Targeted killing of cancer cells in vivo and in vitro with IGF-IR antibody-directed carbon nanohorns based drug delivery

Carbon Nanomaterials (CNMs) in Cancer Therapy: A Database of CNM-Based Nanocarrier Systems

Carbon nanomaterials (CNMs) are an incredibly versatile class of materials that can be used as scaffolds to construct anticancer nanocarrier systems. The ease of chemical functionalisation, biocompatibility, and intrinsic therapeutic capabilities of many of these nanoparticles can be leveraged to design effective anticancer systems. This article is the first comprehensive review of CNM-based nanocarrier systems that incorporate approved chemotherapy drugs, and many different types of CNMs and chemotherapy agents are discussed. Almost 200 examples of these nanocarrier systems have been analysed and compiled into a database. The entries are organised by anticancer drug type, and the composition, drug loading/release metrics, and experimental results from these systems have been compiled. Our analysis reveals graphene, and particularly graphene oxide (GO), as the most frequently employed CNM, with carbon nanotubes and carbon dots following in popularity. Moreover, the database encompasses various chemotherapeutic agents, with antimicrotubule agents being the most common payload due to their compatibility with CNM surfaces. The benefits of the identified systems are discussed, and the factors affecting their efficacy are detailed.

Multifunctional theranostic nanoparticles for biomedical cancer treatments - A comprehensive review

Modern-day search for the novel agents (their preparation and consequent implementation) to effectively treat the cancer is mainly fuelled by the historical failure of the conventional treatment modalities. Apart from that, the complexities such as higher rate of cell mutations, variable tumor microenvironment, patient-specific disparities, and the evolving nature of cancers have made this search much stronger in the latest times. As a result of this, in about two decades, the theranostic nanoparticles (TNPs) - i.e., nanoparticles that integrate therapeutic and diagnostic characteristics - have been developed. The examples for TNPs include mesoporous silica nanoparticles, luminescence nanoparticles, carbon-based nanomaterials, metal nanoparticles, and magnetic nanoparticles. These TNPs have emerged as single and powerful cancer-treating multifunctional nanoplatforms, as they widely provide the necessary functionalities to overcome the previous/conventional limitations including lack of the site-specific delivery of anti-cancer drugs, and real-time continuous monitoring of the target cancer sites while performing therapeutic actions. This has been mainly possible due to the association of the as-developed TNPs with the already-available unique diagnostic (e.g., luminescence, photoacoustic, and magnetic resonance imaging) and therapeutic (e.g., photothermal, photodynamic, hyperthermia therapy) modalities in the biomedical field. In this review, we have discussed in detail about the recent developments on the aforementioned important TNPs without/with targeting ability (i.e., attaching them with ligands or tumor-specific antibodies) and also the strategies that are implemented to increase their tumor accumulation and to enhance their theranostic efficacies for effective biomedical cancer treatments.

Carbon Nanohorns as Effective Nanotherapeutics in Cancer Therapy

Different carbon nanostructures have been explored as functional materials for the development of effective nanomaterials in cancer treatment applications. This review mainly aims to discuss the features, either strength or weakness, of carbon nanohorn (CNH), carbon conical horn-shaped nanostructures of sp2 carbon atoms. The interest for these materials arises from their ability to couple the clinically relevant properties of carbon nanomaterials as drug carriers with the negligible toxicity described in vivo. Here, we offer a comprehensive overview of the recent advances in the use of CNH in cancer treatments, underlining the benefits of each functionalization route and approach, as well as the biological performances of either loaded and unloaded materials, while discussing the importance of delivery devices.

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.

UCNP-based Photoluminescent Nanomedicines for Targeted Imaging and Theranostics of Cancer

Theranostic approach is currently among the fastest growing trends in cancer treatment. It implies the creation of multifunctional agents for simultaneous precise diagnosis and targeted impact on tumor cells. A new type of theranostic complexes was created based on NaYF₄: Yb,Tm upconversion nanoparticles coated with polyethylene glycol and functionalized with the HER2-specific recombinant targeted toxin DARPin-LoPE. The obtained agents bind to HER2-overexpressing human breast adenocarcinoma cells and demonstrate selective cytotoxicity against this type of cancer cells. Using fluorescent human breast adenocarcinoma xenograft models, the possibility of intravital visualization of the UCNP-based complexes biodistribution and accumulation in tumor was demonstrated.

Single-Walled Carbon Nanohorns as Promising Nanotube-Derived Delivery Systems to Treat Cancer

Cancer has become one of the most prevalent diseases worldwide, with increasing incidence in recent years. Current pharmacological strategies are not tissue-specific therapies, which hampers their efficacy and results in toxicity in healthy organs. Carbon-based nanomaterials have emerged as promising nanoplatforms for the development of targeted delivery systems to treat diseased cells. Single-walled carbon nanohorns (SWCNH) are graphene-based horn-shaped nanostructure aggregates with a multitude of versatile features to be considered as suitable nanosystems for targeted drug delivery. They can be easily synthetized and functionalized to acquire the desired physicochemical characteristics, and no toxicological effects have been reported in vivo followed by their administration. This review focuses on the use of SWCNH as drug delivery systems for cancer therapy. Their main applications include their capacity to act as anticancer agents, their use as drug delivery systems for chemotherapeutics, photothermal and photodynamic therapy, gene therapy, and immunosensing. The structure, synthesis, and covalent and non-covalent functionalization of these nanoparticles is also discussed. Although SWCNH are in early preclinical research yet, these nanotube-derived nanostructures demonstrate an interesting versatility pointing them out as promising forthcoming drug delivery systems to target and treat cancer cells.

Nanotechnology for angiogenesis: opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses.

When polymers meet carbon nanostructures: expanding horizons in cancer therapy

The development of hybrid materials, which combine inorganic with organic materials, is receiving increasing attention by researchers. As a consequence of carbon nanostructures high chemical versatility, they exhibit enormous potential for new highly engineered multifunctional nanotherapeutic agents for cancer therapy. Whereas many groups are working on drug delivery systems for chemotherapy, the use of carbon nanohybrids for radiotherapy is rarely applied. Thus, nanotechnology offers a wide range of solutions to overcome the current obstacles of conventional chemo- and/or radiotherapies. Within this review, the structure and properties of carbon nanostructures (carbon nanotubes, nanographene oxide) functionalized preferentially with different types of polymers (synthetic, natural) are discussed. In short, synthesis approaches, toxicity investigations and anticancer efficacy of different carbon nanohybrids are described.

Biodistribution Survey of Oxidized Single-Wall Carbon Nanohorns Following Different Administration Routes by Using Label-Free Multispectral Optoacoustic Tomography

Introduction

Though widely studied for biomedical applications, the lack of current systemic studies on the in vivo fate of single-walled carbon nanohorns (SWCNHs) largely restricts their further applications, as real-time monitoring of their biodistribution remains a big challenge. Here, we aim to customize a label-free multispectral optoacoustic tomography (MSOT) method and systematically survey the fate of oxidized SWCNHs (SWCNHox) following different exposure routes by whole body imaging.

Methods

Mice were given a suspension of SWCNHox with an average size of 136.4 nm via four different administration routes, and then imaged by MSOT.

Results

After oral gavage, SWCNHox were mainly distributed in the gastrointestinal tract then excreted through the gut. Compared with the observation post first dosing, the accumulation of SWCNHox in the gastrointestinal tract was not obvious even after four-time oral gavage. Almost no SWCNHox were found at detectable levels in kidney, liver, blood and spleen. Following intravenous (iv) injection, SWCNHox were mainly presented and persisted in the spleen and liver, while very little in the kidney and almost none detectable in the intestine. SWCNHox accumulated significantly in the liver and spleen after four IV administrations. Following hypodermic and intramuscular injections, almost no SWCNHox could cross biological barriers and transport to the spleen, kidney or liver, likely due to their very low absorption rate. Almost all SWCNHox remained around the injection sites. For the first time, we have systematically investigated the in vivo fate of SWCNHs in a label-free and real-time manner.

Conclusion

The findings of this study provide insights into the selection of appropriate exposure routes for potential biomedical applications of carbon nanomaterials.

Surface engineering of nanomaterials with phospholipid-polyethylene glycol-derived functional conjugates for molecular imaging and targeted therapy

In recent years, phospholipid-polyethylene glycol-derived functional conjugates have been widely employed to decorate different nanomaterials, due to their excellent biocompatibility, long blood circulation characteristics, and specific targeting capability. Numerous in vivo studies have demonstrated that nanomedicines peripherally engineered with phospholipid-polyethylene glycol-derived functional conjugates show significantly increased selective and efficient internalization by target cells/tissues. Targeting moieties including small-molecule ligands, peptides, proteins, and antibodies are generally conjugated onto PEGylated phospholipids to decorate liposomes, micelles, hybrid nanoparticles, nanocomplexes, and nanoemulsions for targeted delivery of diagnostic and therapeutic agents to diseased sites. In this review, the synthesis methods of phospholipid-polyethylene glycol-derived functional conjugates, biophysicochemical properties of nanomedicines decorated with these conjugates, factors dominating their targeting efficiency, as well as their applications for in vivo molecular imaging and targeted therapy were summarized and discussed.

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.

Herceptin-conjugated paclitaxel loaded PCL-PEG worm-like nanocrystal micelles for the combinatorial treatment of HER2-positive breast cancer

We have constructed Herceptin-conjugated, paclitaxel (PTX) loaded, PCL-PEG worm-like nanocrystal micelles (PTX@PCL-PEG-Herceptin) for the combinatorial therapy of HER2-positive breast cancer that exploit the specific targeting of Herceptin to HER2-positive breast cancer cells. Firstly, amphiphilic PCL₂₀₀₀-MPEG₂₀₀₀ and PCL₅₀₀₀-PEG₂₀₀₀-CHO were selected as the optimized matrix to wrap PTX that self-assembled into worm-like micelles with internal nanocrystal structures (PTX@PCL-PEG). Then the aldehydes of PCL₅₀₀₀-PEG₂₀₀₀-CHO exposed on the outside surface of PTX@PCL-PEG were utilized to react with the primary amines of Herceptin and formed stable, carbon-nitrogen single linkers (-C-N-) between the antibodies and nanoparticles. This study shows PTX@PCL-PEG-Herceptin remained relatively stable in the circulation and in the tumor microenvironment, and rapidly targeted and entered into the HER2-overexpressing tumor cells while sparing normal tissues from the toxic effects. PTX@PCL-PEG-Herceptin shrank the tumors and prolonged survival time in a SKBR-3-tumor-xenograft, nude mice model more effectively than TAXOL®, PTX@PCL-PEG, Herceptin+TAXOL® and Herceptin+PTX@PCL-PEG. Mechanistic studies showed that PTX@PCL-PEG-Herceptin entered into the HER2-positive tumor cells through the caveolin-mediated pathway. The conjugated Herceptin greatly enhanced the binding ability of the nanoparticle to the targeted SKBR-3 cells. This novel strategy provides a rational and simple antibody-conjugated-nanoparticle platform for the clinical application of combinatorial anticancer treatment.

Antibody immobilization technique using protein film for high stability and orientation control of the immobilized antibody

The development of antibody immobilization techniques is essential for creating antibody-based biomaterials. Although numerous methods for antibody immobilization have been demonstrated, low stability and disordered orientation of the immobilized antibody remain an important problem. In this work, an original antibody immobilization technique using a protein film, which achieved a high stability and orientation control of the immobilized antibody, has been described. In this method, an antibody-immobilized albumin film was prepared by adding the cross-linked albumin solution to the substrate, where antibodies were attached in uniform orientation, followed by subsequent drying, and detaching the formed film from the substrate by heating at 120 °C in a dry state. Antibodies in the film showed high antigen-binding capacity, at a level comparable to the oriented immobilized antibody using protein G. The stability of antibodies in the film was found to be significantly high; their antigen-binding capacity was completely retained even after storage at 40 °C in a dry state for one month. Thus, this approach provides useful information to immobilize the antibody on solid surfaces while controlling its orientation and increasing its stability.

Targeted Delivery to Tumors: Multidirectional Strategies to Improve Treatment Efficiency

Malignant tumors are characterized by structural and molecular peculiarities providing a possibility to directionally deliver antitumor drugs with minimal impact on healthy tissues and reduced side effects. Newly formed blood vessels in malignant lesions exhibit chaotic growth, disordered structure, irregular shape and diameter, protrusions, and blind ends, resulting in immature vasculature; the newly formed lymphatic vessels also have aberrant structure. Structural features of the tumor vasculature determine relatively easy penetration of large molecules as well as nanometer-sized particles through a blood⁻tissue barrier and their accumulation in a tumor tissue. Also, malignant cells have altered molecular profile due to significant changes in tumor cell metabolism at every level from the genome to metabolome. Recently, the tumor interaction with cells of immune system becomes the focus of particular attention, that among others findings resulted in extensive study of cells with preferential tropism to tumor. In this review we summarize the information on the diversity of currently existing approaches to targeted drug delivery to tumor, including (i) passive targeting based on the specific features of tumor vasculature, (ii) active targeting which implies a specific binding of the antitumor agent with its molecular target, and (iii) cell-mediated tumor targeting.

Targeted killing of prostate cancer cells using antibody-drug conjugated carbon nanohorns

The ability of carbon nanohorns (CNHs) to cross biological barriers makes them potential carriers for delivery purposes. In this work, we report the design of a new selective antibody-drug nanosystem based on CNHs for the treatment of prostate cancer (PCa). In particular, cisplatin in a prodrug form and the monoclonal antibody (Ab) D2B, selective for PSMA⁺ cancer cells, have been attached to CNHs due to the current application of this antigen in PCa therapy. The hybrids Ab-CNHs, cisplatin-CNHs and functionalised-CNHs have also been synthesized to be used as control systems. The efficacy and specificity of the D2B-cisplatin-CNH conjugate to selectively target and kill PSMA⁺ prostate cancer cells have been demonstrated in comparison with other derivatives. The developed strategy to functionalise CNHs is fascinating because it can allow the fine tuning of both drug and Ab molecules attached to the nanostructure in order to modulate the activity of the nanosystem. Finally, the herein described methodology can be used for the incorporation of almost any drugs or Abs in the platforms in order to create new targeted drugs for the treatment of different diseases.

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.

The interactions of single-wall carbon nanohorns with polar epithelium

Single-wall carbon nanohorns (SWCNHs), which have multitudes of horn interstices, an extensive surface area, and a spherical aggregate structure, offer many advantages over other carbon nanomaterials being used as a drug nanovector. The previous studies on the interaction between SWCNHs and cells have mostly emphasized on cellular uptake and intracellular trafficking, but seldom on epithelial cells. Polar epithelium as a typical biological barrier constitutes the prime obstacle for the transport of therapeutic agents to target site. This work tried to explore the permeability of SWCNHs through polar epithelium and their abilities to modulate transcellular transport, and evaluate the potential of SWCNHs in drug delivery. Madin-Darby canine kidney (MDCK) cell monolayer was used as a polar epithelial cell model, and as-grown SWCNHs, together with oxidized and fluorescein isothiocyanate-conjugated bovine serum albumin-labeled forms, were constructed and comprehensively investigated in vitro and in vivo. Various methods such as transmission electron microscopy and confocal imaging were used to visualize their intracellular uptake and localization, as well as to investigate the potential transcytotic process. The related mechanism was explored by specific inhibitors. Additionally, fast multispectral optoacoustic tomography imaging was used for monitoring the distribution and transport process of SWCNHs in vivo after oral administration in nude mice, as an evidence for their interaction with the intestinal epithelium. The results showed that SWCNHs had a strong bioadhesion property, and parts of them could be uptaken and transcytosed across the MDCK monolayer. Multiple mechanisms were involved in the uptake and transcytosis of SWCNHs with varying degrees. After oral administration, oxidized SWCNHs were distributed in the gastrointestinal tract and retained in the intestine for up to 36 h probably due to their surface adhesion and endocytosis into the intestinal epithelium. Overall, this comprehensive investigation demonstrated that SWCNHs can serve as a promising nanovector that can cross the barrier of polar epithelial cells and deliver drugs effectively.

Carbon Nanomaterials Interfacing with Neurons: An In vivo Perspective

Developing new tools that outperform current state of the art technologies for imaging, drug delivery or electrical sensing in neuronal tissues is one of the great challenges in neurosciences. Investigations into the potential use of carbon nanomaterials for such applications started about two decades ago. Since then, numerous in vitro studies have examined interactions between these nanomaterials and neurons, either by evaluating their compatibility, as vectors for drug delivery, or for their potential use in electric activity sensing and manipulation. The results obtained indicate that carbon nanomaterials may be suitable for medical therapies. However, a relatively small number of in vivo studies have been carried out to date. In order to facilitate the transformation of carbon nanomaterial into practical neurobiomedical applications, it is essential to identify and highlight in the existing literature the strengths and weakness that different carbon nanomaterials have displayed when probed in vivo. Unfortunately the current literature is sometimes sparse and confusing. To offer a clearer picture of the in vivo studies on carbon nanomaterials in the central nervous system, we provide a systematic and critical review. Hereby we identify properties and behavior of carbon nanomaterials in vivo inside the neural tissues, and we examine key achievements and potentially problematic toxicological issues.

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.

Nanoparticles for brain-specific drug and genetic material delivery, imaging and diagnosis

The poor access of therapeutic drugs and genetic material into the central nervous system due to the presence of the blood-brain barrier often limits the development of effective noninvasive treatments and diagnoses of neurological disorders. Moreover, the delivery of genetic material into neuronal cells remains a challenge because of the intrinsic difficulty in transfecting this cell type. Nanotechnology has arisen as a promising tool to provide solutions for this problem. This review will cover the different approaches that have been developed to deliver drugs and genetic material efficiently to the central nervous system as well as the main nanomaterials used to image the central nervous system and diagnose its disorders.

Enhancing the antitumor effect of methotrexate in intro and in vivo by a novel targeted single-walled carbon nanohorn-based drug delivery system

The present research reports a smart multifunctional oxidized single-wall carbon nanohorns (oxSWNHs) drug delivery system (DDS) which could enhance the anti-tumor effect of methotrexate (MTX).

Targeted and controlled release delivery of daunorubicin to T-cell acute lymphoblastic leukemia by aptamer-modified gold nanoparticles

Clinical administration of daunorubicin (Dau) in treatment of leukemia has been limited by its cardiotoxicity. Targeted delivery of chemotherapy drugs could reduce their side effects and increase the therapeutic efficacy of these drugs. Biocompatibility and large surface area of gold nanoparticles (AuNPs) make these nanoparticles great candidates for biomedical applications. In this study sgc8c aptamer (Apt)-Dau-AuNPs complex was designed and evaluated for treatment of Molt-4 cells (human acute lymphoblastic leukemia T-cell, target). Apt-Dau-AuNPs complex formation was analyzed by fluorometric analysis and gel retardation assay. Dau release profiles from the complex were evaluated in pHs 5.5 and 7.4. For cytotoxic studies (MTT assay) U266 (B lymphocyte human myeloma, nontarget) and Molt-4 cells (target) were treated with Dau Apt-Dau conjugate and Apt-Dau-AuNPs complex. Internalization was monitored by flow cytometry and confocal imaging. 12 μM Dau was efficiently loaded onto 1 mL of Apt-modified AuNPs. Dau was released from the complex in a pH-dependent manner (higher rate of release at pH 5.5). The results of flow cytometry analysis and confocal imaging showed that the complex was effectively internalized into Molt-4 cells, but not into U266 cells. The results of MTT assay also confirmed the internalization data. Apt-Dau-AuNPs complex was less cytotoxic in U266 cells compared to Dau alone and even Apt-Dau conjugate. The complex was more cytotoxic in target cells in comparison with Dau alone and even Apt-Dau conjugate. In conclusion, Apt-Dau-AuNPs complex was able to selectively target Molt-4 cells. Another advantage of this system was pH-dependent release of drug from the complex. Furthermore, this complex has characteristics which make it ideal for clinical use.