Peptide-Labeled Near-Infrared Quantum Dots for Imaging Tumor Vasculature in Living Subjects

Cai, Weibo; Shin, Dongwoon; Chen, Kai; Gheysens, Olivier; Cao, Qizhen; Wang, Shan X.; Gambhir, Sanjiv S.; Chen, Xiaoyuan

doi:10.1021/nl052405t

Cited by 889 publications

(810 citation statements)

References 37 publications

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“…Due to their super brightness and photostability, quantum dots have sparkled tremendous interests in the biological sciences community and have rapidly found its way into many applications including in vivo animal imaging [17,18]. Even with their superior optical properties of QDs, the same challenges remain for optical imaging at non-superficial tissue sites, which are the presence of strong background autofluorescence and photon absorbance/ scattering by living tissue.…”

Section: Discussionmentioning

confidence: 99%

Improved QD-BRET conjugates for detection and imaging

Xing

Koh

et al. 2008

Biochemical and Biophysical Research Communications

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Self-illuminating quantum dots, also known as QD-BRET conjugates, are a new class of quantum dots bioconjugates which do not need external light for excitation. Instead, light emission relies on the bioluminescence resonance energy transfer from the attached Renilla luciferase enzyme, which emits light upon the oxidation of its substrate. QD-BRET combines the advantages of the QDs (such as superior brightness & photostability, tunable emission, multiplexing) as well as the high sensitivity of bioluminescence imaging, thus holds the promise for improved deep tissue in vivo imaging. Although studies have demonstrated the superior sensitivity and deep tissue imaging potential, the stability of the QD-BRET conjugates in biological environment needs to be improved for long-term imaging studies such as in vivo cell trafficking. In this study, we seek to improve the stability of QD-BRET probes through polymeric encapsulation with a polyacrylamide gel. Results show that encapsulation caused some activity loss, but significantly improved both the in vitro serum stability and in vivo stability when subcutaneously injected into the animal. Stable QD-BRET probes should further facilitate their applications for both in vitro testing as well as in vivo cell tracking studies. Keywordsself-illuminating quantum dots; bioluminescence resonance energy transfer (BRET); polymeric encapsulation; molecular imaging; nanotechnology Semiconductor quantum dots (QDs) have captivated scientists and engineers over the past two decades owing to their fascinating optical and electronic properties, which are not available from either single individual molecules or bulk solids [1]. Compared with organic dyes and fluorescent proteins, semiconductor QDs offer several unique advantages, such as size-and composition-tunable emission from visible to infrared wavelengths, large absorption coefficients across a wide spectral range, and very high levels of brightness and photostability [2]. These properties make them appealing fluorescent probes for bioimaging applications including in situ cell/tissue labeling, live cell imaging and in vivo imaging [3]. However, in vivo imaging using quantum dots still faces challenges such as interferences from tissue autofluorescence [4] and paucity of light available at non-superficial tissue sites [5]. One approach to solve these problems is to use high quality near infrared (NIR) QDs [6], which is an area still under active development. Alternatively, since both problems are related to the

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Section: Discussionmentioning

confidence: 99%

Improved QD-BRET conjugates for detection and imaging

Xing

Koh

et al. 2008

Biochemical and Biophysical Research Communications

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“…4,5,[29][30][31] Nonspecific binding in tumors could nevertheless be caused either by nonspecific adsorption of the RGD peptide or by the qdot surface to tumor neovasculature. To control for this, similar peptide RAD was employed on qdots.…”

Section: Nih Public Accessmentioning

confidence: 99%

“…This makes them highly conducive to preclinical optical imaging. [1][2][3][4][5][6][7][8] Qdots have been used in living subjects to target tissue-specific vascular biomarkers 3 and cancer cells 1,2,4,5,8 and to identify sentinel lymph nodes in cancer 9-12 with the potential for © Copyright 2008 by the American Chemical Society * Corresponding author: mail, Sanjiv S. Gambhir, MD, PhD, Director, Molecular Imaging Program at Stanford (MIPS), Head, Division of Nuclear Medicine, Professor, Department of Radiology and Bio-X Program, The James H. Clark Center, 318 Campus Dr., East Wing, first Floor, Stanford, CA 94305-5427; phone, 650-725-2309; fax, 650-724-4948; sgambhir@stanford.edu. Supporting Information Available: Videos showing RGD-qdot injection and binding, RGD-qdots in normal mouse vasculature and tumor vasculature, Cy5.5-RGD block of RGD-qdots in tumor, unconjugated qdots entering the tumor vasculature, and Cy5.5 and Cy5.5-RGD leaking out of the tumor neovasculature and descriptions of nanoparticle conjugates, the tumor model, intravital microscopy, statistics, electron microscopy, and U87MG cells incubated with RGD-qdots.…”

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confidence: 99%

Real-Time Intravital Imaging of RGD−Quantum Dot Binding to Luminal Endothelium in Mouse Tumor Neovasculature

et al. 2008

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Nanoscale materials have increasingly become subject to intense investigation for use in cancer diagnosis and therapy. However, there is a fundamental dearth in cellular-level understanding of how nanoparticles interact within the tumor environment in living subjects. Adopting quantum dots (qdots) for their excellent brightness, photostability, monodispersity, and fluorescent yield, we link arginine-glycine-aspartic acid (RGD) peptides to target qdots specifically to newly formed/forming blood vessels expressing α v β 3 integrins. Using this model nanoparticle system, we exploit intravital microscopy with subcellular (∼0.5 μm) resolution to directly observe and record, for the first time, the binding of nanoparticle conjugates to tumor blood vessels in living subjects. This generalizable method enabled us to show that in this model qdots do not extravasate and, unexpectedly, that they only bind as aggregates rather than individually. This level of understanding is critical on the path toward ensuring regulatory approval of nanoparticles in humans for disease diagnostics and therapeutics. Equally vital, the work provides a platform by which to design and optimize molecularly targeted nanoparticles including quantum dots for applications in living subjects.Quantum dots (qdots) are single nanocrystal colloidal semiconductors with exceptional fluorescent properties. This makes them highly conducive to preclinical optical imaging. [1][2][3][4][5][6][7][8] Qdots have been used in living subjects to target tissue-specific vascular biomarkers 3 and cancer cells 1,2,4,5,8 and to identify sentinel lymph nodes in cancer 9-12 with the potential for © Copyright 2008 by the American Chemical Society * Corresponding author: mail, Sanjiv S. Gambhir, MD, PhD, Director, Molecular Imaging Program at Stanford (MIPS), Head, Division of Nuclear Medicine, Professor, Department of Radiology and Bio-X Program, The James H. Clark Center, 318 Campus Dr., East Wing, first Floor, Stanford, CA 94305-5427; phone, 650-725-2309; fax, 650-724-4948; sgambhir@stanford.edu. Supporting Information Available: Videos showing RGD-qdot injection and binding, RGD-qdots in normal mouse vasculature and tumor vasculature, Cy5.5-RGD block of RGD-qdots in tumor, unconjugated qdots entering the tumor vasculature, and Cy5.5 and Cy5.5-RGD leaking out of the tumor neovasculature and descriptions of nanoparticle conjugates, the tumor model, intravital microscopy, statistics, electron microscopy, and U87MG cells incubated with RGD-qdots. This material is available free of charge via the Internet at http://pubs.acs.org. In this work, we exploited intravital microscopy (IV-100, Olympus, Center Valley, PA) to examine the binding of neovascularly targeted fluorescent nanoparticles to tumor neovasculature via direct cellular-level visualization in living mice ( Figure 1a). Arginineglycine-aspartic acid (RGD) and control peptide qdot conjugates were prepared as previously described with some modifications 5 (see Figure 1b and Supporting Information for protocols)...

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“…After 24 h of probe injection, the images of the tumors are further reduced and the intensity of fluorescence is decreased. This might be due to the gradual degradation of ligands and coating layer on the surface of probe by lysosomal enzymes (18,32,33), leading to gradual decreases of the probe binding ability and gradual quenching of the fluorescent quantum dots. Our previous studies (10) have also shown that in vivo imaging can detect a minimum of 10 4 cancer cells labeled with NIRF-QDs in the presence of skin barrier, which was 100-fold higher than the minimal detection limit of CT and MRI.…”

Section: Discussionmentioning

confidence: 99%

In vivo and in situ imaging of head and neck squamous cell carcinoma using near-infrared fluorescent quantum dot probes conjugated with epidermal growth factor receptor monoclonal antibodies in mice

et al. 2012

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Abstract. In this study, we applied near-infrared fluorescent quantum dots (NIRF-QDs) for non-invasive in vivo and in situ imaging of head and neck squamous cell carcinoma (HNSCC). The U14 squamous cancer cell line with high expression of epidermal growth factor receptor (EGFR) was implanted subcutaneously into the head and neck regions of nude mice to establish HNSCC models. NIRF-QDs with an emission wavelength of 800 nm (NIRF-QD800) were conjugated with EGFR monoclonal antibodies to develop the QD800-EGFR Ab probe. In vivo and in vitro studies demonstrated that the QD800-EGFR Ab probe can specifically bind EGFR expressed on U14 cells. U14 squamous cell carcinoma in the head and neck can be clearly visualized by in vivo imaging after intravenous injection of QD800-EGFR Ab probes. The results suggested that in situ imaging using NIRF-QD-EGFR Ab probes has unique advantages and prospects for the investigation of tumor development, early diagnosis and personalized therapy of HNSCC. IntroductionNon-invasive in vivo and in situ imaging of tumor cells plays an important role in studying the occurrence and development of cancers, making early diagnosis and conducting personalized therapies. This has been a difficult area due to the lack of highly sensitive imaging substances and specific marker for each particular type of tumor. Quantum dots (QDs) were developed recently and have shown great prospect in the noninvasive imaging of tumors (1,2).QD is a type of nanocrystal composed of elements belonging to Ⅱ-Ⅵ or Ⅲ-Ⅴ groups with a diameter of 2-10 nm. In comparison to the conventional organic fluorescent dyes and fluorescent proteins, QDs have unique optical properties, e.g., broad and continuous distribution of the excitation spectrum, narrow and symmetric emission spectrum, strong fluorescence and high photochemical stability. In addition, QDs are less prone to photobleaching and the spectrum of any points from ultraviolet to the near infrared can be obtained by changing the size and composition of QDs (3,4). These optical properties are not owned by all the current fluorescent probes. Currently, QDs have been applied in the imaging of biological macromolecules and cells both in vitro and in vivo (5-7). Non-invasive in vivo imaging has been used for the investigation of tumor development (8-10), early diagnosis of cancer (10), the transportation of drugs in vivo (11), and monitoring of therapeutic responses in vivo (11)(12)(13). These studies have demonstrated the unique advantages of QDs in the imaging of cells both in vitro and in vivo. Particularly, the recently developed near-infrared fluorescent quantum dot (NIRF-QD) with an emission range of 700-900 nm has the advantage of avoiding the interference of tissue auto fluorescence (400-600 nm). NIRF-QDs have strong tissue penetration, but do not have radiation and are not harmful in vivo. Therefore, NIRF-QDs are extremely suitable for non-invasive in vivo imaging (14,15).NIRF-QDs were conjugated with prostate specific membrane antigen monoclonal antibody (PSMA), Her2 ...

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Peptide-Labeled Near-Infrared Quantum Dots for Imaging Tumor Vasculature in Living Subjects

Cited by 889 publications

References 37 publications

Improved QD-BRET conjugates for detection and imaging

Improved QD-BRET conjugates for detection and imaging

Real-Time Intravital Imaging of RGD−Quantum Dot Binding to Luminal Endothelium in Mouse Tumor Neovasculature

In vivo and in situ imaging of head and neck squamous cell carcinoma using near-infrared fluorescent quantum dot probes conjugated with epidermal growth factor receptor monoclonal antibodies in mice

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