Photoinduced electron transfer in zinc phthalocyanine loaded on single-walled carbon nanohorns in aqueous solution

Preparation of zinc phthalocyanine-loaded amphiphilic phosphonium chitosan nanomicelles for enhancement of photodynamic therapy efficacy

To increase the solubility and the encapsulation of zinc phthalocyanine (ZnPc) photosensitizer for photodynamic therapy (PDT), a positively charged amphiphilic phosphonium chitosan nanomicelle with multi-benzene structure was developed, and its application to PDT was explored. N-acetyl-l-phenylalanine-(4-carboxybutyl) triphenylphosphonium bromide chitosan (CTPB-CS-NAP), a chitosan derivative with tunable amphiphilicity, was synthesized first. ZnPc was encapsulated in CTPB-CS-NAP at the critical micelle concentration (CMC) of 4.898 mg/L by a hydrophobic self-assembly method to form ZnPc-loaded nanomicelles (ZnPc@CTPB-CS-NAP). The method gives the highest encapsulation efficiency and drug loading of 89.4 % and 22.3 %, respectively. ZnPc@CTPB-CS-NAP is stably dispersed in aqueous solution and shows the average particle size of 103±5 nm. PDT experiments suggest the phototoxicity of ZnPc@CTPB-CS-NAP is much higher than that of ZnPc, but no obvious dark cytotoxicity is observed. Our study has provided a new strategy for improving the photodynamic therapy efficacy of hydrophobic photosensitizer by the encapsulation with chitosan derivative carriers.

Functionalized Carbon Nanohorns as Drug Delivery Platforms

Carbon nanohorns (CNHs) resembling a single-layered graphene sheet wrapped in a conical shape can be chemically modified in order to immobilize, carry, and release biologically active molecules. Here, we describe the major routes for the preparation of CNH-based drug delivery platforms, via covalent coupling and encapsulation, proficient to facilitate the design of sophisticated drug nanocarriers.

Carbon nanohorn/liposome systems: Preformulation, design and in vitro toxicity studies

In the present work, the convergence of two different drug delivery systems is investigated, namely the combination of carbon nanohorns (CNHs) and liposomes. Our effort initially included the synthesis of two conversely charged carbon nanohorns and their subsequent analysis through various methods. The study of their effect on the thermotropic behavior of artificial membranes provided an essential assistance for the upcoming liposome preparation, which were estimated for their physicochemical properties. The presence of CNHs alters the calorimetric parameters of the lipids. We also prepared CNHs:liposome systems. The characteristic morphology and secondary spherical superstructure of CNHs is retained in the chimeric materials, suggesting that the interactions with the liposomes do not alter the dahlia-flower-like aggregation of CNHs. Both CNHs-liposome systems exhibit a relatively small cellular cytotoxicity in vitro, tested in mouse embryonic fibroblasts. To summarize, we developed CNHs:liposome platforms with a complete knowledge of their thermotropic, physicochemical, morphological and nanotoxicological characteristics.

Hypericin-Loaded Carbon Nanohorn Hybrid for Combined Photodynamic and Photothermal Therapy in Vivo

Photodynamic therapy (PDT) of hypericin (Hyp) is hampered by poor water solubility and photostability. Incorporation of photosensitizers into nanocarriers has been designed to solve these issues. Herein, SWNH-Hyps nanohybrids were first fabricated by loading hypericin on the surface of single-walled carbon nanohorns (SWNHs) through ??? interaction and exhibited high solubility and stability in aqueous water. SWNH-Hyps could be utilized for a single platform for cancer therapy because it could simultaneously generate enough reactive oxygen species and hyperthermia using light irradiation. Moreover, the SWNHs not only improved water solubility, photostability, and therapy effects of Hyp but also protected it from light degradation. SWNH-Hyps could effectively ablate 4T1 cells by photodynamic/photothermal synergistic therapy upon 590 and 808 nm light irradiations compared with PDT. Furthermore, remarkable tumor cell death as well as tumor growth inhibition was proved via photothermal therapy and PDT of SWNH-Hyps under 590 and 808 nm light irradiations, which demonstrated that synergistic anticancer ability of SWNH-Hyps was better than that of free Hyp in vivo. Such a simple and facile adsorption method improved water solubility of Hyp and then enhanced its therapy effect, which displays that SWNHs can be hopefully used in medicines in the future.

Recent Advances in Carbon Nanomaterials for Cancer Phototherapy

Carbon nanomaterials have received great attention from the scientific community over the past few decades because of their unique physical and chemical properties. In this minireview, we will summarize the recent progress of the use of various carbon nanomaterials in the field of cancer phototherapy. The structural characteristics of each category and the surface functionalization strategies of these nanomaterials will be briefly introduced before focusing on their therapeutic applications. Recent advances on their use in photothermal therapy, photodynamic therapy, and combined phototherapies are presented. Moreover, a few challenges and perspectives on the development of carbon nanomaterials for future theranostics are also discussed.

Spectroscopic study of the loading of cationic porphyrins by carbon nanohorns as high capacity carriers of photoactive molecules to cells

Spherical carbon nanohorns have great potential as drug delivery agents. Here a detailed study of the loading of porphyrin molecules is reported and the influence on their stability described. An optimally loaded sample is shown to cause photoactivated cell death.

Carbon Nanohorns as Reaction Nanochambers - a Systematic Monte Carlo Study

Carbon nanohorns (CNHs, one of the newest carbon allotropes) have been subjected to intensive experimental and theoretical studies due to their potential applications. One of such applications can be their use as reaction nanochambers. However, experimental studies on the reaction equilibria under confinement are extremely challenging since accurate measurements of the concentrations of reacting species in pores are a very hard task. So, the main ways to examine such phenomena are theoretical methods (e.g. the reactive Monte Carlo, RxMC). We have presented the first systematic RxMC study on the influence of the CNH’s geometric parameters (the apex angle, the diameter, and the length) on reaction equilibria, taking the nitrogen monoxide dimerisation as an example. All the investigated parameters significantly affect the reaction yield at low and moderate coverages. Short and narrow CNHs have been found to be preferred. However, the key factor influencing the reaction equilibria is the presence of a conical part. Energetics of interactions between the reacting molecules in this fragment of a nanohorn maximises the effects of confinement. In consequence, CNHs have the advantage over their nanotube counterparts of the same diameter. The obtained results have confirmed that CNHs can be considered as potential reaction nanochambers.

Magnetically-targeted and near infrared fluorescence/magnetic resonance/photoacoustic imaging-guided combinational anti-tumor phototherapy based on polydopamine-capped magnetic Prussian blue nanoparticles

In recent years, Prussian blue (PB)-based nanoagents have become a new platform in photothermal cancer treatment. However, there is little research for PB-based nanoagents to achieve synergistic phototherapy guided by multimodal imaging diagnosis and monitoring. Herein, a novel single wavelength near infrared (NIR) laser-induced magnetically targeted theranostic nanoplatform has been successfully designed and synthesized for the first time based on polydopamine (PDA)/aluminum phthalocyanine (AlPc)/bovine serum albumin (BSA) coated magnetic Prussian blue nanoparticles (Fe₃O₄@PB NPs) for multiple imaging-guided combinatorial cancer therapy. The resultant multifunctional Fe₃O₄@PB@PDA/AlPc/BSA nanocomposites show excellent stability and superparamagnetism, facilitating them to achieve superior photothermal therapy in physiological environments under magnetic guidance. In addition, the delivery vehicles can remarkably increase tumor accumulation of AlPc, thus leading to an enhanced photodynamic therapy efficacy. Furthermore, Fe₃O₄@PB@PDA/AlPc/BSA can be utilized as a multimodality nanoprobe for simultaneous diversified imaging, including near-infrared fluorescence imaging (NIRFI), magnetic resonance imaging (MRI), and photoacoustic imaging (PAI). Most importantly, without noticeable dark toxicity, the obtained Fe₃O₄@PB@PDA/AlPc/BSA nanocomposites are able to significantly suppress tumor growth via combined photothermal and photodynamic therapies upon a single 660 nm laser irradiation, achieving a superior synergetic manner compared to monotherapy both in vitro and in vivo. Therefore, our strategy provides Fe₃O₄@PB@PDA/AlPc/BSA nanocomposites for trimodality cancer imaging-guided synergistic therapy, with a great potential for new generation theranostics nanoagents.

Redox-active nanomaterials for nanomedicine applications

Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of reactive oxygen species. Conversely, several nanomaterials have also been shown to promote the generation of reactive oxygen species, which may precipitate the onset of oxidative stress, a state that is thought to contribute to the development of a variety of adverse conditions. As such, the impacts of nanomaterials on biological entities are often associated with and influenced by their specific redox properties. In this review, we overview several classes of nanomaterials that have been or projected to be used across a wide range of biomedical applications, with discussion focusing on their unique redox properties. Nanomaterials examined include iron, cerium, and titanium metal oxide nanoparticles, gold, silver, and selenium nanoparticles, and various nanoscale carbon allotropes such as graphene, carbon nanotubes, fullerenes, and their derivatives/variations. Principal topics of discussion include the chemical mechanisms by which the nanomaterials directly interact with biological entities and the biological cascades that are thus indirectly impacted. Selected case studies highlighting the redox properties of nanomaterials and how they affect biological responses are used to exemplify the biologically-relevant redox mechanisms for each of the described nanomaterials.

Carbon nanomaterials in oncology: an expanding horizon

Carbon nanomaterials have been attracting attention in oncology for the development of safe and effective cancer nanomedicines in increasing improved patient compliance for generally recognized as safe (GRAS) prominence. Toxicity, safety and efficacy of carbon nanomaterials are the major concerns in cancer theranostics. Various parameters such as particle size and shape or surface morphology, surface charge, composition, oxidation and nonoxidative-stress-related mechanisms are prone to toxicity of the carbon nanomaterials. Currently, few cancer-related products have been available on the market, although some are underway in preclinical and clinical phases. Thus, our main aim is to provide comprehensive details on the carbon nanomaterials in oncology from the past two decades for patient compliance and safety.

Structure, Properties, Functionalization, and Applications of Carbon Nanohorns

Carbon nanohorns (sometimes also known as nanocones) are conical carbon nanostructures constructed from an sp(2) carbon sheet. Nanohorns require no metal catalyst in their synthesis, and can be produced in industrial quantities. They provide a realistic and useful alternative to carbon nanotubes, and possibly graphene, in a wide range of applications. They also have their own unique behavior due to their specific conical morphology. However, their research and development has been slowed by several factors, notably during synthesis, they aggregate into spherical clusters ∼100 nm in diameter, blocking functionalization and treatment of individual nanocones. This limitation has recently been overcome with a new approach to separating these "dahlia-like" clusters into individual nanocones. In this review, we describe the structure, synthesis, and topology of carbon nanohorns, and provide a detailed review of nanohorn chemistry.

[3 + 2] cycloaddition reaction of azomethine ylides generated by thermal ring opening of aziridines onto carbon nanohorns

Functionalization of carbon nanohorns via [3 + 2] cycloaddition of azomethine ylides generated by thermal ring opening of aziridines.

Overcoming multidrug resistance by a combination of chemotherapy and photothermal therapy mediated by carbon nanohorns

A targeted drug delivery system based on carbon nanohorns for targeting P-glycoprotein and delivering etoposide into cells to overcome multidrug resistance.

One-step preparation of a water-soluble carbon nanohorn/phthalocyanine hybrid for dual-modality photothermal and photodynamic therapy

The biomedical applications of carbon nanomaterials, especially integrating noninvasive photothermal therapy (PTT) and photodynamic therapy (PDT), into a single system have enormous potential in cancer therapy. Herein, we present a novel and facile one-step method for the preparation of water-soluble single-walled carbon nanohorns (SWNHs) and metal phthalocyanines (MPc) hybrid for PTT and PDT. The hydrophilic MPc, tetrasulfonic acid tetrasodium salt copper phthalocyanine (TSCuPc), is coated on the surface of SWNHs via noncovalent π-π interaction using the sonication method. In this PTT/PDT nanosystem, SWNHs acts as a photosensitizer carrier and PTT agent, while TSCuPc acts as a hydrophilic and PDT agent. The EPR results demonstrated that the generated reactive oxygen species (ROS) not only from the photoinduced electron transfer process from TSCuPc to SWNHs but also from SWNHs without exciting TSCuPc to its excited state. The test of photothermal conversion proved that not only do SWNHs contribute to the photothermal therapy (PTT) effect, TSCuPc probably also contributes to that when it coats on the surface of SWNHs upon exposure to a 650-nm laser. More importantly, the results of in vitro cell viability revealed a significantly enhanced anticancer efficacy of combined noninvasive PTT/PDT, indicating that the SWNHs-TSCuPc nanohybrid is a hopeful candidate material for developing an efficient and biocompatible nanoplatform for biomedical application.

Graphene loading water-soluble phthalocyanine for dual-modality photothermal/photodynamic therapy via a one-step method

In this paper, we present a new and facile one-step method for the fabrication of a water-soluble graphene-phthalocyanine (GR–Pc) hybrid material by simply sonicating GR with a hydrophilic Pc, tetrasulfonic acid tetrasodium salt copper phthalocyanine (TSCuPc).

Single-walled carbon nanohorns and their applications

Single-walled carbon nanohorns (SWCNHs) are horn-shaped single-walled tubules with a conical tip. They are generally synthesized by laser ablation of pure graphite without using metal catalyst with high production rate and high yield, and typically form radial aggregates. SWCNHs are essentially metal-free and very pure, which avoids cumbersome purification and makes them user-friendly and environmentally benign. Currently, SWCNHs have been widely studied for various applications, such as gas storage, adsorption, catalyst support, drug delivery system, magnetic resonance analysis, electrochemistry, biosensing application, photovoltaics and photoelectrochemical cells, photodynamic therapy, fuel cells, and so on. This review outlines the research progress on SWCNHs, including their properties, functionalization, applications, and outlook.