Photosensitizer-conjugated magnetic nanoparticles for in vivo simultaneous magnetofluorescent imaging and targeting therapy

Magnetic iron oxide modified pyropheophorbide-a fluorescence nanoparticles as photosensitizers for photodynamic therapy against ovarian cancer (SKOV-3) cells

Magnetic iron oxide modified pyropheophorbide-a fluorescence nanoparticles for photodynamic therapy against SKOV-3 cells.

Preparation, characterization and in vitro photodynamic therapy of a pyropheophorbide-a-conjugated Fe3O4 multifunctional magnetofluorescence photosensitizer

Core–shell structure magneto-fluorescence chlorin pyropheorbide-a photosensitizer (MFNPs) with good water-dispersity and strong superparamagnetic for photodynamic therapy.

The study on the preparation and characterization of gene-loaded immunomagnetic albumin nanospheres and their anti-cell proliferative effect combined with magnetic fluid hyperthermia on GLC-82 cells

As one of the most common malignant tumors, the clinical and socio-economic consequences of lung cancer are significant. Currently, surgery is the main treatment strategy for this disease, but the survival rates of lung cancer patients are not ideal due to the high recurrence rate of the disease. Therefore, many researchers are exploring new specific therapeutic methods that are highly curative and minimally cytotoxic to healthy tissues. To this end, albumin nanospheres simultaneously were loaded with super-paramagnetic iron oxide nanoparticles (as gene vector and anticancer gene), and plasmid pDONR223-IFNG, and modified with anti-EGFR monoclonal antibody cetuximab as therapy. Targeting agents, namely gene-loaded immunomagnetic albumin nanospheres (cetuximab [C225]-IFNG-IMANS), were prepared for targeted lung carcinoma cells (GLC-82 cell lines). Transmission electron microscopy images showed that the C225-IFNG-IMANS were successfully prepared, and the ability of the nanospheres to target GLC-82 cells in vitro was confirmed by Prussian blue staining, immunofluorescence experiments, and magnetic resonance imaging. Transfection photographs and agarose gel electrophoresis proved that pDONR223-IFNG could be encased in the albumin nanospheres. A Cell Counting Kit-8 assay showed that the combination therapy group had significantly more therapeutic effects on GLC-82 cells than other therapy groups. A flow cytometry assay showed that the apoptotic index of the combined treatment group was 67.68%, whereas the indices of the C225 group, gene therapy group, and magnetic fluid hyperthermia group were 12.2%, 16.34%, and 20.04% respectively. Therefore, the combination of thermal treatment, molecular targeted treatment, and gene treatment synergistically targets GLC-82 cells, and the use of C225-IFNG-IMANS as a gene or drug carrier offers a novel and promising approach for the treatment of lung cancer.

Antitumor Activity of Doxorubicin-Loaded Carbon Nanotubes Incorporated Poly(Lactic-Co-Glycolic Acid) Electrospun Composite Nanofibers

The drug-loaded composite electrospun nanofiber has attracted more attention in biomedical field, especially in cancer therapy. In this study, a composite nanofiber was fabricated by electrospinning for cancer treatment. Firstly, the carbon nanotubes (CNTs) were selected as carriers to load the anticancer drug-doxorubicin (DOX) hydrochloride. Secondly, the DOX-loaded CNTs (DOX@CNTs) were incorporated into the poly(lactic-co-glycolic acid) (PLGA) nanofibers via electrospinning. Finally, a new drug-loaded nanofibrous scaffold (PLGA/DOX@CNTs) was formed. The properties of the prepared composite nanofibrous mats were characterized by various techniques. The release profiles of the different DOX-loaded nanofibers were measured, and the in vitro antitumor efficacy against HeLa cells was also evaluated. The results showed that DOX-loaded CNTs can be readily incorporated into the nanofibers with relatively uniform distribution within the nanofibers. More importantly, the drug from the composite nanofibers can be released in a sustained and prolonged manner, and thereby, a significant antitumor efficacy in vitro is obtained. Thus, the prepared composite nanofibrous mats are a promising alternative for cancer treatment.

Protein-based photothermal theranostics for imaging-guided cancer therapy

The development of imageable photothermal theranostics has attracted considerable attention for imaging guided photothermal therapy (PTT) with high tumor ablation accuracy. In this study, we strategically constructed a near-infrared (NIR) cyanine dye by introducing a rigid cyclohexenyl ring to the heptamethine chain to obtain a heptamethine dye CySCOOH with high fluorescence intensity and good stability. By covalent conjugation of CySCOOH onto human serum albumin (HSA), the as-prepared HSA@CySCOOH nanoplatform is highly efficient for NIR fluorescence/photoacoustic/thermal multimodality imaging and photothermal tumor ablation. The theranostic capability of HSA@CySCOOH was systematically evaluated both in vitro and in vivo. Most intriguingly, complete tumor elimination was achieved by intravenous injection of HSA@CySCOOH (CySCOOH, 1 mg kg(-1); 808 nm, 1.0 W cm(-2) for 5 min) into 4T1 tumor-bearing mice, with no weight loss, noticeable toxicity, or tumor recurrence being observed. This as-prepared protein-based nanotheranostics exhibits high water dispersibility, no off target cytotoxicity, and good biodegradability and biocompatibility, thus facilitating its clinical translation to cancer photothermal theranostics.

Aptamer loaded MoS2 nanoplates as nanoprobes for detection of intracellular ATP and controllable photodynamic therapy

In this work we designed a MoS2 nanoplate-based nanoprobe for fluorescence imaging of intracellular ATP and photodynamic therapy (PDT) via ATP-mediated controllable release of (1)O2. The nanoprobe was prepared by simply assembling a chlorine e6 (Ce6) labelled ATP aptamer on MoS2 nanoplates, which have favorable biocompatibility, unusual surface-area-to-mass ratio, strong affinity to single-stranded DNA, and can quench the fluorescence of Ce6. After the nanoprobe was internalized into the cells and entered ATP-abundant lysosomes, its recognition to ATP led to the release of the single-stranded aptamer from MoS2 nanoplates and thus recovered the fluorescence of Ce6 at an excitation wavelength of 633 nm, which produced a highly sensitive and selective method for imaging of intracellular ATP. Meanwhile, the ATP-mediated release led to the generation of (1)O2 under 660 nm laser irradiation, which could induce tumor cell death with a lysosomal pathway. The controllable PDT provided a model approach for design of multifunctional theranostic nanoprobes. These results also promoted the development and application of MoS2 nanoplate-based platforms in biomedicine.

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.

A pH-activatable and aniline-substituted photosensitizer for near-infrared cancer theranostics

A trifunctional photosensitizer was designed to achieve highly selective near-infrared tumor imaging, efficient photodynamic therapy and therapeutic self-monitoring.

This work reports a newly designed pH-activatable and aniline-substituted aza-boron-dipyrromethene as a trifunctional photosensitizer to achieve highly selective tumor imaging, efficient photodynamic therapy (PDT) and therapeutic self-monitoring through encapsulation in a cRGD-functionalized nanomicelle. The diethylaminophenyl is introduced in to the structure for pH-activatable near-infrared fluorescence and singlet oxygen (¹O₂) generation, and bromophenyl is imported to increase the ¹O₂ generation efficiency upon pH activation by virtue of its heavy atom effect. After encapsulation, the nanoprobe can target α_vβ₃ integrin-rich tumor cells via cRGD and is activated by physiologically acidic pH for cancer discrimination and PDT. The fascinating advantage of the nanoprobe is near-infrared implementation beyond 800 nm, which significantly improves the imaging sensitivity and increases the penetration depth of the PDT. By monitoring the fluorescence decrease in the tumor region after PDT, the therapeutic efficacy is demonstrated in situ and in real time, which provides a valuable and convenient self-feedback function for PDT efficacy tracking. Therefore, this rationally designed and carefully engineered nanoprobe offers a new paradigm for precise tumor theranostics and may provide novel opportunities for future clinical cancer treatment.

In vivo targeted magnetic resonance imaging and visualized photodynamic therapy in deep-tissue cancers using folic acid-functionalized superparamagnetic-upconversion nanocomposites

Multifunctional nanoprobes used in magnetic resonance imaging (MRI) and photodynamic therapy (PDT) also have potential applications in diagnosis and visualized therapy of cancers, and hence it is important to investigate the active-targeting ability and in vivo reliability of these nanoprobes. In this work, folic acid (FA)-targeted, photosensitizer (PS)-loaded Fe3O4@NaYF4:Yb/Er (FA-NPs-PS) nanocomposites were synthesized for in vivo T2-weighted MRI and visualized PDT of cancers by modeling MCF-7 tumor-bearing nude mice. By measuring the upconversion luminescence (UCL) and fluorescence emission spectra, the as-prepared FA-NPs-PS nanocomposites showed near-infrared (NIR)-triggered PDT performance due to the production of a singlet oxygen species. Moreover, by tracing PS fluorescence in MCF-7, HeLa cells and in MCF-7 tumors, the FA-targeted nanocomposites demonstrated good targeting ability both in vitro and in vivo. Under the irradiation of a 980 nm laser, the viabilities of MCF-7 and HeLa cells incubated with FA-NPs-PS nanocomposites could decrease to about 18.4% and 30.7%, respectively, and the inhibition of MCF-7 tumors could reach about 94.9%. The transverse MR relaxivity of 63.79 mM(-1) s(-1) (r2 value) and in vivo MR imaging of MCF-7 tumors indicated an excellent T2-weighted MR performance. This work demonstrated that FA-targeted MRI/PDT nanoprobes are effective for in vivo diagnosis and visualized therapy of breast cancers.

Smart MoS2/Fe3O4 Nanotheranostic for Magnetically Targeted Photothermal Therapy Guided by Magnetic Resonance/Photoacoustic Imaging

The ability to selectively destroy cancer cells while sparing normal tissue is highly desirable during the cancer therapy. Here, magnetic targeted photothermal therapy was demonstrated by the integration of MoS₂ (MS) flakes and Fe₃O₄ (IO) nanoparticles (NPs), where MoS₂ converted near-infrared (NIR) light into heat and Fe₃O₄ NPs served as target moiety directed by external magnetic field to tumor site. The MoS₂/Fe₃O₄ composite (MSIOs) functionalized by biocompatible polyethylene glycol (PEG) were prepared by a simple two-step hydrothermal method. And the as-obtained MSIOs exhibit high stability in bio-fluids and low toxicity in vitro and in vivo. Specifically, the MSIOs can be applied as a dual-modal probe for T₂-weighted magnetic resonance (MR) and photoacoustic tomography (PAT) imaging due to their superparamagnetic property and strong NIR absorption. Furthermore, we demonstrate an effective result for magnetically targeted photothermal ablation of cancer. All these results show a great potential for localized photothermal ablation of cancer spatially/timely guided by the magnetic field and indicated the promise of the multifunctional MSIOs for applications in cancer theranostics.

Design of magnetic nanoparticles for hepatocellular carcinoma treatment using the control mechanisms of the cell internal nucleus and external membrane

Nanoparticle drugs and relevant treatment technologies have achieved widespread attention in recent years. Hepatocellular carcinoma (HCC) remains a challenging malignancy of worldwide importance since it is one of the worst malignant tumors. In this study, magnetic Fe₃O₄ nanoparticles are prepared via a co-precipitation reaction with self-assembled surface monolayers of oleic acid molecules. For synthesizing the nanoparticle anti-tumor drug used against HCC, the liquid photo-immobilization method is used to bond the photoactive N-isopropylacrylamide derivative (NIPAm-AA) onto the oleic acid monolayer for subsequently embedding doxorubicin, photoactive tumor necrosis factor-α (TNF-α)/interferon-γ (IFN-γ), and folic acid (FOL). We investigate how the nanoparticle drug inhibits the growth of human hepatocellular carcinoma HepG2 cells in vitro and in vivo. Remarkably, our characterizations show that the nanoparticle drug demonstrates much higher anticancer efficacy (94.7%) in vitro than previously reported drugs. It is revealed that the programmed cell death induced by the drug is mainly oncosis, a new programmed cell death pathway, different from earlier proposed mechanisms. This oncosis mechanism is also confirmed in the other two hepatocellular carcinoma cells (BEL-7402 and Huh-7). This study may be helpful for developing a new type of nanoparticle drug capable of assuring molecular control of both the cell inner nucleus and outer membrane as a means to enormously increase the drug efficacy in human hepatocellular carcinoma.

Analysis of the in vivo and in vitro effects of photodynamic therapy on breast cancer by using a sensitizer, sinoporphyrin sodium

Photodynamic therapy (PDT) is an emerging theranostic modality for various cancers and diseases. Photosensitizers are critical components for PDT. Sinoporphyrin sodium, referred to as DVDMS, is a newly identified photosensitizer that was isolated from Photofrin. Here, we evaluated the effects of DVDMS-mediated PDT (DVDMS-PDT) on tumor cell proliferation and metastasis in the highly metastatic 4T1 cell line and a mouse xenograft model. DVDMS-PDT elicited a potent phototoxic effect in vitro, which was abolished using the reactive oxygen species (ROS) scavenger N-acetylcysteine. In addition, DVDMS-PDT effectively inhibited the migration of 4T1 cells in scratch wound-healing and transwell assays. Using an in vivo mouse model, DVDMS-PDT greatly prolonged the survival time of tumor-bearing mice and inhibited tumor growth and lung metastasis, consistent with in vitro findings. PDT with DVDMS had a greater anti-tumor efficacy than clinically used Photofrin. Moreover, preliminary toxicological results indicate that DVDMS is relatively safe. These results suggest that DVDMS is a promising sensitizer that warrants further development for use in cancer treatment with PDT or other sensitizing agent-based therapies.

Multifunctional calcium phosphate nanoparticles for combining near-infrared fluorescence imaging and photodynamic therapy

Photodynamic therapy (PDT) of tumors causes skin photosensitivity as a result of unspecific accumulation behavior of the photosensitizers. PDT of tumors was improved by calcium phosphate nanoparticles conjugated with (i) Temoporfin as a photosensitizer, (ii) the RGDfK peptide for favored tumor targeting and (iii) the fluorescent dye molecule DY682-NHS for enabling near-infrared fluorescence (NIRF) optical imaging in vivo. The nanoparticles were characterized with regard to size, spectroscopic properties and uptake into CAL-27 cells. The nanoparticles had a hydrodynamic diameter of approximately 200 nm and a zeta potential of around +22mV. Their biodistribution at 24h after injection was investigated via NIRF optical imaging. After treating tumor-bearing CAL-27 mice with nanoparticle-PDT, the therapeutic efficacy was assessed by a fluorescent DY-734-annexin V probe at 2 days and 2 weeks after treatment to detect apoptosis. Additionally, the contrast agent IRDye® 800CW RGD was used to assess tumor vascularization (up to 4 weeks after PDT). After nanoparticle-PDT in mice, apoptosis in the tumor was detected after 2 days. Decreases in tumor vascularization and tumor volume were detected in the next few days. Calcium phosphate nanoparticles can be used as multifunctional tools for NIRF optical imaging, PDT and tumor targeting as they exhibited a high therapeutic efficacy, being capable of inducing apoptosis and destroying tumor vascularization.

Optical and photoacoustic dual-modality imaging guided synergistic photodynamic/photothermal therapies

Phototherapies such as photodynamic therapy (PDT) and photothermal therapy (PTT), due to their specific spatiotemporal selectivity and minimal invasiveness, have been widely investigated as alternative treatments of malignant diseases. Graphene and its derivatives not only have been used as carriers to deliver photosensitizers for PDT, but also as photothermal conversion agents (PTCAs) for PTT. Herein, we strategically designed and produced a novel photo-theranostic platform based on sinoporphyrin sodium (DVDMS) photosensitizer-loaded PEGylated graphene oxide (GO-PEG-DVDMS) for enhanced fluorescence/photoacoustic (PA) dual-modal imaging and combined PDT and PTT. The GO-PEG carrier drastically improves the fluorescence of loaded DVDMS via intramolecular charge transfer. Concurrently, DVDMS significantly enhances the near-infrared (NIR) absorption of GO for improved PA imaging and PTT. The cancer theranostic capability of the as-prepared GO-PEG-DVDMS was carefully investigated both in vitro and in vivo. This novel theranostics is well suited for fluorescence/PA dual-modal imaging and synergistic PDT/PTT.

Enhanced fluorescence imaging guided photodynamic therapy of sinoporphyrin sodium loaded graphene oxide

Extensive research indicates that graphene oxide (GO) can effectively deliver photosensitives (PSs) by π-π stacking for photodynamic therapy (PDT). However, due to the tight complexes of GO and PSs, the fluorescence of PSs are often drastically quenched via an energy/charge transfer process, which limits GO-PS systems for photodiagnostics especially in fluorescence imaging. To solve this problem, we herein strategically designed and prepared a novel photo-theranostic agent based on sinoporphyrin sodium (DVDMS) loaded PEGylated GO (GO-PEG-DVDMS) with improved fluorescence property for enhanced optical imaging guided PDT. The fluorescence of loaded DVDMS is drastically enhanced via intramolecular charge transfer. Meanwhile, the GO-PEG vehicles can significantly increase the tumor accumulation efficiency of DVDMS and lead to an improved PDT efficacy as compared to DVDMS alone. The cancer theranostic capability of the as-prepared GO-PEG-DVDMS was carefully investigated both in vitro and in vivo. Most intriguingly, 100% in vivo tumor elimination was achieved by intravenous injection of GO-PEG-DVDMS (2 mg/kg of DVDMS, 50 J) without tumor recurrence, loss of body weight or other noticeable toxicity. This novel GO-PEG-DVDMS theranostics is well suited for enhanced fluorescence imaging guided PDT.

Photosensitizer conjugated iron oxide nanoparticles for simultaneous in vitro magneto-fluorescent imaging guided photodynamic therapy

A hybrid nanoparticle composed of a photodynamic agent pheophorbide A linked with Fe₃O₄ through heparin and APTES for MR imaging and phototherapy.

Surface Functionalization of Chemically Reduced Graphene Oxide for Targeted Photodynamic Therapy

In this study, using chemically reduced graphene oxide (GO) as a model nanocarbon, we successfully developed a facile surface-functionalization strategy of nanocarbons to allow both biocompatibility and receptor targeted drug delivery. Polyvinylpyrrolidone (PVP) coating improves aqueous dispersibility and biocompatibility of GO, and provides anchoring sites for ACDCRGDCFCG peptide (RGD4C). Aromatic photosensitizer chlorin e6 (Ce6) can be effectively loaded into the rGO-PVP-RGD system via hydrophobic interactions and π-π stacking. The nanodelivery system can significantly increase the accumulation of Ce6 in tumor cells and lead to an improved photodynamic therapy (PDT) efficacy as compared to Ce6 alone. The facile surface functionalization strategy can be applied to other nanomaterials such as carbon nanotubes, and inorganic nanomaterials.

Aptamer-functionalized gold nanoparticles as photoresponsive nanoplatform for co-drug delivery

Various platforms have been developed as innovative nanocarriers to deliver therapeutic agents to the diseased sites. Multifunctional surface modification allows an enhanced recognition and uptake of drug carriers by targeted cells. However, the development of drug resistance in some tumor cells plays a major role in the failure of chemotherapy. Drugs given in combination, called multidrug delivery approach, was designed to improve the therapeutic efficacy and has become an increasingly used strategy that is of great importance in clinical cancer treatments. In this study, aptamer-functionalized gold nanoparticles (Au NPs) have been used as a nanoplatform to codeliver two different anticancer drugs for improving the drug effectiveness. The surface of Au NPs (13 nm in diameter) was assembled with AS1411 aptamers, which tethered with 21-base pairs of (CGATCGA)3 sequence approached to the Au NPs. Both the photosensitizer 5,10,15,20-tetrakis(1-methylpyridinium-4-yl) porphyrin (TMPyP4) and the chemotherapeutic drug doxorubicin (Dox) were then physically attached to the AS1411-conjugated Au NPs (T/D:ds-NPs) and delivered to the target tumor cells such as HeLa and Dox-resistant MCF-7R cell lines. When exposed to a 632 nm light, reactive oxygen species induced by TMPyP4 molecules were generated inside the living cells, followed by cell damage. In addition, triggered release of the complementary drugs also occurred simultaneously during the photodynamic reaction. In the presence of Dox molecules, the toxicity toward the target cells was superior to individual drug treatment. Overall, a co-drug delivery platform was successfully established to improve the therapeutic efficacy in tumor cells. The improvement of the photodynamic-stimulated triggered release was enhanced, thus highly promising precise drug release in targeted drug delivery.

PET and NIR optical imaging using self-illuminating (64)Cu-doped chelator-free gold nanoclusters

Self-illuminating fluorescence imaging without autofluorescence background interference has recently aroused more research interests in molecular imaging. Currently, only a few self-illuminating probes were developed, based mainly on toxic quantum dots such as CdSe, CdTe. Herein, we report a novel design of nontoxic self-illuminating gold nanocluster ((64)Cu-doped AuNCs) for dual-modality positron emission tomography (PET) and near-infrared (NIR) fluorescence imaging based on Cerenkov resonance energy transfer (CRET). PET radionuclide (64)Cu was introduced by a chelator-free doping method, which played dual roles as the energy donor and the PET imaging source. Meanwhile, AuNCs acted as the energy acceptor for NIR fluorescence imaging. (64)Cu-doped AuNCs exhibited efficient CRET-NIR and PET imaging both in vitro and in vivo. In a U87MG glioblastoma xenograft model, (64)Cu-doped AuNCs showed high tumor uptake (14.9 %ID/g at 18 h) and produced satisfactory tumor self-illuminating NIR images in the absence of external excitation. This self-illuminating nanocluster with non-toxicity and good biocompatibility can be employed as a novel imaging contrast agent for biomedical applications, especially for molecular imaging.

Thermosensitive liposome formulated indocyanine green for near-infrared triggered photodynamic therapy: in vivo evaluation for triple-negative breast cancer

PURPOSE

The focus of this research was to formulate and evaluate a theranostic liposomal delivery system using indocyanine green (ICG) as a photosensitizer, triggered by near infrared (NIR) irradiation, for in vivo photodynamic therapy (PDT) of breast cancer.

METHODS

Cytotoxicity of PDT using liposomal ICG (LPICG) as well as free ICG (FRICG) was evaluated in the human MDA-MB-468 triple-negative breast cancer (TNBC) cell line. NIR irradiation-induced increase in temperature was also monitored both in vitro and in vivo. Quantitative pharmacokinetic profile and fluorescence imaging-based biodistribution patterns of both formulations were obtained using the human TNBC xenograft model in nude mice. Overall safety, tolerability, and long-term anti-tumor efficacy of LPICG versus FRICG-mediated PDT was evaluated.

RESULTS

Significant loss of cell viability was achieved following photoactivation of LPICG via NIR irradiation. Temperatures of irradiated LPICG increased with increasing concentrations of loaded ICG, which correlated with significant rise of temperature compared to PBS in vivo (p < 0.01). Pharmacokinetic assessment revealed a significant increase in systemic distribution and circulation half-life of LPICG, and NIR fluorescence imaging demonstrated enhanced accumulation of liposomes within the tumor region. Tumor growth in mice treated with LPICG followed by NIR irradiation was significantly reduced compared to those treated with FRICG, saline, and irradiation alone.

CONCLUSIONS

In vivo photodynamic therapy using LPICG demonstrated targeted biodistribution and superior anti-tumor efficacy in a human TNBC xenograft model compared to FRICG. In addition, this unique delivery system exhibited a promising role in NIR image-guided delivery and real-time biodistribution monitoring of formulation with ICG serving as the fluorescent probe.

Multifunctional theranostic red blood cells for magnetic-field-enhanced in vivo combination therapy of cancer

Red blood cells are attached to iron oxide nanoparticles pre-coated with chlorine e6, a photosensitizer, and then loaded with a chemotherapeutic drug, doxorubicin, to enable imaging-guided combined photodynamic and chemotherapy of cancer, achieving excellent synergistic therapeutic effects in an animal tumor model. This work highlights the great promise of integrating cell-based drug-delivery systems with nanotechnology as a biocompatible multifunctional platform for applications in cancer theranostics.

Efficient pH dependent drug delivery to target cancer cells by gold nanoparticles capped with carboxymethyl chitosan

Doxorubicin (DOX) was immobilized on gold nanoparticles (AuNPs) capped with carboxymethyl chitosan (CMC) for effective delivery to cancer cells. The carboxylic group of carboxymethyl chitosan interacts with the amino group of the doxorubicin (DOX) forming stable, non-covalent interactions on the surface of AuNPs. The carboxylic group ionizes at acidic pH, thereby releasing the drug effectively at acidic pH suitable to target cancer cells. The DOX loaded gold nanoparticles were effectively absorbed by cervical cancer cells compared to free DOX and their uptake was further increased at acidic conditions induced by nigericin, an ionophore that causes intracellular acidification. These results suggest that DOX loaded AuNPs with pH-triggered drug releasing properties is a novel nanotheraputic approach to overcome drug resistance in cancer.

Dual imaging-guided photothermal/photodynamic therapy using micelles

We report a type of photosensitizer (PS)-loaded micelles integrating cyanine dye as potential theranostic micelles for precise anatomical tumor localization via dual photoacoustic (PA)/near-infrared fluorescent (NIRF) imaging modalities, and simultaneously superior cancer therapy via sequential synergistic photothermal therapy (PTT)/photodynamic therapy (PDT). The micelles exhibit enhanced photostability, cell internalization and tumor accumulation. The dual NIRF/PA imaging modalities of the micelles cause the high imaging contrast and spatial resolution of tumors, which provide precise anatomical localization of the tumor and its inner vasculature for guiding PTT/PDT treatments. Moreover, the micelles can generate severe photothermal damage on cancer cells and destabilization of the lysosomes upon PTT photoirradiation, which subsequently facilitate synergistic photodynamic injury via PS under PDT treatment. The sequential treatments of PTT/PDT trigger the enhanced cytoplasmic delivery of PS, which contributes to the synergistic anticancer efficacy of PS. Our strategy provides a dual-modal cancer imaging with high imaging contrast and spatial resolution, and subsequent therapeutic synergy of PTT/PDT for potential multimodal theranostic application.

Fluorescent drug-loaded, polymeric-based, branched gold nanoshells for localized multimodal therapy and imaging of tumoral cells

Here we report the synthesis of PLGA/DOXO-core Au-branched shell nanostructures (BGNSHs) functionalized with a human serum albumin/indocyanine green/folic acid complex (HSA-ICG-FA) to configure a multifunctional nanotheranostic platform. First, branched gold nanoshells (BGNSHs) were obtained through a seeded-growth surfactant-less method. These BGNSHs were loaded during the synthetic process with the chemotherapeutic drug doxorubicin, a DNA intercalating agent and topoisomerase II inhibitior. In parallel, the fluorescent near-infrared (NIR) dye indocyanine green (ICG) was conjugated to the protein human serum albumin (HSA) by electrostatic and hydrophobic interactions. Subsequently, folic acid was covalently attached to the HSA-ICG complex. In this way, we created a protein complex with targeting specificity and fluorescent imaging capability. The resulting HSA-ICG-FA complex was adsorbed to the gold nanostructures surface (BGNSH-HSA-ICG-FA) in a straightforward incubation process thanks to the high affinity of HSA to gold surface. In this manner, BGNSH-HSA-ICG-FA platforms were featured with multifunctional abilities: the possibility of fluorescence imaging for diagnosis and therapy monitoring by exploiting the inherent fluorescence of the dye, and a multimodal therapy approach consisting of the simultaneous combination of chemotherapy, provided by the loaded drug, and the potential cytotoxic effect of photodynamic and photothermal therapies provided by the dye and the gold nanolayer of the hybrid structure, respectively, upon NIR light irradiation of suitable wavelength. The combination of this trimodal approach was observed to exert a synergistic effect on the cytotoxicity of tumoral cells in vitro. Furthermore, FA was proved to enhance the internalization of nanoplatform. The ability of the nanoplatforms as fluorescence imaging contrast agents was tested by preliminary analyzing their biodistribution in vivo in a tumor-bearing mice model.

Bifunctional nanoparticles with magnetism and NIR fluorescence: controlled synthesis from combination of AGET ATRP and 'click' reaction

In this work, bifunctional nanoparticles (NPs) capable of emitting near infrared (NIR) fluorescence and generating superparamagnetism under an external magnetic field were prepared by combination of 'click' reaction and surface-initiated activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) of water-soluble poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) and glycidyl methacrylate (GMA) using biocompatible iron as the catalyst on the surface of silica-coated iron oxide (Fe3O4@SiO2) NPs. The nanosized Fe3O4@SiO2@PPEGMA-co-PGMA@N3 was prepared through AGET ATRP and alkynyl bearing NIR dye was also prepared; afterwards they were integrated together by 'click' reaction. The different stages of surface modification were approved by employing different characterization techniques such as TEM, XRD, XPS, VSM and FT-IR, and the properties of the final NPs were thoroughly studied. Their suitability as dual model imaging agents for magnetic resonance (MR) and fluorescence imaging was investigated, indicating them to be a competitive candidate for imaging contrast agents.

4-aminobenzoic acid-coated maghemite nanoparticles as potential anticancer drug magnetic carriers: a case study on highly cytotoxic Cisplatin-like complexes involving 7-azaindoles

This study describes a one-pot synthesis of superparamagnetic maghemite-based 4-aminobenzoic acid-coated spherical core-shell nanoparticles (PABA@FeNPs) as suitable nanocomposites potentially usable as magnetic carriers for drug delivery. The PABA@FeNPs system was subsequently functionalized by the activated species (1* and 2*) of highly in vitro cytotoxic cis-[PtCl2(3Claza)2] (1; 3Claza stands for 3-chloro-7-azaindole) or cis-[PtCl2(5Braza)2] (2; 5Braza stands for 5-bromo-7-azaindole), which were prepared by a silver(I) ion assisted dechlorination of the parent dichlorido complexes. The products 1*@PABA@FeNPs and 2*@PABA@FeNPs, as well as an intermediate PABA@FeNPs, were characterized by a combination of various techniques, such as Mössbauer, FTIR and EDS spectroscopy, thermal analysis, SEM and TEM. The results showed that the products consist of well-dispersed maghemite-based nanoparticles of 13 nm average size that represent an easily obtainable system for delivery of highly cytotoxic cisplatin-like complexes in oncological practice.

Solubilization, dispersion and stabilization of magnetic nanoparticles in water and non-aqueous solvents: recent trends

Solubilization and stabilization techniques for magnetic nanoparticles in water and in non-aqueous solvents are reviewed.

Multifunctional iron oxide/silk-fibroin (Fe3O4–SF) composite microspheres for the delivery of cancer therapeutics

In this article, we report novel multifunctional iron oxide/silk-fibroin (Fe₃O₄–SF) microspheres synthesized by simple salting out process.

Biodegradable gold nanovesicles with an ultrastrong plasmonic coupling effect for photoacoustic imaging and photothermal therapy

The hierarchical assembly of gold nanoparticles (GNPs) allows the localized surface plasmon resonance peaks to be engineered to the near-infrared (NIR) region for enhanced photothermal therapy (PTT). Herein we report a novel theranostic platform based on biodegradable plasmonic gold nanovesicles for photoacoustic (PA) imaging and PTT. The disulfide bond at the terminus of a PEG-b-PCL block-copolymer graft enables dense packing of GNPs during the assembly process and induces ultrastrong plasmonic coupling between adjacent GNPs. The strong NIR absorption induced by plasmon coupling and very high photothermal conversion efficiency (η=37%) enable simultaneous thermal/PA imaging and enhanced PTT efficacy with improved clearance of the dissociated particles after the completion of PTT. The assembly of various nanocrystals with tailored optical, magnetic, and electronic properties into vesicle architectures opens new possibilities for the construction of multifunctional biodegradable platforms for biomedical applications.

PEGylated fullerene/iron oxide nanocomposites for photodynamic therapy, targeted drug delivery and MR imaging

Recently, fullerene and fullerene derivatives owning to their highly enriched physical and chemical properties have been widely explored for applications in many different fields including biomedicine. In this study, iron oxide nanoparticles (IONPs) were decorated onto the surface of fullerene (C60), and then PEGylation was performed to improve the solubility and biocompatibility of C60-IONP, obtaining a multi-functional C60-IONP-PEG nanocomposite with strong superparamagnetism and powerful photodynamic therapy capacity. Hematoporphyrin monomethyl ether (HMME), a new photodynamic anti-cancer drug, was conjugated to C60-IONP-PEG, forming a C60-IONP-PEG/HMME drug delivery system, which demonstrated an excellent magnetic targeting ability in cancer therapy. Compared with free HMME, remarkably enhanced photodynamic cancer cell killing effect using C60-IONP-PEG/HMME was realized not only in a cultured B16-F10 cells in vitro but also in an in vivo murine tumor model due to 23-fold higher HMME uptake of tumor and strong photodynamic activity of C60-IONP-PEG. Moreover, C60-IONP-PEG could be further used as a T2-contrast agent for in vivo magnetic resonance imaging. Our work showed C60-IONP-PEG/HMME had a great potential for cancer theranostic applications.

Block copolymer nanoassemblies for photodynamic therapy and diagnosis

Light can be a powerful therapeutic and diagnostic tool. Light-sensitive molecules can be used to develop locally targeted cancer therapeutics. This approach is known as photodynamic therapy (PDT). Similarly, it is possible to diagnose diseases and track the course of treatment in vivo using ligh-sensitive molecules. This methodology is referred to as photodynamic diagnosis (PDD). Despite the potential, many PDT and PDD agents have imperfect physiochemical properties for their successful clinical application. Nanotechnology may solve these issues by improving the viability of PDT and PDD. This review summarizes the current state of PDT and PDD development, the integration of nanotechnology in the field, and the prospective future applications, demonstrating the potential of PDT and PDD for improved cancer treatment and diagnosis.

Facile fabrication of biocompatible and tunable multifunctional nanomaterials via iron-mediated atom transfer radical polymerization with activators generated by electron transfer

A novel strategy of preparing multifunctional nanoparticles (NPs) with near infra red (NIR) fluorescence and magnetism showing good hydrophilicity and low toxicity was developed via surface-initiated atom transfer radical polymerization with activators generated by electron transfer (AGET ATRP) of poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) and glycidyl methacrylate (GMA) employing biocompatible iron as the catalyst on the surface of silica coated iron oxide (Fe3O4@SiO2) NPs. The small molecules (CS2), a NIR fluorescent chromophore, can be fixed into the covalently grafted polymer shell of the NPs by chemical reaction through a covalent bond to obtain stable CS2 dotted NPs Fe3O4@SiO2@PPEGMA-co-PGMA@CS2. The fluorescence intensity of the as-prepared NPs could be conveniently regulated by altering the silica shell thickness (varying the feed of silica source TEOS), CS2 feed, or the feed ratio of VPEGMA/VGMA, which are easily realized in the preparation process. Thorough investigation of the properties of the final NPs including in vivo dual modal imaging indicate that such NPs are one of the competitive candidates as imaging agents proving a promising potential in the biomedical area.

Enhanced upconversion luminescence in NaGdF4:Yb,Er nanocrystals by Fe3+ doping and their application in bioimaging

The visible green and red upconversion emissions in Er(3+)/Yb(3+) doped β-NaGdF4 nanoparticles were enhanced by tridoping with Fe(3+) ions (0-40 mol%). XRD, XPS, ICP-AES and EDS data demonstrated successful incorporation of Fe(3+) ions in NaGdF4:Yb(3+)/Er(3+) nanoparticles. The effect of Fe(3+) tridoping on the upconversion luminescence in NaGdF4:Yb(3+)/Er(3+) NPs was investigated in detail. The green and red emission intensities were enhanced by 34 and 30 times, respectively. The maximum emission was observed in a sample containing 30 mol% Fe(3+) ions. A possible mechanism for the enhanced upconversion emission is proposed. In addition, a layer of silica was coated onto the surface of UCNPs to improve the biocompatibility. Folic acid was covalently linked to the silica coated UCNPs to form UCNP@SiO2-FA nanoprobes, which have been successfully applied to the fluorescent imaging HeLa cells.

Multifunctional nanoprobe for MRI/optical dual-modality imaging and radical scavenging

The development of novel nanomaterials for the diagnosis and/or treatment of human diseases has become an important issue. In this work, a multifunctional theranostic agent was designed by covalently binding hydroxyl- and amino-bearing C60 derivatives (C60 O∼10 (OH)∼16 (NH2 )∼6 (NO2 )∼6 ⋅24 H2 O) with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) to yield C60 O∼10 (OH)∼16 (NH2 )∼6 (NO2 )∼6 ⋅24 H2 O/(Gd-DTPA)3 (DF1 Gd3 ). The obtained DF1 Gd3 shows more than fourfold contrast improvement over commercial Gd-DTPA along with multiwavelength fluorescent emission for dual-modality diagnosis. An inner-ear magnetic resonance imaging (MRI) study was designed as a model of biological barriers, including the blood/brain barrier (BBB) for DF1 Gd3 to investigate its in vivo behavior. This revealed that the fabricated contrast agent dramatically increases the local contrast but can not cross the middle ear/inner ear barrier and endolymph/perilymph barrier in the inner ear, and thus it is also BBB-prohibited in normal individuals. In vivo biodistribution studies suggested that 1) DF1 Gd3 could circulate in vessels for a relatively long time and is mainly eliminated through liver and kidney, 2) DF1 Gd3 may potentially function as a liver-specific MRI contrast agent. Interestingly, DF1 Gd3 also shows an excellent quenching effect on hydroxyl radicals, as revealed by the DMPO spin trap/ESR method. The combination of enhanced MRI/FL imaging and local treatment of lesions is unique to DF1 Gd3 and potentiates the medical paradigm of "detect and treat/prevent" in combating human diseases related to reactive oxygen.

PEG-functionalized iron oxide nanoclusters loaded with chlorin e6 for targeted, NIR light induced, photodynamic therapy

Magnetic targeting that utilizes a magnetic field to specifically delivery theranostic agents to targeted tumor regions can greatly improve the cancer treatment efficiency. Herein, we load chlorin e6 (Ce6), a widely used PS molecule in PDT, on polyethylene glycol (PEG) functionalized iron oxide nanoclusters (IONCs), obtaining IONC-PEG-Ce6 as a theranostic agent for dual-mode imaging guided and magnetic-targeting enhanced in vivo PDT. Interestingly, after being loaded on PEGylated IONCs, the absorbance/excitation peak of Ce6 shows an obvious red-shift from ~650 nm to ~700 nm, which locates in the NIR region with improved tissue penetration. Without noticeable dark toxicity, Ce6 loaded IONC-PEG (IONC-PEG-Ce6) exhibits significantly accelerated cellular uptake compared with free Ce6, and thus offers greatly improved in vitro photodynamic cancer cell killing efficiency under a low-power light exposure. After demonstrating the magnetic field (MF) enhanced PDT using IONC-PEG-Ce6, we then further test this concept in animal experiments. Owing to the strong magnetism of IONCs and the long blood-circulation time offered by the condensed PEG coating, IONC-PEG-Ce6 shows strong MF-induced tumor homing ability, as evidenced by in vivo dual modal optical and magnetic resonance (MR) imaging. In vivo PDT experiment based magnetic tumor targeting using IONC-PEG-Ce6 is finally carried out, achieving high therapeutic efficacy with dramatically delayed tumor growth after just a single injection and the MF-enhanced photodynamic treatment. Considering the biodegradability and non-toxicity of iron oxide, our IONC-PEG-Ce6 presented in this work may be a useful multifunctional agent promising in photodynamic cancer treatment under magnetic targeting.

VEGF-loaded graphene oxide as theranostics for multi-modality imaging-monitored targeting therapeutic angiogenesis of ischemic muscle

Herein we report the design and synthesis of multifunctional VEGF-loaded IR800-conjugated graphene oxide (GO-IR800-VEGF) for multi-modality imaging-monitored therapeutic angiogenesis of ischemic muscle. The as-prepared GO-IR800-VEGF positively targets VEGF receptors, maintains an elevated level of VEGF in ischemic tissues for a prolonged time, and finally leads to remarkable therapeutic angiogenesis of ischemic muscle. Although more efforts are required to further understand the in vivo behaviors and the long-term toxicology of GO, our work demonstrates the success of using GO for efficient VEGF delivery in vivo by intravenous administration and suggests the great promise of using graphene oxide in theranostic applications for treating ischemic disease.

Photosensitizer-loaded gold vesicles with strong plasmonic coupling effect for imaging-guided photothermal/photodynamic therapy

A multifunctional theranostic platform based on photosensitizer-loaded plasmonic vesicular assemblies of gold nanoparticles (GNPs) is developed for effective cancer imaging and treatment. The gold vesicles (GVs) composed of a monolayer of assembled GNPs show strong absorbance in the near-infrared (NIR) range of 650-800 nm, as a result of the plasmonic coupling effect between neighboring GNPs in the vesicular membranes. The strong NIR absorption and the capability of encapsulating photosensitizer Ce6 in GVs enable trimodality NIR fluorescence/thermal/photoacoustic imaging-guided synergistic photothermal/photodynamic therapy (PTT/PDT) with improved efficacy. The Ce6-loaded GVs (GV-Ce6) have the following characteristics: (i) high Ce6 loading efficiency (up to ~18.4 wt %; (ii) enhanced cellular uptake efficiency of Ce6; (iii) simultaneous trimodality NIR fluorescence/thermal/photoacoustic imaging; (iv) synergistic PTT/PDT treatment with improved efficacy using single wavelength continuous wave laser irradiation.