Noninvasive Dynamic Imaging of Tumor Early Response to Nanoparticle-mediated Photothermal Therapy

Treating Alzheimer's disease using nanoparticle-mediated drug delivery strategies/systems

The administration of promising medications for the treatment of neurodegenerative disorders (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) is significantly hampered by the blood-brain barrier (BBB). Nanotechnology has recently come to light as a viable strategy for overcoming this obstacle and improving drug delivery to the brain. With a focus on current developments and prospects, this review article examines the use of nanoparticles to overcome the BBB constraints to improve drug therapy for AD The potential for several nanoparticle-based approaches, such as those utilizing lipid-based, polymeric, and inorganic nanoparticles, to enhance drug transport across the BBB are highlighted. To shed insight on their involvement in aiding effective drug transport to the brain, methods of nanoparticle-mediated drug delivery, such as surface modifications, functionalization, and particular targeting ligands, are also investigated. The article also discusses the most recent findings on innovative medication formulations encapsulated within nanoparticles and the therapeutic effects they have shown in both preclinical and clinical testing. This sector has difficulties and restrictions, such as the need for increased safety, scalability, and translation to clinical applications. However, the major emphasis of this review aims to provide insight and contribute to the knowledge of how nanotechnology can potentially revolutionize the worldwide treatment of NDDs, particularly AD, to enhance clinical outcomes.

Joining Forces: The Combined Application of Therapeutic Viruses and Nanomaterials in Cancer Therapy

Cancer, on a global scale, presents a monumental challenge to our healthcare systems, posing a significant threat to human health. Despite the considerable progress we have made in the diagnosis and treatment of cancer, realizing precision cancer therapy, reducing side effects, and enhancing efficacy remain daunting tasks. Fortunately, the emergence of therapeutic viruses and nanomaterials provides new possibilities for tackling these issues. Therapeutic viruses possess the ability to accurately locate and attack tumor cells, while nanomaterials serve as efficient drug carriers, delivering medication precisely to tumor tissues. The synergy of these two elements has led to a novel approach to cancer treatment-the combination of therapeutic viruses and nanomaterials. This advantageous combination has overcome the limitations associated with the side effects of oncolytic viruses and the insufficient tumoricidal capacity of nanomedicines, enabling the oncolytic viruses to more effectively breach the tumor's immune barrier. It focuses on the lesion site and even allows for real-time monitoring of the distribution of therapeutic viruses and drug release, achieving a synergistic effect. This article comprehensively explores the application of therapeutic viruses and nanomaterials in tumor treatment, dissecting their working mechanisms, and integrating the latest scientific advancements to predict future development trends. This approach, which combines viral therapy with the application of nanomaterials, represents an innovative and more effective treatment strategy, offering new perspectives in the field of tumor therapy.

A novel combination for the treatment of small cell lung cancer: Active targeted irinotecan and stattic co-loaded PLGA nanoparticles

Polymeric nanoparticles are widely used drug delivery systems for cancer treatment due to their properties such as ease of passing through biological membranes, opportunity to modify drug release, specifically targeting drugs to diseased areas, and potential of reducing side effects. Here, we formulated irinotecan and Stattic co-loaded PLGA nanoparticles targeted to small cell lung cancer. Nanoparticles were successfully conjugated with CD56 antibody with a conjugation efficiency of 84.39 ± 1.01%, and characterization of formulated nanoparticles was conducted with in-vitro and in-vivo studies. Formulated particles had sizes in the range of 130-180 nm with PDI values smaller than 0.3. Encapsulation and active targeting of irinotecan and Stattic resulted in increased cytotoxicity and anti-cancer efficiency in-vitro. Furthermore, it was shown with ex-vivo biodistribution studies that conjugated nanoparticles were successfully targeted to CD56-expressing SCLC cells and distributed mainly to tumor tissue and lungs. Compliant with our hypothesis and literature, the STAT3 pathway was successfully inhibited with Stattic solution and Stattic loaded nanoparticles. Additionally, intravenous injection of conjugated co-loaded nanoparticles resulted in decreased side effects and better anti-tumor activity than individual solutions of drugs in SCLC tumor-bearing mice. These results may indicate a new treatment option for clinically aggressive small cell lung cancer.

Platelets for cancer treatment and drug delivery

Extensive research is currently being conducted into a variety of bio-inspired biomimetic nanoparticles (NPs) with new cell simulation functions across the fields of materials science, chemistry, biology, physics, and engineering. Cells such as erythrocytes, platelets, and stem cells have been engineered as new drug carriers. The platelet-derived drug delivery system, which is a new targeted drug delivery system (TDDS), can effectively navigate the blood circulatory system and interact with the complex tumor microenvironment; it appears to outperform traditional anticancer drugs; hence, it has attracted considerable research interest. In this review, we describe innovative studies and outline the latest progress regarding the use of platelets as tumor targeting and drug delivery vehicles; we also highlight opportunities and challenges relevant to the manufacture of tumor-related platelet TDDSs.

Anisotropic Plasmonic Gold Nanorod-Indocyanine Green@Reduced Graphene Oxide-Doxorubicin Nanohybrids for Image-Guided Enhanced Tumor Theranostics

The unique physicochemical and localized surface plasmon resonance assets of gold nanorods (GNRs) have offered combined cancer treatments with real-time diagnosis by integrating diverse theragnostic modalities into a single nanoplatform. In this work, a unique multifunctional nanohybrid material based on GNRs was designed for in vitro and in vivo tumor imaging along with synergistic and combinatorial therapy of tumor. The hybrid material with size less than 100 nm was achieved by embedding indocyanine green (ICG) on mesoporous silica-coated GNRs with further wrapping of reduced graphene oxide (rGO) and then attached with doxorubicin (DOX) and polyethylene glycol. The nanohybrid unveiled noteworthy stability and competently protected the embedded ICG from further aggregation, photobleaching, and nucleophilic attack by encapsulation of GNRs-ICG with rGO. Such combination of GNRs-ICG with rGO and DOX served as a real-time near-infrared (NIR) contrast imaging agent for cancer diagnosis. The hybrid material exhibits high NIR absorption property along with three destined capabilities, such as, nanozymatic activity, photothermal activity, and an excellent drug carrier for drug delivery. The integrated properties of the nanohybrid were then utilized for the triple mode of combined therapeutics of tumor cells, through synergistic catalytic therapy and chemotherapy with combinatorial photothermal therapy to achieve the maximum cancer killing efficiency. It is assumed that the assimilated multimodal imaging and therapeutic capability in single nanoparticle platform is advantageous for future practical applications in cancer diagnosis, therapy, and molecular imaging.

Advanced Magnetic Resonance Imaging (MRI) Techniques: Technical Principles and Applications in Nanomedicine

Simple Summary

Magnetic Resonance Imaging (MRI) is a consolidated imaging tool for the multiparametric assessment of tissues in various pathologies from degenerative and inflammatory diseases to cancer. In recent years, the continuous technological evolution of the equipment has led to the development of sequences that provide not only anatomical but also functional and metabolic information. In addition, there is a growing and emerging field of research in clinical applications using MRI to exploit the diagnostic and therapeutic capabilities of nanocompounds. This review illustrates the application of the most advanced magnetic resonance techniques in the field of nanomedicine.

Abstract

In the last decades, nanotechnology has been used in a wide range of biomedical applications, both diagnostic and therapeutic. In this scenario, imaging techniques represent a fundamental tool to obtain information about the properties of nanoconstructs and their interactions with the biological environment in preclinical and clinical settings. This paper reviews the state of the art of the application of magnetic resonance imaging in the field of nanomedicine, as well as the use of nanoparticles as diagnostic and therapeutic tools, especially in cancer, including the characteristics that hinder the use of nanoparticles in clinical practice.

Nanoparticles as a Tool in Neuro-Oncology Theranostics

The rapid growth of nanotechnology and the development of novel nanomaterials with unique physicochemical characteristics provides potential for the utility of nanomaterials in theranostics, including neuroimaging, for identifying neurodegenerative changes or central nervous system malignancy. Here we present a systematic and thorough review of the current evidence pertaining to the imaging characteristics of various nanomaterials, their associated toxicity profiles, and mechanisms for enhancing tropism in an effort to demonstrate the utility of nanoparticles as an imaging tool in neuro-oncology. Particular attention is given to carbon-based and metal oxide nanoparticles and their theranostic utility in MRI, CT, photoacoustic imaging, PET imaging, fluorescent and NIR fluorescent imaging, and SPECT imaging.

18F-FDG positron emission tomography and diffusion-weighted magnetic resonance imaging for response evaluation of nanoparticle-mediated photothermal therapy

Nanoparticle-mediated photothermal cancer therapy (PTT) is a treatment which creates localized damage to tumors via nanoparticles that generate heat when irradiated with near infrared light. Substantial work has been dedicated to developing efficient heat-transducing nanoparticles that can be delivered systemically to the tumor. However, less attention has been given to clinically relevant assessment methods of treatment outcome that could be used for personalizing the therapy. Here, we compare ¹⁸F-FDG positron emission tomography combined with computed tomography (PET/CT) and diffusion-weighted imaging (DWI) for early evaluation and prognosis of PTT in tumor-bearing mice using silica-gold nanoshells (NS). The NS-treated mice experienced inhibited tumor growth and significantly prolonged survival compared to control mice. One day after PTT, PET/CT and DWI scans showed a decrease in tumor ¹⁸F-FDG uptake of ~90% and an increase of ~50% in apparent diffusion coefficient (ADC) values respectively, compared to baseline. No significant changes were observed for control groups. Additionally, the changes in ¹⁸F-FDG uptake and ADC values correlated significantly with survival, demonstrating that both methods can be used for early evaluation of PTT although ¹⁸F-FDG PET/CT showed the strongest prognostic value. Based on these results, both modalities should be considered for therapy monitoring of PTT when clinically translated.

Antibacterial Property of Composites of Reduced Graphene Oxide with Nano-Silver and Zinc Oxide Nanoparticles Synthesized Using a Microwave-Assisted Approach

Graphene oxide (GO) composites with various metal nanoparticles (NPs) are attracting increasing interest owing to their broad scope in biomedical applications. Here, microwave-assisted chemical reduction was used to deposit nano-silver and zinc oxide NPs (Ag and ZnO NPs) on the surface of reduced GO (rGO) at the following weight percentages: 5.34% Ag/rGO, 7.49% Ag/rGO, 6.85% ZnO/rGO, 16.45% ZnO/rGO, 3.47/34.91% Ag/ZnO/rGO, and 7.08/15.28% Ag/ZnO/rGO. These materials were tested for antibacterial activity, and 3.47/34.91% Ag/ZnO/rGO and 7.08/15.28% Ag/ZnO/rGO exhibited better antibacterial activity than the other tested materials against the gram-negative bacterium Escherichia coli K12. At 1000 ppm, both these Ag/ZnO/rGO composites had better killing properties against both E. coli K12 and the gram-positive bacterium Staphylococcus aureus SA113 than Ag/rGO and ZnO/rGO did. RedoxSensor flow cytometry showed that 3.47/34.91% Ag/ZnO/rGO and 7.08/15.28% Ag/ZnO/rGO decreased reductase activity and affected membrane integrity in the bacteria. At 100 ppm, these two composites affected membrane integrity more in E. coli, while 7.08/15.28% Ag/ZnO/rGO considerably decreased reductase activity in S. aureus. Thus, the 3.47/34.91% and 7.08%/15.28% Ag/ZnO/rGO nanocomposites can be applied not only as antibacterial agents but also in a variety of biomedical materials such as sensors, photothermal therapy, drug delivery, and catalysis, in the future.

Platelet-membrane-biomimetic nanoparticles for targeted antitumor drug delivery

BACKGROUND

Nanoscale drug-delivery systems (DDSs) have great promise in tumor diagnosis and treatment. Platelet membrane (PLTM) biomimetic DDSs are expected to enhance retention in vivo and escape uptake by macrophages, as well as minimizing immunogenicity, attributing to the CD47 protein in PLTM sends "don't eat me" signals to macrophages. In addition, P-selectin is overexpressed on the PLTM, which would allow a PLTM-biomimetic DDS to specifically bind to the CD44 receptors upregulated on the surface of cancer cells.

RESULTS

In this study, porous nanoparticles loaded with the anti-cancer drug bufalin (Bu) were prepared from a chitosan oligosaccharide (CS)-poly(lactic-co-glycolic acid) (PLGA) copolymer. These were subsequently coated with platelet membrane (PLTM) to form PLTM-CS-pPLGA/Bu NPs. The PLTM-CS-pPLGA/Bu NPs bear a particle size of ~ 192 nm, and present the same surface proteins as the PLTM. Confocal microscopy and flow cytometry results revealed a greater uptake of PLTM-CS-pPLGA/Bu NPs than uncoated CS-pPLGA/Bu NPs, as a result of the targeted binding of P-selectin on the surface of the PLTM to the CD44 receptors of H22 hepatoma cells. In vivo biodistribution studies in H22-tumor carrying mice revealed that the PLTM-CS-pPLGA NPs accumulated in the tumor, because of a combination of active targeting effect and the EPR effect. The PLTM-CS-pPLGA/Bu NPs led to more effective tumor growth inhibition over other bufalin formulations.

CONCLUSIONS

Platelet membrane biomimetic nanoparticles played a promising targeted treatment of cancer with low side effect.

Bridging the translational gap: Implementation of multimodal small animal imaging strategies for tumor burden assessment in a co-clinical trial

In designing co-clinical cancer studies, preclinical imaging brings unique challenges that emphasize the gap between man and mouse. Our group is developing quantitative imaging methods for the preclinical arm of a co-clinical trial studying immunotherapy and radiotherapy in a soft tissue sarcoma model. In line with treatment for patients enrolled in the clinical trial SU2C-SARC032, primary mouse sarcomas are imaged with multi-contrast micro-MRI (T1 weighted, T2 weighted, and T1 with contrast) before and after immune checkpoint inhibition and pre-operative radiation therapy. Similar to the patients, after surgery the mice will be screened for lung metastases with micro-CT using respiratory gating. A systems evaluation was undertaken to establish a quantitative baseline for both the MR and micro-CT systems against which others systems might be compared. We have constructed imaging protocols which provide clinically-relevant resolution and contrast in a genetically engineered mouse model of sarcoma. We have employed tools in 3D Slicer for semi-automated segmentation of both MR and micro-CT images to measure tumor volumes efficiently and reliably in a large number of animals. Assessment of tumor burden in the resulting images was precise, repeatable, and reproducible. Furthermore, we have implemented a publicly accessible platform for sharing imaging data collected during the study, as well as protocols, supporting information, and data analyses. In doing so, we aim to improve the clinical relevance of small animal imaging and begin establishing standards for preclinical imaging of tumors from the perspective of a co-clinical trial.

Black TiO2-based nanoprobes for T1-weighted MRI-guided photothermal therapy in CD133 high expressed pancreatic cancer stem-like cells

At present, transmembrane glycoprotein CD133 highly expressed pancreatic cancer stem cells (PCSCs), with the features of chemotherapeutic/radiotherapeutic resistance and exclusive tumorigenic potential, are considered as the primary cause of metastasis and recurrence in pancreatic cancer, and therefore are an effective target in the disease treatment. Furthermore, with the launch of precision medicine, multifunctional nanoprobes have been applied as an efficient strategy for the magnetic resonance imaging (MRI)-guided photothermal therapy (PTT) of pancreatic cancer. In this research, with the aim of achieving precise MRI-guided PTT in CD133 highly expressed PCSCs, novel bTiO2-Gd-CD133mAb nanoprobes were designed and successfully prepared by loading Gd-DOTA and CD133 monoclonal antibodies on black TiO2 nanoparticles. It was very interesting to find that the r1 relaxivity value of the nanoprobes was 34.394 mM-1 s-1, about 7.5 times that of commercial Magnevist (4.5624 mM-1 s-1), which indicates that the nanoprobes have good potential as MRI T1 contrast agents with excellent performance. Herein, CD133 highly expressed PANC-1 cells were selected and verified as PCSCs model. In vitro experiments demonstrated that the nanoprobes exhibited active-targeting ability in PANC-1 cells, and consequently could specially enhance T1-weighted MR imaging and 808 nm near-infrared (NIR)-triggered PTT efficiency in the PCSCs model. Our study not only provides a new strategy for the effective treatment of pancreatic cancer and its' stem cells, but also further broadens the application of black TiO2 in the field of cancer theranostics.

Non-invasive Early Response Monitoring of Nanoparticle-assisted Photothermal Cancer Therapy Using 18F-FDG, 18F-FLT, and 18F-FET PET/CT Imaging

Rationale: Since its first implementation nanoparticle-assisted photothermal cancer therapy has been studied extensively, although mainly with focus on optimal nanoparticle design. However, development of efficient treatment protocols, as well as reliable and early evaluation tools in vivo, are needed to push the therapy towards clinical translation. Positron emission tomography (PET) is a non-invasive imaging technique that is currently finding extensive use for early evaluation of cancer therapies; an approach that has become of increasing interest due to its great potential for personalized medicine.

Methods: In this study, we performed PET imaging to evaluate the treatment response two days after nanoparticle-assisted photothermal cancer therapy in tumor-bearing mice. We used three different tracers; 2′-deoxy-2′-¹⁸F-fluoro-D-glucose (¹⁸F-FDG), 3′-deoxy-3′-¹⁸F-fluorothymidine (¹⁸F-FLT), and O-(2'-¹⁸F-fluoroethyl)-L-tyrosine (¹⁸F-FET) to image and measure treatment induced changes in glucose uptake, cell proliferation, and amino acid transport, respectively. After therapy, tumor growth was monitored longitudinally until endpoint was reached.

Results: We found that nanoparticle-assisted photothermal therapy overall inhibited tumor growth and prolonged survival. All three PET tracers had a significant decrease in tumor uptake two days after therapy and these changes correlated with future tumor growth, with ¹⁸F-FDG having the most predictive value in this tumor model.

Conclusion: This study shows that ¹⁸F-FDG, ¹⁸F-FLT, and ¹⁸F-FET are all robust markers for the treatment response of photothermal therapy, and demonstrate that PET imaging can be used for stratification and optimization of the therapy. Furthermore, having a selection of PET tracers that can reliably measure treatment response is highly valuable as the individual tracer might be excluded in certain applications where physiological processes limit their contrast to background.

Noninvasive magnetic resonance/photoacoustic imaging for photothermal therapy response monitoring

In vivo assessment of vascular permeability and therapeutic response provides novel insights into photothermal therapy (PTT) that is currently under clinical investigation. We have developed noninvasive imaging strategies to improve the monitoring of nanoparticle-mediated PTT responses for personalized nanomedicine. Briefly, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and photoacoustic imaging (PAI) were applied to study the enhanced permeability and retention (EPR) effect in tumor models of different microvascular permeabilities (i.e., 4T1 mouse breast tumor model and HUH-7 human hepatoma model in nude mice). Magnetic resonance temperature imaging (MRTI) and diffusion-weighted MRI (DWI) showed that the 4T1 tumor model exhibits a higher PTT temperature response than that of the HUH-7 tumor model. Our findings demonstrate that the combined use of MRI and PAI techniques is useful in monitoring the vascular permeability and temperature status following PTT, promising to help guide PTT in future translational investigation.

Volumetric Optoacoustic Temperature Mapping in Photothermal Therapy

Photothermal therapy and ablation are commonplace medical procedures employed for treatment of tumors, vascular and brain abnormalities as well as other disorders that require selective destruction of tissues. Yet, accurate mapping of the dynamic temperature field distribution in the treated region represents an unmet clinical need, strongly affecting the clinical outcome of these interventions. We introduce a fast three-dimensional temperature mapping method based on real-time optoacoustic sensing of the treated region coupled with a thermal-diffusion-based model of heat distribution in tissues. Deviations of the optoacoustic temperature readings provided at 40  ms intervals remained below 10% in tissue-mimicking phantom experiments for temperature elevations above 3 °C, as validated by simultaneous thermocouple measurements. Performance of the new method to dynamically estimate the volumetric temperature distribution was further showcased in post-mortem mouse imaging experiments. The newly discovered capacity to non-invasively measure the temperature map in an entire treated volume with both high spatial and temporal resolutions holds potential for improving safety and efficacy of light-based therapeutic interventions.

A Novel Gd-DTPA-conjugated Poly(L-γ-glutamyl-glutamine)-paclitaxel Polymeric Delivery System for Tumor Theranostics

The conventional chemotherapeutics could not be traced in vivo and provide timely feedback on the clinical effectiveness of drugs. In this study, poly(L-γ-glutamyl-glutamine)-paclitaxel (PGG-PTX), as a model polymer, was chemically conjugated with Gd-DTPA (Gd-diethylenetriaminepentaacetic acid), a T₁-contrast agent of MRI, to prepare a Gd-DTPA-conjugated PGG-PTX (PGG-PTX-DTPA-Gd) delivery system used for tumor theranostics. PGG-PTX-DTPA-Gd can be self-assembled to NPs in water with a z-average hydrodynamic diameter about 35.9 nm. The 3 T MRI results confirmed that the relaxivity of PGG-PTX-DTPA-Gd NPs (r₁ = 18.98 mM⁻¹S⁻¹) was increased nearly 4.9 times compared with that of free Gd-DTPA (r₁ = 3.87 mM⁻¹S⁻¹). The in vivo fluorescence imaging results showed that PGG-PTX-DTPA-Gd NPs could be accumulated in the tumor tissue of NCI-H460 lung cancer animal model by EPR effect, which was similar to PGG-PTX NPs. The MRI results showed that compared with free Gd-DTPA, PGG-PTX-DTPA-Gd NPs showed significantly enhanced and prolonged signal intensity in tumor tissue, which should be attributed to the increased relaxivity and tumor accumulation. PGG-PTX-DTPA-Gd NPs also showed effective antitumor effect in vivo. These results indicated that PGG-PTX-DTPA-Gd NPs are an effective delivery system for tumor theranostics, and should have a potential value in personalized treatment of tumor.

18F-FDG PET/CT-based early treatment response evaluation of nanoparticle-assisted photothermal cancer therapy

Within the field of nanoparticle-assisted photothermal cancer therapy, focus has mostly been on developing novel heat-generating nanoparticles with the right optical and dimensional properties. Comparison and evaluation of their performance in tumor-bearing animals are commonly assessed by changes in tumor volume; however, this is usually a late-occurring event. This study implements 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography imaging to perform early evaluation of the treatment outcome of photothermal therapy. Silica-gold nanoshells (NS) are administered intravenously to nude mice bearing human neuroendocrine tumor xenografts and the tumors are irradiated by a near-infrared laser. The animals are positron emission tomography scanned with 2-deoxy-2-[F-18]fluoro-D-glucose one day before and one day after treatment. Using this setup, a significant decrease in tumor uptake of 2-deoxy-2-[F-18]fluoro-D-glucose is found already one day after therapy in the group receiving NS and laser treatment compared to control animals. At this time point no change in tumor volume can be detected. Moreover, the change in tumor uptake, is used to stratify the animals into responders and non-responders, where the responding group matched improved survival. Overall, these findings support the use of 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography imaging for preclinical and clinical evaluation and optimization of photothermal therapy.

Recent advances in different modal imaging-guided photothermal therapy

Photothermal therapy (PTT) has recently attracted considerable attention owing to its controllable treatment process, high tumour eradication efficiency and minimal side effects on non-cancer cells. PTT can melt cancerous cells by localising tissue hyperthermia induced by internalised therapeutic agents with a high photothermal conversion efficiency under external laser irradiation. Numerous in vitro and in vivo studies have shown the significant potential of PTT to treat tumours in future practical applications. Unfortunately, the lack of visualisation towards agent delivery and internalisation, as well as imaging-guided comprehensive evaluation of therapeutic outcome, limits its further application. Developments in combined photothermal therapeutic nanoplatforms guided by different imaging modalities have compensated for the major drawback of PTT alone, proving PTT to be a promising technique in biomedical applications. In this review, we introduce recent developments in different imaging modalities including single-modal, dual-modal, triple-modal and even multi-modal imaging-guided PTT, together with imaging-guided multi-functional theranostic nanoplatforms.

Monitoring of the tumor response to nano-graphene oxide-mediated photothermal/photodynamic therapy by diffusion-weighted and BOLD MRI

Photothermal therapy (PTT) and photodynamic therapy (PDT) are promising cancer treatment modalities. Because each modality has its own set of advantages and limitations, there has been interest in developing methods that can co-deliver the two regimens for enhanced tumor treatment. Among the efforts, nano-graphene oxide-mediated phototherapies have recently attracted much attention. Nano-graphene oxide has a broad absorbance spectrum and can be loaded with photosensitizers, such as chlorin e6, with high efficiency. Chlorin e6-loaded and PEGylated nano-graphene (GO-PEG-Ce6) can be excited at 660 nm, 808 nm, or both, to induce PDT, PTT, or PDT/PTT combination. Despite the potential of the treatments, there is a lack of a diagnostic tool which can monitor their therapeutic response in a non-invasive and prognostic manner; such an ability is urgently needed for the transformation and translation of the technologies. In this study, we performed diffusion-weighted and blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) after GO-PEG-Ce6-mediated PTT, PDT, or PTT/PDT. We found that after efficient PTT, there is a significant increase of the tumor apparent diffusion coefficient (ADC) value in diffusion-weighted imaging (DWI) maps; meanwhile, an efficient PDT led to an increase of in BOLD images. In both the cases, the amplitude of the increase was correlated with the treatment outcomes. More interestingly, a synergistic treatment efficacy was observed when the PTT/PDT combination was applied, and the combination was associated with a greater ADC and increase than when either modality was used alone. In particular, the PTT/PDT condition that induced the most dramatic short-term increase of the ADC value (>70%) caused the most effective tumor control in the long-run, with 60% of the treated animals being tumor-free after 60 days. These results suggest the great promise of the combination of DWI and BOLD MRI as a tool for accurate monitoring and prognosis of phototherapies, which is of great value to the future developments of the methodologies.

A dendronized heparin–gadolinium polymer self-assembled into a nanoscale system as a potential magnetic resonance imaging contrast agent

An amphiphilic dendronized heparin–gadolinium conjugate self-assembles into a nanoscale system by a combination of the features of the nanoparticle, dendrimer and heparin. The nanoscale system demonstrates great potential as an efficient and safe MRI contrast agent.