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Supplementary methods. Supplementary Table S1. Antibodies used in immune cell characterization by flow cytometry. Supplementary Table S2. PK parameters of ALT-803 administered to cynomolgus monkeys. Supplementary Table S3. Representative clinical characteristics of cynomolgus monkeys following 4 weekly doses of ALT-803 administration (study day 26). Supplementary Table S4. Incidence of major histopathologic findings in cynomolgus monkeys following 4 weekly doses of ALT-803 administration (study day 26). Supplementary Figure 1. Comparative binding of ALT-803 to IL-15 receptors on mouse, cynomolgus monkey, and human immune cells.

Supplementary Figure 1. Purification of heterodimer after click chemistry conjugation of ALT-836-Fab and TRC105-Fab Supplementary Figure 2. MALDI-TOF mass spectra of ALT-836-Fab: [M+H]+ = 47266.0, TRC105-Fab: [M+H]+ = 47454.7, and heterodimer: exact [M+H]+ = 103504.0. Supplementary Figure 3. Flow cytometry analysis in BXPC-3 after 1 h incubation of FITC-Fab conjugates for the comparison of their in vitro targeting Supplementary Figure 4. Radiolabeling efficiency at different copper: immunoconjugate ratios were used to determine the number of NOTA per antibody fragment molecule Supplementary Figure 5. PET imaging and biodistribution of 64CuCl2 in BXPC-3 tumor-bearing mice. Supplementary Figure 6. PET imaging and quantitative ROI analysis of 64Cu-NOTA-heterodimer with TF and CD105 dual-blocking in BXPC-3 tumor-bearing mice. Supplementary Figure 7. Coronal images and transverse PET/CT images of normal nude mice at 3, 15, 24 and 30 h following injection of 64Cu-NOTA-heterodimer Supplementary Figure 8. PET ROI-derived quantification of 64Cu-NOTA-heterodimer uptake in the tumor, normal pancreas, blood pool, liver, kidney and muscle at 3 h, 15 h, 24 h and 30 h p.i. of the tracer

Movie S3 from Dual Targeting of Tissue Factor and CD105 for Preclinical PET Imaging of Pancreatic Cancer

Determination of NOTA to Fab Fragment Ratio

Purpose: Pancreatic adenocarcinoma is a highly aggressive cancer, currently treated with limited success and dismal outcomes. New diagnostic and treatment strategies offer the potential to reduce cancer mortality. Developing highly specific noninvasive imaging probes for pancreatic cancer is essential to improving diagnostic accuracy and monitoring therapeutic intervention.Experimental Design: A bispecific heterodimer was synthesized by conjugating an anti-tissue factor (TF) Fab with an anti-CD105 Fab, via the bio-orthogonal “click” reaction between tetrazine (Tz) and trans-cyclooctene (TCO). The heterodimer was labeled with 64Cu for PET imaging of nude mice bearing BXPC-3 xenograft and orthotopic pancreatic tumors.Results: PET imaging of BXPC-3 (TF/CD105+/+) xenograft tumors with 64Cu-labeled heterodimer displayed significantly enhanced tumor uptake (28.8 ± 3.2 %ID/g; n = 4; SD) at 30 hours postinjection, as compared with each of their monospecific Fab tracers (12.5 ± 1.4 and 7.1 ± 2.6 %ID/g; n = 3; SD). In addition, the activity–concentration ratio allowed for effective tumor visualization (tumor/muscle ratio 75.2 ± 9.4 at 30 hours postinjection.; n = 4; SD). Furthermore, 64Cu-NOTA-heterodimer enabled sensitive detection of orthotopic pancreatic tumor lesions with an uptake of 17.1 ± 4.9 %ID/g at 30 hours postinjection and tumor/muscle ratio of 72.3 ± 46.7.Conclusions: This study demonstrates that dual targeting of TF and CD105 provided synergistic improvements in binding affinity and tumor localization of the heterodimer. Dual-targeted imaging agents of pancreatic and other cancers may assist in diagnosing pancreatic malignancies as well as reliable monitoring of therapeutic response. Clin Cancer Res; 22(15); 3821–30. ©2016 AACR.

The exemplary progress of silica nanotechnology has attracted extensive attention across a range of biomedical applications such as diagnostics and imaging, drug delivery, and therapy of cancer and other diseases. Ultrasmall silica nanoparticles (USNs) have emerged as a particularly promising class demonstrating unique properties that are especially suitable for and have shown great promise in translational and clinical biomedical research. In this review, we discuss synthetic strategies that allow precise engineering of USNs with excellent control over size and surface chemistry, functionalization, and pharmacokinetic and toxicological profiles. We summarize the current state-of-the-art in the biomedical applications of USNs with a particular focus on select clinical studies. Finally, we illustrate long-standing challenges in the translation of inorganic nanotechnology, particularly in the context of ultrasmall nanomedicines, and provide our perspectives on potential solutions and future opportunities in accelerating the translation and widespread adoption of USN technology in biomedical research.

Plant-derived vesicles (PDVs) were attractive for therapeutic applications, including as potential nanocarriers. However, a concern with oral delivery of PDVs is whether they would remain intact in the gastrointestinal tract. We found that 82% of cabbage PDVs were destroyed under conditions mimicking the upper digestive tract. To overcome this limitation, we developed a delivery method whereby lyophilized Eudragit S-100-coated cabbage PDVs were packaged into a capsule (Cap-cPDVs). Lyophilization and suspension of PDVs in phosphate-buffered saline did not have an appreciable effect on PDV structure, number of PDVs, or therapeutic effect. However, packaging the lyophilized Eudragit S-100-coated PDVs into capsules allowed them to pass through the upper gastrointestinal tract for delivery into the colon better than did suspension of PDVs in phosphate-buffered saline. Cap-cPDVs demonstrated robust therapeutic effect in a dextran sulfate sodium-induced colitis mouse model. These findings could have broad implications for oral delivery of PDVs. Citation Format: Yuan Liu, Adrian Lankenau-Ahumada, Emine Bayraktar, Paul Schwartz, Mamur Chowdhury, Sixiang Shi, Manu M. Sebastian, Htet Khant, Natalia De Val, Zuliang Jie, Nicholas B. Jennings, Cristian Rodriguez-Aguayo, Jody Swain, Elaine Stur, Lingegowda S. Mangala, Yutuan Wu, Supriya Nagaraju, Brooke Erimas, Chun Li, Gabriel Lopez-Berestein, Janet Braam, Anil K. Sood. Enhancing oral delivery of plant-derived vesicles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2720.

Tumor heterogeneity limits the predictive value of PD-L1 expression and influences the outcomes of the immunohistochemical assay for therapy-induced changes in PD-L1 levels. This study aimed to determine the predictive value of PD-L1 for non-small cell lung carcinoma (NSCLC), thereby developing imaging agents to non-invasively image and examine the effect of the therapeutic response to PD-L1 blockade therapy.A cohort of 102 patients with lung cancer was analyzed, and the prognostic significance of PD-L1 expression level was investigated. Recombinant human PD-1 ECD protein (rhPD1) was expressed, purified, and labeled withPD-L1 was proved to be a good prognosis marker for NSCLC, and its expression was correlated with the histology of NSCLC. PET imaging revealed high tumor accumulation ofWe identified PD-L1 as a good prognosis marker for surgically resected NSCLC and developed the PET tracer

Exosomes have attracted tremendous attention due to their important role in physiology, pathology, and oncology, as well as promising potential in biomedical applications. Although great efforts have been dedicated to investigating their biological properties and applications as natural cancer drug-delivery systems, the systemic biodistribution of exosomes remains underexplored. In addition, exosome-based drug delivery is inevitably hindered by the robust liver clearance, leading to suboptimal tumor retention and therapeutic efficiency. In this study, we report one of the first examples using in vivo positron emission tomography (PET) for noninvasive monitoring of copper-64 (64Cu)-radiolabeled polyethylene glycol (PEG)-modified exosomes, achieving excellent imaging quality and quantitative measurement of blood residence and tumor retention. PEGylation not only endowed exosomes with a superior pharmacokinetic profile and great accumulation in the tumor versus traditionally reported native exosomes but also reduced premature hepatic sequestration and clearance of exosomes, findings that promise enhanced therapeutic delivery efficacy and safety in future studies. More importantly, this study provides important guidelines about surface engineering, radiochemistry, and molecular imaging in obtaining accurate and quantitative biodistribution information on exosomes, which may benefit future exploration in the realm of exosomes.

Recently, drug delivery systems based on nanotechnology have received great attention in cancer therapeutics and diagnostics since they can not only improve the treatment efficacy but also reduce the side effects. Among them, mesoporous silica nanoparticles (MSNs) with large surface area, high pore volume, tunable pore size, abundant surface chemistry, and acceptable biocompatibility exhibit unique advantages and are considered as promising candidates for cancer diagnosis and therapy. In this review, we update the recent progress on MSN-based systems for cancer treatment purposes. We also discuss the drug loading mechanism of MSNs, stimuli-responsive drug release, and surface modification strategies for improving biocompatibility, and targeting functionalities. STATEMENT OF SIGNIFICANCE: The development of MSN-based delivery systems that can be used in both diagnosis and treatment of cancer has attracted tremendous interest in the past decade. MSN-based delivery systems can improve therapeutic efficacy and reduce cytotoxicity to normal tissue. To further improve the in vivo properties of MSNs and potential translation to the clinics, it is critical to design MSNs with appropriate surface engineering and desirable cancer targeting. This review is intended to provide the readers a comprehensive background of the vast literature till date on silica-based drug delivery systems, and to inspire further innovations in silica nanomedicine in the future.

Although multifunctional inorganic nanoparticles have been extensively explored for effective cancer diagnosis and therapy, their clinical translation has been greatly impeded because of significant uptake in the reticuloendothelial system and concerns about potential toxicity. In this study, we uncovered the thermosensitive biodegradability of CuS nanoparticles, which have classically been considered as stable in bulk state. Polyethylene glycol (PEG)-coated CuS nanoparticles (CuS-PEG) were well preserved at 4 oC but were rapidly degraded at 37 oC within 1 week in both in vitro and in vivo tests. Furthermore, real-time multispectral optoacoustic tomography, which is more convenient and accurate than traditional ex vivo analysis, was successfully employed to noninvasively demonstrate the biodegradability of CuS-PEG nanoparticles and dynamically monitor their tumor imaging capacity. The temperature-dependent controllable degradation profile and excellent tumor retention of CuS-PEG nanoparticles endows them with great potential for clinical applications since it ensures that the nanoparticles remain intact during production, transportation, and storage but degrade and clear from the body at physiological temperature after accomplishing sufficient diagnosis and therapeutic operations.

Generation of durable tumor-specific immune response without isolation and expansion of dendritic cells or T cells ex vivo remains a challenge. In this study, we investigated the impact of nanoparticle-mediated photothermolysis in combination with checkpoint inhibition on the induction of systemic antitumor immunity. Photothermolysis based on near-infrared light-absorbing copper sulfide nanoparticles and 15-ns laser pulses combined with the immune checkpoint inhibitor anti-PD-1 antibody (αPD-1) increased tumor infiltration by antigen-presenting cells and CD8-positive T lymphocytes in the B16-OVA mouse model. Moreover, combined photothermolysis, polymeric conjugate of the Toll-like receptor 9 agonist CpG, and αPD-1 significantly prolonged mouse survival after re-inoculation of tumor cells at a distant site compared to individual treatments alone in the poorly immunogenic syngeneic ID8-ip1-Luc ovarian tumor model. Thus, photothermolysis is a promising interventional technique that synergizes with Toll-like receptor 9 agonists and immune checkpoint inhibitors to enhance the abscopal effect in tumors.

Copper sulfide (CuS) nanoparticles have been considered one of the most clinical relevant nanosystems because of their straightforward chemistry, small particle size, low toxicity, and intrinsic theranostic characteristics. In our previous studies, radioactive [64Cu]CuS nanoparticles were successfully developed to be used as efficient radiotracers for positron emission tomography and for photothermal ablation therapy of cancer cells using near-infrared laser irradiation. However, the major challenge of CuS nanoparticles as a theranostic platform is the lack of a means for effective targeted delivery to the tumor site. To overcome this challenge, we designed and synthesized angiogenesis-targeting [64Cu]CuS nanoparticles, which are coupled with cyclic RGDfK peptide [c(RGDfK)] through polyethylene glycol (PEG) linkers using click chemistry. In assessing their tumor-targeting efficacy, we found that the tumor uptakes of [64Cu]CuS-PEG-c(RGDfK) nanoparticles at 24 h after intravenous injection were significantly greater (8.6% ± 1.4% injected dose/gram of tissue) than those of nontargeted [64Cu]CuS-PEG nanoparticles (4.3% ± 1.2% injected dose/gram of tissue, p < 0.05). Irradiation of tumors in mice administered [64Cu]CuS-PEG-c(RGDfK) nanoparticles induced 98.7% necrotic areas. In contrast, irradiation of tumors in mice administered nontargeted CuS-PEG nanoparticles induced 59% necrotic areas ( p < 0.05). The angiogenesis-targeting [64Cu]CuS nanoparticles may serve as a promising platform for image-guided ablation therapy with high efficacy and minimal side effects in future clinical translation of this novel class of multifunctional nanomaterials.

ALT-803 is a fusion protein complex consisting of an interleukin (IL)-15 superagonist and a dimeric IL-15 receptor alpha sushi domain IgG1 Fc fusion protein. When administered to mice, ALT-803 is capable of inducing natural killer (NK) and CD8(+) T cell proliferation and activation, and effectively promoting potent anti-tumor responses. Currently, ALT-803 is in clinical trials for treatment of various solid tumors and hematological malignancies. In the initial phase of these clinical studies, intravenous (iv) injection was used according to the route used in pre-clinical efficacy studies. In order to evaluate the possible advantage of subcutaneous (sc) injection versus iv injection, this study compared the biological activity of the two treatment regimens of ALT-803 in pre-clinical in vivo models. The pharmacokinetics, immune stimulation, and anti-tumor efficacy of iv and sc injection routes of ALT-803 in C57BL/6 mice were compared. The half-life of ALT-803 was 7.5 h for iv versus 7.7 h for sc with the maximal detected serum concentration of ALT-803 to be 3926 ng/ml at 0.5 h time-point following iv injection versus 495 ng/ml at 16 h post sc injection. Biodistribution studies indicated that sc ALT-803, similarly to iv ALT-803 as previously reported, has a greater tissue distribution and longer residence time in lymphoid tissues compared to recombinant IL-15. Notably, ALT-803 when administered either iv or sc induced comparable proliferation and activation of CD8(+) T and NK cells and resulted in similar reductions of tumor burden. A toxicity study of mice receiving multiple injections of ALT-803 for 4 weeks by iv or sc routes revealed equivalent immune-related changes. The gradual absorbance into the blood stream and lower maximal blood levels of ALT-803 in sc-injected mice, along with similar anti-tumor efficacy support the administration of ALT-803 by sc injection in patients with various malignancies and infectious diseases.

Silica nanoparticles have been one of the most promising nanosystems for biomedical applications due to their facile surface chemistry and non-toxic nature. However, it is still challenging to effectively deliver them into tumor sites and noninvasively visualize their in vivo biodistribution with excellent sensitivity and accuracy for effective cancer diagnosis. In this study, we design a yolk/shell-structured silica nanosystem 64Cu-NOTA-QD@HMSN-PEG-TRC105, which can be employed for tumor vasculature targeting and dual-modality PET/optical imaging, leading to superior targeting specificity, excellent imaging capability and more reliable diagnostic outcomes. By combining vasculature targeting, pH-sensitive drug delivery, and dual-modality imaging into a single platform, as-designed yolk/shell-structured silica nanosystems may be employed for the future image-guided tumor-targeted drug delivery, to further enable cancer theranostics.

Multifunctional yolk/shell-structured hybrid nanomaterials have attracted increasing interest as theranostic nanoplatforms for cancer imaging and therapy. However, because of the lack of suitable surface engineering and tumor targeting strategies, previous research has focused mainly on nanostructure design and synthesis with few successful examples showing active tumor targeting after systemic administration. In this study, we report the general synthetic strategy of chelator-free zirconium-89 (89Zr)-radiolabeled, TRC105 antibody-conjugated, silica-based yolk/shell hybrid nanoparticles for in vivo tumor vasculature targeting. Three types of inorganic nanoparticles with varying morphologies and sizes were selected as the internal cores, which were encapsulated into single hollow mesoporous silica nanoshells to form the yolk/shell-structured hybrid nanoparticles. As a proof-of-concept, we demonstrated successful surface functionalization of the nanoparticles with polyethylene glycol, TRC105 antibody (specific forCD105/endoglin), and 89Zr (a positron-emitting radioisotope), and enhanced in vivo tumor vasculature-targeted positron emission tomography imaging in 4T1murine breast tumor-bearing mice. This strategy could be applied to the synthesis of other types of yolk/shell theranostic nanoparticles for tumor-targeted imaging and drug delivery.

Manganese-based nanoparticles (NPs) have recently attracted much attention in the field of biomedical imaging due to their impressive enhanced T1 contrast ability. Although the reported manganese-based NPs have exhibited good imaging capabilities as contrast agents, it is still urgent to develop novel multifunctional manganese-based imaging probes for future biomedical imaging, especially PET/MRI probes. Herein, we present chelator-free zirconium-89 (89Zr, t1/2: 78.4 h) labeling of manganese oxide NPs (Mn3O4@PEG) with ~78% labeling yield and good stability. Serial positron emission tomography (PET) and magnetic resonance imaging (MRI) studies non-invasively assessed the biodistribution patterns of the NPs and the feasibility of in vivo dual-modality imaging and lymph-node mapping. Since Mn3O4 NPs exhibited desirable properties for enhanced T1 imaging and the simplicity of chelator-free radiolabeling, [89Zr]Mn3O4@PEG NPs offer a novel, simple, safe and accurate nanoplatforms for future precise cancer imaging and diagnosis.

Purpose: Among the treatment options for pancreatic ductal adenocarcinoma (PDAC) are antibodies against the programmed cell death receptor 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway. Positron emission tomography (PET) has been successfully used to assess PD-1/PD-L1 signaling in subcutaneous tumor models, but orthotopic tumor models are increasingly being recognized as a better option to accurately recapitulate human disease. However, when PET radiotracers have high uptake in the liver and spleen, it can obscure signals from the adjacent pancreas, making visualization of the response in orthotopic pancreatic tumors technically challenging. In this study, we first investigated the impact of radioisotope chelators on the biodistribution of 64Cu-labeled anti-PD-1 and anti-PD-L1 antibodies and compared the distribution profiles of anti-PD-1 and anti-PD-L1 antibodies. We then tested the hypothesis that co-injection of unlabeled antibodies reduces uptake of 64Cu-labeled anti-PD-L1 antibodies in the spleen and thereby permits accurate delineation of orthotopic pancreatic tumors in mice. Procedures: We established subcutaneous and orthotopic mouse models of PDAC using KRAS* murine pancreatic cancer cells with a doxycycline-inducible mutation of KRASG12D. We then (1) compared the biodistribution of 64Cu-labeled anti-PD-1 with 2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (p-SCN-Bn-DOTA) and 2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) used as the chelators in the orthotopic model; (2) compared the biodistribution of [64Cu]Cu-NOTA-anti-PD-1 and [64Cu]Cu-NOTA-anti-PD-L1 in the orthotopic model; and (3) imaged subcutaneous and orthotopic KRAS* tumors with [64Cu]Cu-NOTA-anti-PD-L1 with and without co-injection of unlabeled anti-PD-L1 as the blocking agent. Results: [64Cu]Cu-NOTA-anti-PD-L1 was a promising imaging probe. By co-injection of an excess of unlabeled anti-PD-L1, background signals of [64Cu]Cu-NOTA-anti-PD-L1 from the spleen were significantly reduced, leading to a clear delineation of orthotopic pancreatic tumors. Conclusions: Co-injection with unlabeled anti-PD-L1 is a useful method for PET imaging of PD-L1 expression in orthotopic pancreatic cancer models.

Purpose: Pancreatic adenocarcinoma is a highly aggressive cancer, currently treated with limited success and dismal outcomes. New diagnostic and treatment strategies offer the potential to reduce cancer mortality. Developing highly specific noninvasive imaging probes for pancreatic cancer is essential to improving diagnostic accuracy and monitoring therapeutic intervention. Experimental Design: A bispecific heterodimer was synthesized by conjugating an anti-tissue factor (TF) Fab with an anti-CD105 Fab, via the bio-orthogonal “click” reaction between tetrazine (Tz) and trans-cyclooctene (TCO). The heterodimer was labeled with 64Cu for PET imaging of nude mice bearing BXPC-3 xenograft and orthotopic pancreatic tumors. Results: PET imaging of BXPC-3 (TF/CD105+/+) xenograft tumors with 64Cu-labeled heterodimer displayed significantly enhanced tumor uptake (28.8 ± 3.2 %ID/g; n = 4; SD) at 30 hours postinjection, as compared with each of their monospecific Fab tracers (12.5 ± 1.4 and 7.1 ± 2.6 %ID/g; n = 3; SD). In addition, the activity–concentration ratio allowed for effective tumor visualization (tumor/muscle ratio 75.2 ± 9.4 at 30 hours postinjection.; n = 4; SD). Furthermore, 64Cu-NOTA-heterodimer enabled sensitive detection of orthotopic pancreatic tumor lesions with an uptake of 17.1 ± 4.9 %ID/g at 30 hours postinjection and tumor/muscle ratio of 72.3 ± 46.7. Conclusions: This study demonstrates that dual targeting of TF and CD105 provided synergistic improvements in binding affinity and tumor localization of the heterodimer. Dual-targeted imaging agents of pancreatic and other cancers may assist in diagnosing pancreatic malignancies as well as reliable monitoring of therapeutic response. Clin Cancer Res; 22(15); 3821–30. ©2016 AACR.

In September 2013, China put forward the "New Silk Road Economic Belt" cooperation initiative and in October of the same year, China put forward the "21st Century Maritime Silk Road" cooperation initiative again. Due to the huge economic differences among countries in "One Belt and One Road", it is necessary to conduct in-depth analysis of the differences in each economic zone. In this way, it is convenient for countries to carry out in-depth economic cooperation and convert resource economy and technological advantages into products needed by each country. Therefore, this article will conduct an empirical analysis of the differences in the "Belt and Road" economic zone based on matlab software to provide references for relevant personnel.

Multifunctional yolk/shell-structured hybrid nanomaterials have attracted increasing interest as theranostic nanoplatforms for cancer imaging and therapy. However, because of the lack of suitable surface engineering and tumor targeting strategies, previous research has focused mainly on nanostructure design and synthesis with few successful examples showing active tumor targeting after systemic administration. In this study, we report the general synthetic strategy of chelator-free zirconium-89 ((89)Zr)-radiolabeled, TRC105 antibody-conjugated, silica-based yolk/shell hybrid nanoparticles for in vivo tumor vasculature targeting. Three types of inorganic nanoparticles with varying morphologies and sizes were selected as the internal cores, which were encapsulated into single hollow mesoporous silica nanoshells to form the yolk/shell-structured hybrid nanoparticles. As a proof-of-concept, we demonstrated successful surface functionalization of the nanoparticles with polyethylene glycol, TRC105 antibody (specific forCD105/endoglin), and (89)Zr (a positron-emitting radioisotope), and enhanced in vivo tumor vasculature-targeted positron emission tomography imaging in 4T1murine breast tumor-bearing mice. This strategy could be applied to the synthesis of other types of yolk/shell theranostic nanoparticles for tumor-targeted imaging and drug delivery.

Copper sulfide (CuS) nanoparticles have been considered one of the most clinical relevant nanosystems because of their straightforward chemistry, small particle size, low toxicity, and intrinsic theranostic characteristics. In our previous studies, radioactive [(64)Cu]CuS nanoparticles were successfully developed to be used as efficient radiotracers for positron emission tomography and for photothermal ablation therapy of cancer cells using near-infrared laser irradiation. However, the major challenge of CuS nanoparticles as a theranostic platform is the lack of a means for effective targeted delivery to the tumor site. To overcome this challenge, we designed and synthesized angiogenesis-targeting [(64)Cu]CuS nanoparticles, which are coupled with cyclic RGDfK peptide [c(RGDfK)] through polyethylene glycol (PEG) linkers using click chemistry. In assessing their tumor-targeting efficacy, we found that the tumor uptakes of [(64)Cu]CuS-PEG-c(RGDfK) nanoparticles at 24 h after intravenous injection were significantly greater (8.6%±1.4% injected dose/gram of tissue) than those of nontargeted [(64)Cu]CuS-PEG nanoparticles (4.3%±1.2% injected dose/gram of tissue, p < 0.05). Irradiation of tumors in mice administered [(64)Cu]CuS-PEG-c(RGDfK) nanoparticles induced 98.7% necrotic areas. In contrast, irradiation of tumors in mice administered non-targeted CuS-PEG nanoparticles induced 59% necrotic areas (p < 0.05). The angiogenesis-targeting [(64)Cu]CuS nanoparticles may serve as a promising platform for image-guided ablation therapy with high efficacy and minimal side effects in future clinical translation of this novel class of multifunctional nanomaterials.

Manganese-based nanoparticles (NPs) have recently attracted much attention in the field of biomedical imaging due to their impressive enhanced T(1) contrast ability. Although the reported manganese-based NPs have exhibited good imaging capabilities as contrast agents, it is still urgent to develop novel multifunctional manganese-based imaging probes for future biomedical imaging, especially PET/MRI probes. Herein, we present chelator-free zirconium-89 ((89)Zr, t(1/2): 78.4 h) labeling of manganese oxide NPs (Mn(3)O(4)@PEG) with ~78% labeling yield and good stability. Serial positron emission tomography (PET) and magnetic resonance imaging (MRI) studies non-invasively assessed the biodistribution patterns of the NPs and the feasibility of in vivo dual-modality imaging and lymph-node mapping. Since Mn(3)O(4) NPs exhibited desirable properties for enhanced T(1) imaging and the simplicity of chelator-free radiolabeling, [(89)Zr]Mn(3)O(4)@PEG NPs offer a novel, simple, safe and accurate nanoplatforms for future precise cancer imaging and diagnosis.

IL15, a potent stimulant of CD8+ T cells and natural killer (NK) cells, is a promising cancer immunotherapeutic. ALT-803 is a complex of an IL15 superagonist mutant and a dimeric IL15 receptor αSu/Fc fusion protein that was found to exhibit enhanced biologic activity in vivo, with a substantially longer serum half-life than recombinant IL15. A single intravenous dose of ALT-803, but not IL15, eliminated well-established tumors and prolonged survival of mice bearing multiple myeloma. In this study, we extended these findings to demonstrate the superior antitumor activity of ALT-803 over IL15 in mice bearing subcutaneous B16F10 melanoma tumors and CT26 colon carcinoma metastases. Tissue biodistribution studies in mice also showed much greater retention of ALT-803 in the lymphoid organs compared with IL15, consistent with its highly potent immunostimulatory and antitumor activities in vivo. Weekly dosing with 1 mg/kg ALT-803 in C57BL/6 mice was well tolerated, yet capable of increasing peripheral blood lymphocyte, neutrophil, and monocyte counts by >8-fold. ALT-803 dose-dependent stimulation of immune cell infiltration into the lymphoid organs was also observed. Similarly, cynomolgus monkeys treated weekly with ALT-803 showed dose-dependent increases of peripheral blood lymphocyte counts, including NK, CD4+, and CD8+ memory T-cell subsets. In vitro studies demonstrated ALT-803–mediated stimulation of mouse and human immune cell proliferation and IFNγ production without inducing a broad-based release of other proinflammatory cytokines (i.e., cytokine storm). Based on these results, a weekly dosing regimen of ALT-803 has been implemented in multiple clinical studies to evaluate the dose required for effective immune cell stimulation in humans. Cancer Immunol Res; 4(1); 49–60. ©2015 AACR.

UNLABELLED The critical challenge in abdominal aortic aneurysm (AAA) research is the accurate diagnosis and assessment of AAA progression. Angiogenesis is a pathologic hallmark of AAA, and CD105 is highly expressed on newly formed vessels. Our goal was to use (64)Cu-labeled anti-CD105 antibody Fab fragment for noninvasive assessment of angiogenesis in the aortic wall in a murine model of AAA. METHODS Fab fragment of TRC105, a mAb that specifically binds to CD105, was generated by enzymatic papain digestion and conjugated to NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) for (64)Cu labeling. The binding affinity/specificity of NOTA-TRC105-Fab was evaluated by flow cytometry and various ex vivo studies. BALB/c mice were anesthetized and treated with calcium phosphate to induce AAA and underwent weekly PET scans using (64)Cu-NOTA-TRC105-Fab. Biodistribution and autoradiography studies were also performed to confirm the accuracy of PET results. RESULTS NOTA-TRC105-Fab exhibited high purity and specifically bound to CD105 in vitro. Uptake of (64)Cu-NOTA-TRC105-Fab increased from a control level of 3.4 ± 0.1 to 9.5 ± 0.4 percentage injected dose per gram (%ID/g) at 6 h after injection on day 5 and decreased to 7.2 ± 1.4 %ID/g on day 12, which correlated well with biodistribution and autoradiography studies (i.e., much higher tracer uptake in AAA than normal aorta). Of note, enhanced AAA contrast was achieved, due to the minimal background in the abdominal area of mice. Degradation of elastic fibers and highly expressed CD105 were observed in ex vivo studies. CONCLUSION (64)Cu-NOTA-TRC105-Fab cleared rapidly through the kidneys, which enabled noninvasive PET imaging of the aorta with enhanced contrast and showed increased angiogenesis (CD105 expression) during AAA. (64)Cu-NOTA-TRC105-Fab PET may potentially be used for future diagnosis and prognosis of AAA.

The hepatocyte growth factor (HGF) and its receptor, c-Met, are actively involved in tumor progression and metastasis and are closely associated with a poor prognostic outcome for cancer patients. Thus, the development of PET agents that can assess c-Met expression would be extremely useful for diagnosing cancer and subsequently monitoring response to c-Met–targeted therapies. Here, we report the characterization of recombinant human HGF (rh-HGF) as a PET tracer for detection of c-Met expression in vivo. Methods: rh-HGF was expressed in human embryonic kidney 293 cells and purified by nickel-nitrilotriacetic acid affinity chromatography. The concentrated rh-HGF was conjugated to 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid and labeled with 64Cu. c-Met binding evaluation by flow cytometry was performed on both U87MG and MDA-MB-231 cell lines, which have a high level and a low level, respectively, of c-Met. PET imaging and biodistribution studies were performed on nude mice bearing U87MG and MDA-MB-231 xenografted tumors. Results: The rh-HGF expression yield was 150–200 μg of protein per 5 × 106 cells after a 48-h transfection, with purity of approximately 85%–90%. Flow cytometry examination confirmed that rh-HGF had a strong and specific capacity to bind to c-Met. After 64Cu labeling, PET imaging revealed specific and prominent uptake of 64Cu-NOTA-rh-HGF in c-Met–positive U87MG tumors (percentage injected dose per gram, 6.8 ± 1.8 at 9 h after injection) and significantly lower uptake in c-Met–negative MDA-MB-231 tumors (percentage injected dose per gram, 1.8 ± 0.6 at 9 h after injection). The fact that sonication-denatured rh-HGF had significantly lower uptake in U87MG tumors, along with histology analysis, confirmed the c-Met specificity of 64Cu-NOTA-rh-HGF. Conclusion: This study provided initial evidence that 64Cu-NOTA-rh-HGF visualizes c-Met expression in vivo, an application that may prove useful for c-Met–targeted cancer therapy.

Actively targeted theranostic nanomedicine may be the key for future personalized cancer management. Although numerous types of theranostic nanoparticles have been developed in the past decade for cancer treatment, challenges still exist in the engineering of biocompatible theranostic nanoparticles with highly specific in vivo tumor targeting capabilities. Here, we report the design, synthesis, surface engineering, and in vivo active vasculature targeting of a new category of theranostic nanoparticle for future cancer management. Water-soluble photothermally sensitive copper sulfide nanoparticles were encapsulated in biocompatible mesoporous silica shells, followed by multistep surface engineering to form the final theranostic nanoparticles. Systematic in vitro targeting, an in vivo long-term toxicity study, photothermal ablation evaluation, in vivo vasculature targeted imaging, biodistribution and histology studies were performed to fully explore the potential of as-developed new theranostic nanoparticles.

Selective overexpression of follicle-stimulating hormone receptor (FSHR) inside the vascular endothelium of tumors has been confirmed to play critical roles in angiogenesis, tumor invasion, and metastases. The expression level of FSHR correlates strongly with the response of tumors to antiangiogenic therapies. In this study, an immunoPET tracer was developed for imaging of FSHR in different cancer types. A monoclonal antibody (FSHR-mAb) against FSHR was conjugated with S-2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) and used for subsequent (64)Cu-labeling. NOTA-FSHR-mAb preserved FSHR specificity/affinity, confirmed by flow cytometry measurements. (64)Cu-labeling was successfully conducted with decent yields (∼25%) and high specific activity (0.93 GBq/mg). The uptake of (64)Cu-NOTA-FSHR-mAb was 3.6 ± 0.8, 13.2 ± 0.7, and 14.6 ± 0.4 %ID/g in FSHR-positive CAOV-3 tumors at 4, 24, and 48 h postinjection, respectively (n = 3), significantly higher (p < 0.05) than that in FSHR-negative SKOV-3 tumors (2.3 ± 1.2, 8.0 ± 0.9, and 9.1 ± 1.3 %ID/g at 4, 24, and 48 h postinjection, respectively (n = 3)) except at 4 h p.i. FSHR-relevant uptake of (64)Cu-NOTA-FSHR-mAb was also readily observed in other tumor types (e.g., triple-negative breast tumor MDA-MB-231 or prostate tumor PC-3). Histology studies showed universal FSHR expression in microvasculature of these four tumor types and also prominent expression in tumor cells of CAOV-3, PC-3, and MDA-MB-231. Correlations between tumor FSHR level and uptake of (64)Cu-NOTA-FSHR-mAb were witnessed in this study. FSHR-specific uptake of (64)Cu-NOTA-FSHR mAb in different tumors enables its applicability for future cancer theranostic applications and simultaneously establishes FSHR as a promising clinical target for cancer.

Theranostics for in vivo cancer diagnosis and treatment generally requires well-designed nanoscale platforms with multiple integrated functionalities. In this study, we uncover that functionalized iron oxide nanoparticles (IONPs) could be self-assembled on the surface of two-dimensional MoS2 nanosheets via sulfur chemistry, forming MoS2-IO nanocomposites, which are then modified with two types of polyethylene glycol (PEG) to acquire enhanced stability in physiological environments. Interestingly, (64)Cu, a commonly used positron-emitting radioisotope, could be firmly adsorbed on the surface of MoS2 without the need of chelating molecules, to enable in vivo positron emission tomography (PET) imaging. On the other hand, the strong near-infrared (NIR) and superparamagnetism of MoS2-IO-PEG could also be utilized for photoacoustic tomography (PAT) and magnetic resonance (MR) imaging, respectively. Under the guidance by such triple-modal imaging, which uncovers efficient tumor retention of MoS2-IO-(d)PEG upon intravenous injection, in vivo photothermal therapy is finally conducted, achieving effective tumor ablation in an animal tumor model. Our study highlights the promise of constructing multifunctional theranostic nanocomposites based on 2D transitional metal dichalcogenides for multimodal imaging-guided cancer therapy.

Manganese oxide nanoparticles (Mn3O4 NPs) have attracted a great deal of attention in the field of biomedical imaging because of their ability to create an enhanced imaging signal in MRI as novel potent T1 contrast agents. In this study, we present tumor vasculature-targeted imaging in mice using Mn3O4 NPs through conjugation to the anti-CD105 antibody TRC105 and radionuclide copper-64 (64Cu, t1/2: 12.7 h). The Mn3O4 conjugated NPs, 64Cu-NOTA-Mn3O4@PEG-TRC105, exhibited sufficient stability in vitro and in vivo. Serial positron emission tomography (PET) and magnetic resonance imaging (MRI) studies evaluated the pharmacokinetics and demonstrated targeting of 64Cu-NOTA-Mn3O4@PEG-TRC105 to 4T1 murine breast tumors in vivo, compared to 64Cu-NOTA-Mn3O4@PEG. The specificity of 64Cu-NOTA-Mn3O4@PEG-TRC105 for the vascular marker CD105 was confirmed through in vivo, in vitro, and ex vivo experiments. Since Mn3O4 conjugated NPs exhibited desirable properties for T1 enhanced imaging and low toxicity, the tumor-specific Mn3O4 conjugated NPs reported in this study may serve as promising multifunctional nanoplatforms for precise cancer imaging and diagnosis.

This chapter introduces the synthesis and applications of several heterostructures grown through the epitaxial process, including core/shell quantum dots (QD), core/shell upconversion nanoparticles and gold-based heterostructures. The heterostructured nanoparticles can be generated either by non-epitaxial or epitaxial techniques. In the non-epitaxial approach, the heterostructures are prepared by polycrystalline or amorphous growth process without matching of the lattice, covalent conjugation of surface functional groups, or physical absorption. QDs are nanocrystals made of semiconductor materials with a few hundred or a few thousand atoms. Among core/shell QDs, CdSe/ZnS heterostructure is one of the most commonly studied nanosystems, which was first reported in 1996. Optical imaging possesses numerous advantages, such as high sensitivity, low cost and short acquisition time, QDs and other optical imaging probes face a significant challenge for in vivo applications due to their limited tissue penetration.

Macrocyclic chelators have been widely employed in the realm of nanoparticle-based positron emission tomography (PET) imaging, whereas its accuracy remains questionable. Here, we found that 64Cu can be intrinsically labeled onto nanographene based on interactions between Cu and the π electrons of graphene without the need of chelator conjugation, providing a promising alternative radiolabeling approach that maintains the native in vivo pharmacokinetics of the nanoparticles. Due to abundant π bonds, reduced graphene oxide (RGO) exhibited significantly higher labeling efficiency in comparison with graphene oxide (GO) and exhibited excellent radiostability in vivo. More importantly, nonspecific attachment of 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) on nanographene was observed, which revealed that chelator-mediated nanoparticle-based PET imaging has its inherent drawbacks and can possibly lead to erroneous imaging results in vivo.

The vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) signaling cascade plays a critical role in tumor angiogenesis and metastasis and has been correlated with several poorly prognostic cancers such as malignant gliomas. Although a number of anti-VEGFR therapies have been conceived, inefficient drug administration still limits their therapeutic efficacy and raises concerns of potential side effects. In the present work, we propose the use of uniform mesoporous silica nanoparticles (MSNs) for VEGFR targeted positron emission tomography imaging and delivery of the anti-VEGFR drug (i.e., sunitinib) in human glioblastoma (U87MG) bearing murine models. MSNs were synthesized, characterized and modified with polyethylene glycol, anti-VEGFR ligand VEGF121 and radioisotope (64)Cu, followed by extensive in vitro, in vivo and ex vivo studies. Our results demonstrated that a significantly higher amount of sunitinib could be delivered to the U87MG tumor by targeting VEGFR when compared with the non-targeted counterparts. The as-developed VEGF121-conjugated MSN could become another attractive nanoplatform for the design of future theranostic nanomedicine.

Insulin-like growth factor 1 receptor (IGF1R) plays an important role in proliferation, apoptosis, angiogenesis, and tumor invasion. The expression level of IGF1R is related to resistance to several targeted therapies. The goal of this study was to develop an immunoPET tracer for imaging of IGF1R in prostate cancer. Murine antibodies against human IGF1R were generated in BALB/c mice, which were screened in IGF1R-positive MCF-7 cells using flow cytometry as well as biodistribution studies with multiple (64)Cu-labeled antibody clones. The antibody production method we adopted could readily produce milligram quantities of anti-IGF1R antibodies for in vivo studies. One antibody clone (1A2G11) with the highest affinity for IGF1R was selected and conjugated to NOTA for (64)Cu-labeling. NOTA-1A2G11 maintained IGF1R specificity/avidity based on flow cytometry. (64)Cu-labeling was achieved with good yield (50%) and high specific activity (1 Ci/μmol). Serial PET imaging revealed that uptake of (64)Cu-NOTA-1A2G11 was 2.8 ± 0.7, 10.2 ± 2.6, and 9.6 ± 1.7 %ID/g in IGF1R-positive DU-145 tumors at 4, 24, and 48 h postinjection, respectively (n = 3), significantly higher than that in IGF1R-negative LNCaP tumors (3 %ID/g at each time point) except at 4 h postinjection. Histology studies showed strong correlations between IGF1R expression level in the prostate cancer tumor tissues and tumor uptake of (64)Cu-NOTA-1A2G11. Prominent, persistent, and IGF1R-specific uptake of (64)Cu-NOTA-1A2G11 in IGF1R-positive prostate tumors holds strong potential for future cancer diagnosis, prognosis, and therapy using this antibody.

Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications.

Brush-shaped amphiphilic block copolymers were conjugated with a monoclonal antibody against CD105 (i.e., TRC105) and a macrocyclic chelator for (64)Cu-labeling to generate multifunctional theranostic unimolecular micelles. The backbone of the brush-shaped amphiphilic block copolymer was poly(2-hydroxyethyl methacrylate) (PHEMA) and the side chains were poly(L-lactide)-poly(ethylene glycol) (PLLA-PEG). The doxorubicin (DOX)-loaded unimolecular micelles showed a pH-dependent drug release profile and a uniform size distribution. A significantly higher cellular uptake of TRC105-conjugated micelles was observed in CD105-positive human umbilical vein endothelial cells (HUVEC) than nontargeted micelles due to CD105-mediated endocytosis. In contrast, similar and extremely low cellular uptake of both targeted and nontargeted micelles was observed in MCF-7 human breast cancer cells (CD105-negative). The difference between the in vivo tumor accumulation of (64)Cu-labeled TRC105-conjugated micelles and that of nontargeted micelles was studied in 4T1 murine breast tumor-bearing mice, by serial positron emission tomography (PET) imaging and validated by biodistribution studies. These multifunctional unimolecular micelles offer pH-responsive drug release, noninvasive PET imaging capability, together with both passive and active tumor-targeting abilities, thus making them a desirable nanoplatform for cancer theranostics.

Hollow mesoporous silica nanoparticles (HMSNs), with a large cavity inside each original mesoporous silica nanoparticle (MSN), have recently gained increasing interest due to their tremendous potential for cancer imaging and therapy. The last several years have witnessed a rapid development in engineering of functionalized HMSNs (i.e. f-HMSNs) with various types of inorganic functional nanocrystals integrated into the system for imaging and therapeutic applications. In this review article, we summarize the recent progress in the design and biological applications of f-HMSNs, with a special emphasis on molecular imaging. Commonly used synthetic strategies for the generation of high quality HMSNs will be discussed in detail, followed by a systematic review of engineered f-HMSNs for optical, positron emission tomography, magnetic resonance, and ultrasound imaging in preclinical studies. Lastly, we also discuss the challenges and future research directions regarding the use of f-HMSNs for cancer imaging and therapy.

Polyethylene glycol (PEG) surface modification is one of the most widely used approaches to improve the solubility of inorganic nanoparticles, prevent their aggregation and prolong their in vivo blood circulation half-life. Herein, we developed double-PEGylated biocompatible reduced graphene oxide nanosheets anchored with iron oxide nanoparticles (RGO-IONP-(1st)PEG-(2nd)PEG). The nanoconjugates exhibited a prolonged blood circulation half-life (∼27.7 h) and remarkable tumor accumulation (11 %ID g(-1)) via an enhanced permeability and retention (EPR) effect. Due to the strong near-infrared absorbance and superparamagnetism of RGO-IONP-(1st)PEG-(2nd)PEG, multimodality imaging combining positron emission tomography (PET) imaging with magnetic resonance imaging (MRI) and photoacoustic (PA) imaging was successfully achieved. The promising results suggest the great potential of these nanoconjugates for multi-dimensional and more accurate tumor diagnosis and therapy in the future.

Optical imaging has been the primary imaging modality for nearly all of the renal clearable nanoparticles since 2007. Due to the tissue depth penetration limitation, providing accurate organ kinetics non-invasively has long been a huge challenge. Although a more quantitative imaging technique has been developed by labeling nanoparticles with single-photon emission computed tomography (SPECT) isotopes, the low temporal resolution of SPECT still limits its potential for visualizing the rapid dynamic process of renal clearable nanoparticles in vivo. The dynamic positron emission tomography (PET) imaging of renal clearable gold (Au) nanoparticles by labeling them with copper-64 ((64) Cu) to form (64) Cu-NOTA-Au-GSH is reported. Systematic nanoparticle synthesis and characterizations are performed to demonstrate the efficient renal clearance of as-prepared nanoparticles. A rapid renal clearance of (64) Cu-NOTA-Au-GSH is observed (>75%ID at 24 h post-injection) with its elimination half-life calculated to be less than 6 min, over 130 times shorter than previously reported similar nanoparticles. Dynamic PET imaging not only addresses the current challenges in accurately and non-invasively acquiring the organ kinetics, but also potentially provides a highly useful tool for studying renal clearance mechanism of other ultra-small nanoparticles, as well as the diagnosis of kidney diseases in the near future.

A systematic study of in vitro and in vivo behavior of biodegradable mesoporous silica nanoparticles (bMSNs), designed to carry multiple cargos (both small and macromolecular drugs) and subsequently self‐destruct following release of their payloads, is presented. Complete degradation of bMSNs is seen within 21 d of incubation in simulated body fluid. The as‐synthesized bMSNs are intrinsically radiolabeled with oxophilic zirconium‐89 (89Zr, t 1/2 = 78.4 h) radionuclide to track their in vivo pharmacokinetics via positron emission tomography imaging. Rapid and persistent CD105 specific tumor vasculature targeting is successfully demonstrated in murine model of metastatic breast cancer by using TRC105 (an anti‐CD105 antibody)‐conjugated bMSNs. This study serves to illustrate a simple, versatile, and readily tunable approach to potentially overcome the current challenges facing nanomedicine and further the goals of personalized nanotheranostics.

Multifunctional theranostic agents have become rather attractive to realize image-guided combination cancer therapy. Herein, we develop a novel method to synthesize Bi2Se3 nanosheets decorated with mono-dispersed FeSe2 nanoparticles (FeSe2/Bi2Se3) for tetra-modal image-guided combined photothermal & radiation tumor therapy. Interestingly, upon addition of Bi(NO3)3, pre-made FeSe2 nanoparticles via cation exchange would be gradually converted into Bi2Se3 nanosheets, on which remaining FeSe2 nanoparticles are decorated. The yielded FeSe2/Bi2Se3 composite-nanostructures were then modified with polyethylene glycol (PEG). Taking advantages of the high r2 relaxivity of FeSe2, the X-ray attenuation ability of Bi2Se3, the strong near-infrared (NIR) optical absorbance of the whole nanostructure, as well as the chelate-free radiolabeling of 64Cu on FeSe2/Bi2Se3-PEG, in vivo magnetic resonance (MR)/computer tomography (CT)/photoacoustic (PA)/position emission tomography (PET) multimodal imaging was carried out, revealing efficient tumor homing of FeSe2/Bi2Se3-PEG after intravenous injection. Utilizing the intrinsic physical properties of FeSe2/Bi2Se3-PEG, in vivo photothermal & radiation therapy to achieve synergistic tumor destruction was then realized, without causing obvious toxicity to the treated animals. Our work presents a unique method to synthesize composite-nanostructures with highly integrated functionalities, promising not only for nano-biomedicine, but also potentially for other different nanotechnology fields.

Layered double hydroxide (LDH) nanomaterial has emerged as a novel delivery agent for biomedical applications due to its unique structure and properties. However, in vivo positron emission tomography (PET) imaging with LDH nanoparticles has not been achieved. The aim of this study is to explore chelator-free labeling of LDH nanoparticles with radioisotopes for in vivo PET imaging. Bivalent cation 64Cu2+ and trivalent cation 44Sc3+ were found to readily label LDH nanoparticles with excellent labeling efficiency and stability, whereas tetravalent cation 89Zr4+ could not label LDH since it does not fit into the LDH crystal structure. PET imaging shows that prominent tumor uptake was achieved in 4T1 breast cancer with 64Cu-LDH-BSA via passive targeting alone (7.7 ± 0.1%ID/g at 16 h post-injection; n = 3). These results support that LDH is a versatile platform that can be labeled with various bivalent and trivalent radiometals without comprising the native properties, highly desirable for PET image-guided drug delivery.

Here we report the development of a family of nanoparticles that can withstand the harsh conditions of the stomach and intestine, avoid systemic absorption, and provide good optical contrast for photoacoustic imaging. The hydrophobicity of naphthalocyanine dyes was exploited to generate frozen micelles (nanonaps), with tunable near-infrared absorption. Nanonaps, following oral administration in mice, passed safely through the gastrointestinal tract. Non-invasive, non-ionizing photoacoustic techniques were used to visualize nanonap intestinal distribution with low background and remarkable resolution, and enabled real-time intestinal functional imaging with ultrasound co-registration.