High magnetic relaxivity in a fluorescent CdSe/CdS/ZnS quantum dot functionalized with MRI contrast molecules

McAdams, Simon G.; Lewis, David J.; McNaughter, Paul D.; Lewis, Edward A.; Haigh, Sarah J.; O’Brien, Paul; Tuna, Floriana

doi:10.1039/c7cc05537d

Cited by 17 publications

(8 citation statements)

References 41 publications

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“…42,43,49 The association of QDs and biomolecules by direct attachment to the nanocrystal surface has been widely used, for example with proteins, [50][51][52] carbodydrates, 25,53 polymers 54 and viruses. 55 In search of more efficient bimodal contrast agents for optical and magnetic resonance imaging (MRI), McAdams et al 37 anchored Gd III complexes on the QDs surface. The diethylenetriaminepentaacetic (DTPA) dianhydride was reacted with 4-aminothiophenol, followed by complexation with Gd III , yielding the thiol-functionalized DTPA-Gd III chelates.…”

Section: Direct Attachment To the Surfacementioning

confidence: 99%

“…[33][34][35] Also, more recently, QDs have been associated with paramagnetic compounds to develop multimodal nanoprobes for optical and magnetic resonance imaging. [36][37][38] Furthermore, QDs were also applied as photosensitizers in photodynamic therapy. 39,40 To be successful in all of these applications it is fundamental to prepare an efficient and stable bioconjugated system.…”

Section: Introductionmentioning

confidence: 99%

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(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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Quantum dots (QDs) are semiconductor nanocrystals, which present unique photophysical properties, enabling their application as new fluorescent platforms for biomedical sciences. Colloidal QDs are end-capped with organic or inorganic compounds, not only to prevent their agglomeration but also to provide reaction sites for the attachment of targeting (bio)molecules, nanoparticles or other interfaces, for specific biological purposes. The (bio)conjugation can involve non-covalent or covalent interactions, which can be accomplished through different strategies. The final assembly needs to maintain its chemical and optical stability and biochemical functionality. Although a relative good comprehension of the experimental procedures has been established, the bioconjugation process is still a challenge. The present manuscript aims to review the main (bio)conjugation strategies successfully applied to QDs, describing the steps necessary to prepare stable targeting fluorescent nanoplatforms, as well as some usual methods used to evaluate and optimize this process.

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Section: Direct Attachment To the Surfacementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

Pereira¹,

Monteiro²,

Albuquerque³

et al. 2019

J. Braz. Chem. Soc.

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“…Among many cadmium chalcogenide semiconductors, CdSe quantum dots have been widely studied in the literature [38][39][40][41][42]. Cadmium chalcogenides are well-known for their synthesis, yields, reliability, and stability.…”

Section: Introductionmentioning

confidence: 99%

3-Mercaptopropionic, 4-Mercaptobenzoic, and Oleic Acid-Capped CdSe Quantum Dots: Interparticle Distance, Anchoring Groups, and Surface Passivation

Santos

Baum

Kohlrausch

et al. 2019

Journal of Nanomaterials

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The optoelectronic properties of quantum dots are strongly controlled by the chemical nature of their surface-passivating ligands. In this work, we present the synthesis, characterization, and surface modification of CdSe quantum dots (QDs) and their application in solar cells. CdSe QDs were capped in oleic acid (OA), 3-mercaptopropionic acid (MPA), and 4-mercaptobenzoic acid (MBA). The QDs were characterized by transmission electron microscopy (TEM), UV-Vis absorption and emission spectrophotometry, thermogravimetric analyses, and 1H and 13C NMR. From TEM analysis, it has been observed that interparticle distance can be effectively controlled by the presence of different molecular size ligands. From the 1H and 13C NMR, specific types of interactions between the Cd2+ and the ligands have been observed. Although CdSe/OA presented larger interparticle distance as compared to CdSe/MPA and CdSe/MBA, the photocatalytic oxidation of the thiol groups on the surface of the MPA- and MBA-based quantum dots resulted in poor surface stabilization, ultimately resulting in poor power conversion efficiencies which were ca. 70% smaller than that of OA-based solar cell.

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“…Recently, McAdams and colleagues (2017) obtained a system with the highest relaxivity of 6800 mM −1 ·s −1 per nanoparticle (42.5 MHz, 27 °C) due to the bidentate attachment of ca . 620 magnetic centers, Gd(III) complexes of a DTPA-bisamide of p -aminothiophenol, per multishell CdSe/CdS/ZnS QD, although with a relatively low r 1 relaxivity per Gd(III) ( r 1 = 11 mM −1 ·s −1 ) 25 . Furthermore, the nanoprobe presented drastic quenching of the emission intensity, different from our bimodal nanosystems that remained highly fluorescent.…”

Section: Resultsmentioning

confidence: 99%

Hydrophilic Quantum Dots Functionalized with Gd(III)-DO3A Monoamide Chelates as Bright and Effective T1-weighted Bimodal Nanoprobes

Pereira

Monteiro

et al. 2019

Sci Rep

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Magnetic resonance imaging (MRI) is a powerful non-invasive diagnostic tool that enables distinguishing healthy from pathological tissues, with high anatomical detail. Nevertheless, MRI is quite limited in the investigation of molecular/cellular biochemical events, which can be reached by fluorescence-based techniques. Thus, we developed bimodal nanosystems consisting in hydrophilic quantum dots (QDs) directly conjugated to Gd(III)-DO3A monoamide chelates, a Gd(III)-DOTA derivative, allowing for the combination of the advantages of both MRI and fluorescence-based tools. These nanoparticulate systems can also improve MRI contrast, by increasing the local concentration of paramagnetic chelates. Transmetallation assays, optical characterization, and relaxometric analyses, showed that the developed bimodal nanoprobes have great chemical stability, bright fluorescence, and high relaxivities. Moreover, fluorescence correlation spectroscopy (FCS) analysis allowed us to distinguish nanosystems containing different amounts of chelates/QD. Also, inductively coupled plasma optical emission spectrometry (ICP – OES) indicated a conjugation yield higher than 75%. Our nanosystems showed effective longitudinal relaxivities per QD and per paramagnetic ion, at least 5 times [per Gd(III)] and 100 times (per QD) higher than the r1 for Gd(III)-DOTA chelates, suitable for T1-weighted imaging. Additionally, the bimodal nanoparticles presented negligible cytotoxicity, and efficiently labeled HeLa cells as shown by fluorescence. Thus, the developed nanosystems show potential as strategic probes for fluorescence analyses and MRI, being useful for investigating a variety of biological processes.

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High magnetic relaxivity in a fluorescent CdSe/CdS/ZnS quantum dot functionalized with MRI contrast molecules

Cited by 17 publications

References 41 publications

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

(Bio)conjugation Strategies Applied to Fluorescent Semiconductor Quantum Dots

3-Mercaptopropionic, 4-Mercaptobenzoic, and Oleic Acid-Capped CdSe Quantum Dots: Interparticle Distance, Anchoring Groups, and Surface Passivation

Hydrophilic Quantum Dots Functionalized with Gd(III)-DO3A Monoamide Chelates as Bright and Effective T1-weighted Bimodal Nanoprobes

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