucleobase sequence on fluorescence excitation and Stokes shifts of DNA-stabilized silver clusters. NANOSCALE 2021; 13:4602-4613. [PMID: 33605954 PMCID: PMC8043073 DOI: 10.1039/d0nr08300c] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
DNA-stabilized silver clusters (AgN-DNAs) exhibit diverse sequence-programmed fluorescence, making these tunable nanoclusters promising sensors and bioimaging probes. Recent advances in the understanding of AgN-DNA structures and optical properties have largely relied on detailed characterization of single species isolated by chromatography. Because most AgN-DNAs are unstable under chromatography, such studies do not fully capture the diversity of these clusters. As an alternative method, we use high-throughput synthesis and spectroscopy to measure steady state Stokes shifts of hundreds of AgN-DNAs. Steady state Stokes shift is of interest because its magnitude is determined by energy relaxation processes which may be sensitive to specific cluster geometry, attachment to the DNA template, and structural engagement of solvent molecules. We identify 305 AgN-DNA samples with single-peaked emission and excitation spectra, a characteristic of pure solutions and single emitters, which thus likely contain a dominant emissive AgN-DNA species. Steady state Stokes shifts of these samples vary widely, are in agreement with values reported for purified clusters, and are several times larger than for typical organic dyes. We then examine how DNA sequence selects AgN-DNA excitation energies and Stokes shifts, comment on possible mechanisms for energy relaxation processes in AgN-DNAs, and discuss how differences in AgN-DNA structure and DNA conformation may result in the wide distribution of optical properties observed here. These results may aid computational studies seeking to understand the fluorescence process in AgN-DNAs and the relations of this process to AgN-DNA structure.
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Affiliation(s)
- Stacy M Copp
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA 92697-2585, USA. and Department of Physics and Astronomy, University of California, Irvine, Irvine, CA 92697-4575, USA and Department of Chemical and Biomolecular Engineering, University of California, Irvine, Irvine, CA 92697-2580, USA
| | - Anna Gonzàlez-Rosell
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA 92697-2585, USA.
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