Magnetic nanoparticles: multifunctional tool for cancer therapy

INTRODUCTION

Cancer has one of the highest mortality rates globally. The traditional therapies used to treat cancer have harmful adverse effects. Considering these facts, researchers have explored new therapeutic possibilities with enhanced benefits. Nanoparticle development for cancer detection, in addition to therapy, has shown substantial progress over the past few years.

AREA COVERED

Herein, the latest research regarding cancer treatment employing magnetic nanoparticles (MNPs) in chemo-, immuno-, gene-, and radiotherapy along with hyperthermia is summarized, in addition to their physio-chemical features, advantages, and limitations for clinical translation have also been discussed.

EXPERT OPINION

MNPs are being extensively investigated and developed into effective modules for cancer therapy. They are highly functional tools aimed at cancer therapy owing to their excellent superparamagnetic, chemical, biocompatible, physical, and biodegradable properties.

In Vitro Analysis of Superparamagnetic Iron Oxide Nanoparticles Coated with APTES as Possible Radiosensitizers for HNSCC Cells

Superparamagnetic iron oxide nanoparticles (SPION) are being investigated for many purposes, e.g., for the amplification of ionizing radiation and for the targeted application of therapeutics. Therefore, we investigated SPIONs coated with (3-Aminopropyle)-Triethoxysilane (SPION-APTES) for their influence on different head and neck squamous cell carcinoma (HNSCC) cell lines, as well as for their suitability as a radiosensitizer. We used 24-well microscopy and immunofluorescence microscopy for cell observation, growth curves to determine cytostatic effects, and colony formation assays to determine cytotoxicity. We found that the APTES-SPIONs were very well taken up by the HNSCC cells. They generally have a low cytotoxic effect, showing no significant difference in clonogenic survival between the control group and cells treated with 20 µg Fe/mL (p > 0.25) for all cell lines. They have a cytostatic effect on some cell lines cells (e.g., Cal33) that is visible across different radiation doses (1, 2, 8 Gy, p = 0.05). In Cal33, e.g., SPION-APTES raised the doubling time at 2 Gy from 24.53 h to 41.64 h. Importantly, these findings vary notably between the cell lines. However, they do not significantly alter the radiation effect: only one out of eight cell lines treated with SPION-APTES showed a significantly reduced clonogenic survival after ionizing radiation with 2 Gy, and only two showed significantly reduced doubling times. Thus, although the APTES-SPIONs do not qualify as a radiosensitizer, we were still able to vividly demonstrate and analyze the effect that the APTES-SPIONs have on various cell lines as a contribution to further functionalization.

Recent advances in engineering iron oxide nanoparticles for effective magnetic resonance imaging

Iron oxide nanoparticle (IONP) with unique magnetic property and high biocompatibility have been widely used as magnetic resonance imaging (MRI) contrast agent (CA) for long time. However, a review which comprehensively summarizes the recent development of IONP as traditional T₂ CA and its new application for different modality of MRI, such as T₁ imaging, simultaneous T₂/T₁ or MRI/other imaging modality, and as environment responsive CA is rare. This review starts with an investigation of direction on the development of high-performance MRI CA in both T₂ and T₁ modal based on quantum mechanical outer sphere and Solomon–Bloembergen–Morgan (SBM) theory. Recent rational attempts to increase the MRI contrast of IONP by adjusting the key parameters, including magnetization, size, effective radius, inhomogeneity of surrounding generated magnetic field, crystal phase, coordination number of water, electronic relaxation time, and surface modification are summarized. Besides the strategies to improve r₂ or r₁ values, strategies to increase the in vivo contrast efficiency of IONP have been reviewed from three different aspects, those are introducing second imaging modality to increase the imaging accuracy, endowing IONP with environment response capacity to elevate the signal difference between lesion and normal tissue, and optimizing the interface structure to improve the accumulation amount of IONP in lesion. This detailed review provides a deep understanding of recent researches on the development of high-performance IONP based MRI CAs. It is hoped to trigger deep thinking for design of next generation MRI CAs for early and accurate diagnosis.

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T₂ contrast capacity of iron oxide nanoparticles (IONPs) could be improved based on quantum mechanical outer sphere theory.

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IONPs could be expand to be used as effective T₁ CAs by improving q value, extending τ_s, and optimizing interface structure.

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Environment responsive MRI CAs have been developed to improve the diagnosis accuracy.

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Introducing other imaging contrast moiety into IONPs could increase the contrast efficiency.

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Optimizing in vivo behavior of IONPs have been proved to enlarge the signal difference between normal tissue and lesion.

A possible theranostic approach of chitosan-coated iron oxide nanoparticles against human colorectal carcinoma (HCT-116) cell line

Iron oxides have become increasingly popular for their use as a diagnostic and therapeutic tool in oncology. This study aimed to improve pharmacological valuable of Fe₃O₄, which may be use to diagnosis colorectal cancers (CRC). Here, we have developed chitosan (CS) coated Fe₃O₄ through a cost-effective procedure. First, we determined the characterization of OA-C-Fe₃O₄ by FTIR, UV–Vis spectra, and TEM. Then, we evaluated the photodynamic therapeutic (PDT) activity of OA-C-Fe₃O₄ in human colorectal carcinoma cell lines (HCT 116). Current results revealed that the light-induced enhanced reactive oxygen species (ROS) activity of the nanoparticles (NPs) and caused cell death via the activity of caspase 9/3. The in vitro magnetic resonance imaging (MRI) experiments in (HCT 116) and human embryonic kidney cells (HEK 293) illustrated that nanohybrid is an effective MRI contrasting agents for the diagnosis of colorectal cancer.

An Anti-inflammatory Fe3 O4 -Porphyrin Nanohybrid Capable of Apoptosis through Upregulation of p21 Kinase Inhibitor Having Immunoprotective Properties under Anticancer PDT Conditions

We report the influence of Fe₃ O₄ nanoparticles (NPs) on porphyrins in the development of photosensitizers (PSs) for efficient photodynamic therapy (PDT) and possible post-PDT responses for inflicting cancer cell death. Except for Au, most metal-based nanomaterials are unsuitable for clinical applications. The US Food and Drug Administration and other agencies have approved Feraheme and a few other iron oxide NPs for clinical use, paving the way for novel biocompatible immunoprotective superparamagnetic iron oxide nanohybrids to be developed as nanotherapeutics. A water-soluble nanohybrid, referred to here as E-NP, comprising superparamagnetic Fe₃ O₄ NPs functionalised with tripyridyl porphyrin PS was introduced through a rigid 4-carboxyphenyl linker. As a PDT agent, the efficacy of E-NP toward the AGS cancer cell line showed enhanced photosensitising ability as determined through in vitro photobiological assays. The cellular uptake of E-NPs by AGS cells led to apoptosis by upregulating ROS through cell-cycle arrest and loss of mitochondrial membrane potential. The subcellular localisation of the PSs in mitochondria stimulated apoptosis through upregulation of p21, a proliferation inhibitor capable of preventing tumour development. Under both PDT and non-PDT conditions, this nanohybrid can act as an anti-inflammatory agent by decreasing the production of NO and superoxide ions in murine macrophages, thus minimising collateral damage to healthy cells.

Progress of Cancer Nanotechnology as Diagnostics, Therapeutics, and Theranostics Nanomedicine: Preclinical Promise and Translational Challenges

Early detection, right therapeutic intervention, and simultaneous effectiveness mapping are considered the critical factors in successful cancer therapy. Nevertheless, these factors experience the limitations of conventional cancer diagnostics and therapeutics delivery approaches. Along with providing the targeted therapeutics delivery, advances in nanomedicines have allowed the combination of therapy and diagnostics in a single system (called cancer theranostics). This paper discusses the progress in the pre-clinical and clinical development of therapeutics, diagnostics, and theranostics cancer nanomedicines. It has been well evident that compared to the overabundance of works that claimed success in pre-clinical studies, merely 15 and around 75 cancer nanomedicines are approved, and currently under clinical trials, respectively. Thus, we also brief the critical bottlenecks in the successful clinical translation of cancer nanomedicines.

Microfluidic Synthesis of Iron Oxide Nanoparticles

Research efforts into the production and application of iron oxide nanoparticles (IONPs) in recent decades have shown IONPs to be promising for a range of biomedical applications. Many synthesis techniques have been developed to produce high-quality IONPs that are safe for in vivo environments while also being able to perform useful biological functions. Among them, coprecipitation is the most commonly used method but has several limitations such as polydisperse IONPs, long synthesis times, and batch-to-batch variations. Recent efforts at addressing these limitations have led to the development of microfluidic devices that can make IONPs of much-improved quality. Here, we review recent advances in the development of microfluidic devices for the synthesis of IONPs by coprecipitation. We discuss the main architectures used in microfluidic device design and highlight the most prominent manufacturing methods and materials used to construct these microfluidic devices. Finally, we discuss the benefits that microfluidics can offer to the coprecipitation synthesis process including the ability to better control various synthesis parameters and produce IONPs with high production rates.

Conjugated Photosensitizers for Imaging and PDT in Cancer Research

Early cancer detection and perfect understanding of the disease are imperative toward efficient treatments. It is straightforward that, for choosing a specific cancer treatment methodology, diagnostic agents undertake a critical role. Imaging is an extremely intriguing tool since it assumes a follow up to treatments to survey the accomplishment of the treatment and to recognize any conceivable repeating injuries. It also permits analysis of the disease, as well as to pursue treatment and monitor the possible changes that happen on the tumor. Likewise, it allows screening the adequacy of treatment and visualizing the state of the tumor. Additionally, when the treatment is finished, observing the patient is imperative to evaluate the treatment methodology and adjust the treatment if necessary. The goal of this review is to present an overview of conjugated photosensitizers for imaging and therapy.

Methylene blue-covered superparamagnetic iron oxide nanoparticles combined with red light as a novel platform to fight non-local bacterial infections: A proof of concept study against Escherichia coli

Currently, antimicrobial photodynamic therapy (APDT) is limited to the local treatment of topical infections, and a platform that can deliver the photosensitizer to internal organs is highly desirable for non-local ones; SPIONs can be promising vehicles for the photosensitizer. This work reports an innovative application of methylene blue (MB)-superparamagnetic iron oxide nanoparticles (SPIONs). We report on the preparation, characterization, and application of MB-SPIONs for antimicrobial photodynamic therapy. When exposed to light, the MB photosensitizer generates reactive oxygen species (ROS), which cause irreversible damage in microbial cells. We prepare SPIONs by the co-precipitation method. We cover the nanoparticles with a double silica layer - tetraethyl orthosilicate and sodium silicate - leading to the hybrid material magnetite-silica-MB. We characterize the as-prepared SPIONs by Fourier transform infrared spectroscopy, powder X-ray diffraction, and magnetic measurements. We confirm the formation of magnetite using powder X-ray diffraction data. We use the Rietveld method to calculate the average crystallite size of magnetite as being 14 nm. Infrared spectra show characteristic bands of iron‑oxygen as well as others associated with silicate groups. At room temperature, the nanocomposites present magnetic behavior due to the magnetite core. Besides, magnetite-silica-MB can promote ROS formation. Thus, we evaluate the photodynamic activity of Fe₃O₄-silica-MB on Escherichia coli. Our results show the bacteria are completely eradicated following photodynamic treatment depending on the MB release time from SPIONs and energy dose. These findings encourage us to explore the use of magnetite-silica-MB to fight internal infections in preclinical assays.

Magnetic Nanoparticles in Cancer Therapy and Diagnosis

There is urgency for the development of nanomaterials that can meet emerging biomedical needs. Magnetic nanoparticles (MNPs) offer high magnetic moments and surface-area-to-volume ratios that make them attractive for hyperthermia therapy of cancer and targeted drug delivery. Additionally, they can function as contrast agents for magnetic resonance imaging (MRI) and can improve the sensitivity of biosensors and diagnostic tools. Recent advancements in nanotechnology have resulted in the realization of the next generation of MNPs suitable for these and other biomedical applications. This review discusses methods utilized for the fabrication and engineering of MNPs. Recent progress in the use of MNPs for hyperthermia therapy, controlling drug release, MRI, and biosensing is also critically reviewed. Finally, challenges in the field and potential opportunities for the use of MNPs toward improving their properties are discussed.

Recent Advancements of Magnetic Nanomaterials in Cancer Therapy

Magnetic nanomaterials belong to a class of highly-functionalizable tools for cancer therapy owing to their intrinsic magnetic properties and multifunctional design that provides a multimodal theranostics platform for cancer diagnosis, monitoring, and therapy. In this review article, we have provided an overview of the various applications of magnetic nanomaterials and recent advances in the development of these nanomaterials as cancer therapeutics. Moreover, the cancer targeting, potential toxicity, and degradability of these nanomaterials has been briefly addressed. Finally, the challenges for clinical translation and the future scope of magnetic nanoparticles in cancer therapy are discussed.

Effects of polymer-coated boron nitrides with increased hemorheological compatibility on human erythrocytes and blood coagulation

BACKGROUND

Boron nitride (BN) nanomaterials are promising in biomedical research owing to their large surface area, graphene-like structure, and chemical and thermal properties. However, the toxicological effects of BN on erythrocytes and blood coagulation remain uninvestigated.

OBJECTIVE

The aims of our study were to synthesize glycol chitosan (GC)- and hyaluronic acid (HA)-coated BNs, and to investigate the effects of these BNs on human cancer cells, erythrocytes, and whole blood.

METHODS

We prepared hemocompatible forms of BN coated with GC and HA, and evaluated them using cell uptake/viability tests, hemolysis analysis and FE-SEM, as well as through hemorheological evaluation methods such as RBC deformability and aggregation, and blood coagulation.

RESULTS

GC/BN and HA/BN were both ∼200 nm, were successfully taken into cells, and emitted blue fluorescence. Both BNs were less toxic than bare BN, even at higher concentrations. The aggregation index of human red blood cells (RBCs) after 2 h incubation with BN, GC/BN, and HA/BN was greatly influenced, whereas RBC deformability did not dramatically change.

CONCLUSIONS

We found that GC/BN affected the intrinsic coagulation pathway, whereas both GC/BN and HA/BN affected the extrinsic pathway. Therefore, HA/BN is less detrimental to RBCs and blood coagulation dynamics than bare BN and GC/BN.

Therapeutic applications of iron oxide based nanoparticles in cancer: basic concepts and recent advances

Nanotechnology has introduced new techniques and phototherapy approaches to fabricate and utilize nanoparticles for cancer therapy. These phototherapy approaches, such as photothermal therapy (PTT) and photodynamic therapy (PDT), hold great promise to overcome the limitations of traditional treatment methods. In phototherapy, magnetic iron oxide nanoparticles (IONPs) are of paramount importance due to their wide range of biomedical applications. This review discusses the basic concepts, various therapy approaches (PTT, PDT, magnetic hyperthermia therapy (MHT), chemotherapy and immunotherapy), intrinsic properties, and mechanisms of cell death of IONPs; it also provides a brief overview of recent developments in IONPs, with focus on their therapeutic applications. Much attention is devoted to elaborating the various parameters, intracellular behaviors and limitations of MHT. Bimodal therapies which act alone or in combination with other modalities are also discussed. The review highlights some limitations in the explored research areas and suggests future directions to overcome these limitations.

In vivo multimodal tumor imaging and photodynamic therapy with novel theranostic agents based on the porphyrazine framework-chelated gadolinium (III) cation

BACKGROUND

A promising strategy for cancer diagnosis and therapy is the development of an agent for multimodal imaging and treatment. In the present paper we report on two novel multifunctional agents prepared on the porphyrazine pigment platform using a gadolinium (III) cation chelated by red-fluorescent tetrapyrrole macrocycles (GdPz1 and GdPz2).

METHODS

Spectral and magnetic properties of the compounds were analyzed. Monitoring of GdPz1 and GdPz2 accumulation in the murine colon carcinoma CT26 was performed in vivo using fluorescence imaging and MRI. The photobleaching of GdPz1 or GdPz2 and tumor growth rate after photodynamic therapy (PDT) were assessed.

RESULTS

GdPz1 and GdPz2 demonstrated the selective accumulation in tumor that was indicated by higher fluorescence intensity in the tumor area in comparison with the normal tissues. The results of MRI in vivo showed that GdPz1 or GdPz2 provided significant contrast enhancement of the tumor in T1 MR images. PDT with GdPz2 resulted in ~20% decrease in fluorescence intensity of the compound and the inhibition of tumor growth.

CONCLUSIONS

We assessed the efficiency of two innovative Gd(III) cation-porphyrazine chelates as bimodal MR and fluorescent probes and photosensitizers for PDT and showed their potentials for tumor diagnostics and treatment.

GENERAL SIGNIFICANCE

Water-soluble structures simple in preparation and administration into the body represent special interest for theranostics of tumors. Novel porphyrazine macrocycles chelating a central gadolinium cation demonstrated a good prospect as effective multimodal agents, representing a new approach to MRI and fluorescence imaging guided PDT.

Triple-functional albumin-based nanoparticles for combined chemotherapy and photodynamic therapy of pancreatic cancer with lymphatic metastases

Lymphatic metastasis is the major metastatic pattern of pancreatic cancer and considered as an independent risk factor of survival. However, there is still no effective way for the diagnosis and treatment for lymphatic metastases of pancreatic cancer. In this study, using albumin as a carrier of gemcitabine (Gem), further modified by pyropheophorbide-a, we have designed and synthesized a nanoparticle (NP) compound named "pheophorbide-a (P@)-Gem-human serum albumin (HSA)-NPs". By utilization of its tracer ability of lymphatic metastases, which is triggered by near-infrared irradiation and its visible dying ability, the compound is used for drug delivery tracking, meanwhile as a treating drug, as well as the combined effect of photodynamic therapy and chemotherapy. By the nude mice model of lymphatic metastases of pancreatic cancer (BxPC-3-LN7), we aim to explore the feasibility, effectiveness, and biological safety of diagnosis and treatment for the lymphatic metastases of pancreatic cancer by P@-Gem-HSA-NP, thereby, providing new methods and strategies for the study of nanodrug carrier and research on lymphatic metastases of pancreatic cancer.

Eradication of Plasmodium falciparum from Erythrocytes by Controlled Reactive Oxygen Species via Photodynamic Inactivation Coupled with Photofunctional Nanoparticles

We investigated the antimalarial effect of photodynamic inactivation (PDI) coupled with magnetic nanoparticles (MNPs) as a potential strategy to combat the emergence of drug-resistant malaria and resurgence of malaria after treatment. Because the malarial parasite proliferates within erythrocytes, PDI agents need to be taken up by erythrocytes to eradicate the parasite. We used photofunctional MNPs as the PDI agent because nanosized particles were selectively taken up by Plasmodium-infected erythrocytes and remained within the intracellular space due to the enhanced permeability and retention effect. Also, the magnetism of Fe₃O₄ nanoparticles can easily be utilized for the collection of photofunctional nanoparticles (PFNs), and the uptaken PFNs infected the erythrocytes after photodynamic treatment with external magnetics. Photofunctionality was provided by a photosensitizer, namely, pheophorbide A, which generates reactive oxygen species (ROS) under irradiation. PAs were covalently bonded to the surface of the MNPs. The morphology and structural characteristics of the MNPs were investigated by scanning electron microscopy and X-ray diffraction (XRD), whereas the photophysical properties of the PFNs were studied with Fourier transform infrared, absorption, and emission spectroscopies. Generation of singlet oxygen, a major ROS, was directly confirmed with time-resolved phosphorescence spectroscopy. To evaluate the ability of PFNs to kill malarial parasites, the PDI effect of PFNs was evaluated within the infected erythrocytes. Furthermore, malarial parasites were completely eradicated from the erythrocytes after PDI treatment using PFNs on the basis of an 8 day erythrocyte culture test.

Multifunctional nanoparticle composites: progress in the use of soft and hard nanoparticles for drug delivery and imaging

With continued advancements in nanoparticle (NP) synthesis and in the interfacing of NPs with biological systems has come the exponential growth in the use of NPs for therapeutic drug delivery and imaging applications. In recent years, the advent of NP multifunctionality-the ability to perform multiple, disparate functions on a single NP platform-has garnered much excitement for the potential realization of highly functional NP-mediated drug delivery for use in the clinical setting. This Overview will survey the current state of the art (reports published within the last 5 years) of multifunctional NPs for therapeutic drug delivery, imaging or a combination thereof. We provide extensive examples of both soft (micelles, liposomes, polymeric NPs) and hard (noble metals, quantum dots, metal oxides) NP formulations that have been used for multimodal drug delivery and imaging. The criteria for inclusion, herein, is that there must be at least two therapeutic drug cargos or imaging agents or a combination of the two. We next offer an assessment of the cytotoxicity of therapeutic NP constructs in biological systems. We then conclude with a forward-looking perspective on how we expect this field to develop in the coming years. WIREs Nanomed Nanobiotechnol 2017, 9:e1466. doi: 10.1002/wnan.1466 For further resources related to this article, please visit the WIREs website.

Tissue Plasminogen Activator Binding to Superparamagnetic Iron Oxide Nanoparticle-Covalent Versus Adsorptive Approach

Functionalized superparamagnetic iron oxide nanoparticles are frequently used to develop vehicles for drug delivery, hyperthermia, and photodynamic therapy and as tools used for magnetic separation and purification of proteins or for biomolecular imaging. Depending on the application, there are various possible covalent and non-covalent approaches for the functionalization of particles, each of them shows different advantages and disadvantages for drug release and activity at the desired location.Particularly important for the production of adsorptive and covalent bound drugs to nanoparticles is the pureness of the involved formulation. Especially the covalent binding strategy demands defined chemistry of the drug, which is stabilized by excess free amino acids which could reduce reaction efficiency. In this study, we therefore used tangential flow filtration (TFF) method to purify the drugs before the reaction and used the frequently applied and clinically available recombinant tissue plasminogen activator (tPA; Actilyse(®)) as a proof of concept. We then coupled the tPA preparation to polyacrylic acid-co-maleic acid (PAM)-coated superparamagnetic iron oxide nanoparticles (SPIONs) using an amino-reactive activated ester reaction and compared these particles to PAM-coated SPIONs with electrostatically adsorbed tPA.Using dynamic light scattering (DLS) and pH-dependent electrokinetic mobility measurements, we showed that surface properties of the SPIONs were significantly greater affected after activation of the particles compared to the adsorption controls. Different in vitro assays were used to investigate the activity of tPA after coupling to the particles and purification of the ferrofluid. Covalent linkage significantly improves the reactivity and long-term stability of the conjugated SPION-tPA system compared to simple adsorption. In conclusion, we have shown an effective way to produce SPIONs with covalent and non-covalent ultra-filtrated drugs. We showed that using activated ester reaction, immobilization of the protein was significantly better than in adsorptive approaches. Investigation of those functionalized SPIONs revealed diverging attributes, which should be taken into account when developing nanoparticles for different applications.

Magnetic Nanoparticle Facilitated Drug Delivery for Cancer Therapy with Targeted and Image-Guided Approaches

With rapid advances in nanomedicine, magnetic nanoparticles (MNPs) have emerged as a promising theranostic tool in biomedical applications, including diagnostic imaging, drug delivery and novel therapeutics. Significant preclinical and clinical research has explored their functionalization, targeted delivery, controllable drug release and image-guided capabilities. To further develop MNPs for theranostic applications and clinical translation in the future, we attempt to provide an overview of the recent advances in the development and application of MNPs for drug delivery, specifically focusing on the topics concerning the importance of biomarker targeting for personalized therapy and the unique magnetic and contrast-enhancing properties of theranostic MNPs that enable image-guided delivery. The common strategies and considerations to produce theranostic MNPs and incorporate payload drugs into MNP carriers are described. The notable examples are presented to demonstrate the advantages of MNPs in specific targeting and delivering under image guidance. Furthermore, current understanding of delivery mechanisms and challenges to achieve efficient therapeutic efficacy or diagnostic capability using MNP-based nanomedicine are discussed.

Magnetite nanoparticles for cancer diagnosis, treatment, and treatment monitoring: recent advances

The development of nanoparticles (NPs) for use in all facets of oncological disease detection and therapy has shown great progress over the past two decades. NPs have been tailored for use as contrast enhancement agents for imaging, drug delivery vehicles, and most recently as a therapeutic component in initiating tumor cell death in magnetic and photonic ablation therapies. Of the many possible core constituents of NPs, such as gold, silver, carbon nanotubes, fullerenes, manganese oxide, lipids, micelles, etc., iron oxide (or magnetite) based NPs have been extensively investigated due to their excellent superparamagnetic, biocompatible, and biodegradable properties. This review addresses recent applications of magnetite NPs in diagnosis, treatment, and treatment monitoring of cancer. Finally, some views will be discussed concerning the toxicity and clinical translation of iron oxide NPs and the future outlook of NP development to facilitate multiple therapies in a single formulation for cancer theranostics.

Ternary graphene quantum dot-polydopamine-Mn3O4 nanoparticles for optical imaging guided photodynamic therapy and T1-weighted magnetic resonance imaging

Imaging-guided therapy, which bridges treatment and diagnosis, plays an important role in overcoming the limitations of classical cancer therapy. To provide a more exact location of the tumor and to reduce side effects to normal tissues, a multifunctional probe was designed to serve as both an imaging agent and a therapeutic agent. Ternary hybrid nanoparticles comprised of visible red-responsive graphene, the T1-weighted magnetic resonance imaging (MRI) agent Mn3O4 and a mussel-inspired linker polydopamine. The conjugation of graphene to Mn3O4 through polydopamine enhanced the water solubility of Mn3O4, enabling an efficient uptake by cancer cells as well as tumor accumulation when the nanoparticles were intravenously administered into mice. These nanoparticles, when localized at a tumor site, exhibited low cytotoxicity in the dark, while light irradiation of the cancer cells transfected with the nanoparticles resulted in significant phototherapeutic effects, apparently by generating toxic reactive oxygen species. These nanoparticles also allowed excellent T1-weighted MR imaging in a human lung cancer xenograft model and were successfully used for combined visible red-imaging-guided photodynamic therapy and T1-weighted MRI.