Multifunctional nano-sized fullerenes for advanced tumor therapy

Carbon-Based Nanostructures as Emerging Materials for Gene Delivery Applications

Gene therapeutics are promising for treating diseases at the genetic level, with some already validated for clinical use. Recently, nanostructures have emerged for the targeted delivery of genetic material. Nanomaterials, exhibiting advantageous properties such as a high surface-to-volume ratio, biocompatibility, facile functionalization, substantial loading capacity, and tunable physicochemical characteristics, are recognized as non-viral vectors in gene therapy applications. Despite progress, current non-viral vectors exhibit notably low gene delivery efficiency. Progress in nanotechnology is essential to overcome extracellular and intracellular barriers in gene delivery. Specific nanostructures such as carbon nanotubes (CNTs), carbon quantum dots (CQDs), nanodiamonds (NDs), and similar carbon-based structures can accommodate diverse genetic materials such as plasmid DNA (pDNA), messenger RNA (mRNA), small interference RNA (siRNA), micro RNA (miRNA), and antisense oligonucleotides (AONs). To address challenges such as high toxicity and low transfection efficiency, advancements in the features of carbon-based nanostructures (CBNs) are imperative. This overview delves into three types of CBNs employed as vectors in drug/gene delivery systems, encompassing their synthesis methods, properties, and biomedical applications. Ultimately, we present insights into the opportunities and challenges within the captivating realm of gene delivery using CBNs.

Responsive Nanostructure for Targeted Drug Delivery

Currently, intelligent, responsive biomaterials have been widely explored, considering the fact that responsive biomaterials provide controlled and predictable results in various biomedical systems. Responsive nanostructures undergo reversible or irreversible changes in the presence of a stimulus, and that stimuli can be temperature, a magnetic field, ultrasound, pH, humidity, pressure, light, electric field, etc. Different types of stimuli being used in drug delivery shall be explained here. Recent research progress in the design, development and applications of biomaterials comprising responsive nanostructures is also described here. More emphasis will be given on the various nanostructures explored for the smart stimuli responsive drug delivery at the target site such as wound healing, cancer therapy, inflammation, and pain management in order to achieve the improved efficacy and sustainability with the lowest side effects. However, it is still a big challenge to develop well-defined responsive nanostructures with ordered output; thus, challenges faced during the design and development of these nanostructures shall also be included in this article. Clinical perspectives and applicability of the responsive nanostructures in the targeted drug delivery shall be discussed here.

Carbon nanostructures: a comprehensive review of potential applications and toxic effects

There is no doubt that nanotechnology has revolutionized our life since the 1970s when it was first introduced. Nanomaterials have helped us to improve the current products and services we use. Among the different types of nanomaterials, the application of carbon-based nanomaterials in every aspect of our lives has rapidly grown over recent decades. This review discusses recent advances of those applications in distinct categories, including medical, industrial, and environmental applications. The first main section introduces nanomaterials, especially carbon-based nanomaterials. In the first section, we discussed medical applications, including medical biosensors, drug and gene delivery, cell and tissue labeling and imaging, tissue engineering, and the fight against bacterial and fungal infections. The next section discusses industrial applications, including agriculture, plastic, electronic, energy, and food industries. In addition, the environmental applications, including detection of air and water pollutions and removal of environmental pollutants, were vastly reviewed in the last section. In the conclusion section, we discussed challenges and future perspectives.

Nanocarrier-Based Tumor-Targeting Drug Delivery Systems for Hepatocellular Carcinoma Treatments: Enhanced Therapeutic Efficacy and Reduced Drug Toxicity

Hepatocellular carcinoma (HCC), due to the lack of efficient diagnostic methods and short of available treatments, becomes the third main cause of cancer deaths. Novel treatments for HCCs are thus in great need. The fast-growing area of drug delivery provides intriguing possibility to design nanocarriers with unique properties. The nanocarriers performanced as drug deliver vehicles enable the design of diverse drug delivery systems, which could serve multiple purposes, including improved bioavailability, controlled or triggered release and targeted delivery, leading to enhanced drug efficacy and lowered drug toxicity. This paper provides an overview on the types of delivery vehicles, functions of drug nanocarriers and types of ligand-based targeting systems and highlights the advances made towards better HCC treatments.

Carbon nanomaterials as emerging nanotherapeutic platforms to tackle the rising tide of cancer - A review

Cancer has become one of the main reasons for human death in recent years. Around 18 million new cancer cases and approximately 9.6 million deaths from cancer reported in 2018, and the annual number of cancer cases will have increased to 22 million in the next two decades. These alarming facts have rekindled researchers' attention to develop and apply different approaches for cancer therapy. Unfortunately, most of the applied methods for cancer therapy not only have adverse side effects like toxicity and damage of healthy cells but also have a short lifetime. To this end, introducing innovative and effective methods for cancer therapy is vital and necessary. Among different potential materials, carbon nanomaterials can cope with the rising threats of cancer. Due to unique physicochemical properties of different carbon nanomaterials including carbon, fullerene, carbon dots, graphite, single-walled carbon nanotube and multi-walled carbon nanotubes, they exhibit possibilities to address the drawbacks for cancer therapy. Carbon nanomaterials are prodigious materials due to their ability in drug delivery or remedial of small molecules. Functionalization of carbon nanomaterials can improve the cancer therapy process and decrement the side effects. These exceptional traits make carbon nanomaterials as versatile and prevalent materials for application in cancer therapy. This article spotlights the recent findings in cancer therapy using carbon nanomaterials (2015-till now). Different types of carbon nanomaterials and their utilization in cancer therapy were highlighted. The plausible mechanisms for the action of carbon nanomaterials in cancer therapy were elucidated and the advantages and disadvantages of each material were also illustrated. Finally, the current problems and future challenges for cancer therapy based on carbon nanomaterials were discussed.

Fullerene translocation through peroxidized lipid membranes

Recent cytotoxicity research suggests that fullerenes can enter the cell and cross the blood-brain barrier. However, the underlying toxicity mechanism behind the penetration of fullerenes through biological membranes is still not well understood. Here we perform coarse-grained molecular dynamics simulations to investigate the interactions of fullerenes and their polar derivatives (Janus) with model regular and peroxidized bilayers. We show that the translocation of fullerenes and their residence time in bulk water vary depending on the bilayer's peroxidation degree and fullerene polarity. The distribution of fullerenes inside the bilayer is mainly determined by the peroxidation degree and the saturation level of lipid acyl chains. The transport of pristine fullerenes through bilayers occurs at nano timescale while the complete diffusion may not be achieved for Janus fullerenes in micro timescale. As for the toxic response of fullerenes in terms of membrane damage, no mechanical disruption of model bilayers is observed throughout the studied simulation times.

Cyclic RGD-Conjugated Hyaluronate Dot Bearing Cleavable Doxorubicin for Multivalent Tumor Targeting

In this study, we developed an extremely small-sized water-soluble hyaluronate dot (dHA) conjugated with cyclic RGD (cRGD) and cleavable doxorubicin (DOX, as a model antitumor drug), named cRGD@dHA-c-DOX. This dot with HA moieties (as specific ligands to tumor CD44 receptors) and cRGD moieties (as specific ligands to tumor integrin α_vβ₃) was designed to enable multivalent tumor targeting. In particular, the imine bonds, linking the DOX and dHA, can exhibit cleavage performance at endosomal pH, resulting in pH-triggered DOX release from cRGD@dHA-c-DOX. We demonstrated that cRGD@dHA-c-DOX resulted in highly improved cellular uptake and cell death in MDA-MB-231 tumor cells (CD44+, integrin α_vβ₃+) compared to those in Huh7 tumor cells (CD44-, integrin α_vβ₃-). In vivo studies using MDA-MB-231 tumor-bearing mice revealed that cRGD@dHA-c-DOX enhanced the tumor inhibition efficacy. These results suggest that cRGD@dHA-c-DOX can be utilized as a promising multivalent tumor-targeting drug carrier for highly efficient tumor treatment.

PEG-modified aziridines for stereoselective synthesis of water-soluble fulleropyrrolidines

Diastereoselective synthesis of water-soluble fullerene compounds bearing a pharmacophore pyrrolofullerene-2',5'-dicarboxylate unit is reported. The stereocontrol of the product configuration is achieved through stereospecificity of two consecutive concerted reactions: electrocyclic aziridine ring opening followed by 1,3-dipolar cycloaddition of the resulting azomethyne ylide. The solubility in water (up to 20 μM through direct dissolution) is secured by introducing a polyethylene glycol (PEG) hydrophilic pendant. The structure and molecular-mass distribution of the resulting PEGylated fulleropyrrolidines are exhaustively characterized by 1H, 13C NMR and HRMS. According to absorbance spectroscopy, AFM and DLS studies, the synthesized compound tends to aggregate in aqueous media forming associates of ca. 4-9 nm radius surrounded by a solvation shell resulting in an effective hydrodynamic diameter of ca. 90 nm. In view of notable solubility in water, well-defined chemical structure and resemblance to the compounds with known anti-HIV activity, the synthesized PEGylated diethyl trans-pyrrolofullerene-2',5'-dicarboxylate might be an attractive candidate for biological evaluation.

Recent Progress in the Development of Poly(lactic-co-glycolic acid)-Based Nanostructures for Cancer Imaging and Therapy

Diverse nanosystems for use in cancer imaging and therapy have been designed and their clinical applications have been assessed. Among a variety of materials available to fabricate nanosystems, poly(lactic-co-glycolic acid) (PLGA) has been widely used due to its biocompatibility and biodegradability. In order to provide tumor-targeting and diagnostic properties, PLGA or PLGA nanoparticles (NPs) can be modified with other functional materials. Hydrophobic or hydrophilic therapeutic cargos can be placed in the internal space or adsorbed onto the surface of PLGA NPs. Protocols for the fabrication of PLGA-based NPs for cancer imaging and therapy are already well established. Moreover, the biocompatibility and biodegradability of PLGA may elevate its feasibility for clinical application in injection formulations. Size-controlled NP’s properties and ligand–receptor interactions may provide passive and active tumor-targeting abilities, respectively, after intravenous administration. Additionally, the introduction of several imaging modalities to PLGA-based NPs can enable drug delivery guided by in vivo imaging. Versatile platform technology of PLGA-based NPs can be applied to the delivery of small chemicals, peptides, proteins, and nucleic acids for use in cancer therapy. This review describes recent findings and insights into the development of tumor-targeted PLGA-based NPs for use of cancer imaging and therapy.

Fullerene-based delivery systems

With the development of new drugs, there have been many attempts to explore innovative delivery routes. Targeted delivery systems are a desired solution designed to overcome the deficiency of routine methods. To transform this idea into reality, a wide range of nanoparticles has been proposed and studied. These nanoparticles should interact well with biological environments and pass through cell membranes to deliver therapeutic molecules. One of the pioneer classes of carbon-based nanoparticles for targeted delivery is the fullerenes. Fullerenes have a unique structure and possess suitable properties for interaction with the cellular environment. This short review concentrates on newly developed fullerene derivatives and their potential as advanced delivery systems for pharmaceutical applications.

Augmented tumor accumulation and photothermal ablation using gold nanoparticles with a particular cellular entry orientation

Gold nanoparticles with various functionalities have served as potential tools in nanotechnology for tumor ablation. In this work, we seek to design and develop gold nanoparticle with poly(ethylene glycol)-containing dopamine (hereafter termed as AuND), and to synthesize the AuND with one-sided Tat peptide expression (OT@AuND). We demonstrate the tumor cell-targeting ability on the basis of anti-nonspecific cell binding of OT@AuND and determine how the chemically modified gold nanoparticle–based product affects photothermal tumor therapy in vitro and in vivo. The OT@AuND with a particular cellular entry orientation–induced delayed endocytosis, which is advantageous for enhanced permeability and retention effect-based tumor accumulation. This is because the slower cellular interaction of OT@AuND allows it to have the time to be transported to and bind to the tumor site. In tumor cell lines, OT@AuND showed a lower cellular uptake than gold nanoparticles with full-sided Tat peptide expression (FT@AuND) in the early period (after its in vitro and in vivo administration), but the cellular internalization rate of OT@AuND caught up with that of FT@AuND in the late period. Importantly, the delayed cellular internalization feature of OT@AuND resulted in efficient tumor accumulation in tumor-bearing mice, because the time interval provided OT@AuND more chances not to bind to any cells, but to enter tumor cells, leading to selective photothermal tumor ablation. These data suggest that gold nanoparticles with a particular cellular entry orientation can be further explored as a potential photothermal therapeutic agent and as a strategy to treat tumors.

Multifunctional trastuzumab-chlorin e6 conjugate for the treatment of HER2-positive human breast cancer

Effective penetration and targeted delivery of anticancer drugs into tumor tissues are limiting factors for achieving enhanced therapeutic efficacy. In order to overcome the disadvantages of antibody therapy (limited penetration efficacy into tumor tissues) and photodynamic therapy (low targeting efficiency) on the treatment of HER2-positive human breast cancer simultaneously, an antibody and photosensitizer combined Trastuzumab-chlorin e6 conjugate (TMPC) was synthesized. TMPC exhibits high singlet oxygen generation under laser irradiation. In vitro data show that TMPC has specific HER2 selective interactions, and ROS generation ability upon laser irradiation induces significant cell death in HER2-positive breast cancer cells. The enhanced tissue penetration ability and tissue access of TMPC resulting from local tissue destruction by ROS generated from Ce6 is also demonstrated in breast cancer tissue blocks. The enhanced ability of TMPC is supported by in vivo fluorescence images of SK-BR-3 (HER2-positive cancer cells) tumor-bearing mice. The in vivo test demonstrates approximately 6-fold enhanced accumulation of TMPC in xenograft tumors with a longer retention time compared to that of the PEG-Ce6 conjugate at 24 h. Thus, trastuzumab and photosensitizer conjugation brings synergistic effects for HER2 selective targeting, where TMPC enhanced tumor tissue penetration improves tumor tissue access and responsiveness of trastuzumab in HER2 overexpressing breast cancer.

Carbon Nanomaterials for Targeted Cancer Therapy Drugs: A Critical Review

Cancer represents one of the main causes of human death in developed countries. Most current therapies, unfortunately, carry a number of side effects, such as toxicity and damage to healthy cells, as well as the risk of resistance and recurrence. Therefore, cancer research is trying to develop therapeutic procedures with minimal negative consequences. The use of nanomaterial-based systems appears to be one of them. In recent years, great progress has been made in the field using nanomaterials with high potential in biomedical applications. Carbon nanomaterials, thanks to their unique physicochemical properties, are gaining more and more popularity in cancer therapy. They are valued especially for their ability to deliver drugs or small therapeutic molecules to these cells. Through surface functionalization, they can specifically target tumor tissues, increasing the therapeutic potential and significantly reducing the adverse effects of therapy. Their potential future use could, therefore, be as vehicles for drug delivery. This review presents the latest findings of research studies using carbon nanomaterials in the treatment of various types of cancer. To carry out this study, different databases such as Web of Science, PubMed, MEDLINE and Google Scholar were employed. The findings of research studies chosen from more than 2000 viewed scientific publications from the last 15 years were compared.

pH-Responsive hyaluronated liposomes for docetaxel delivery

In this study, we report pH-responsive liposomes consisting of hydrogenated soy phosphatidylcholine (HSPC) as a lipid, hyaluronic acid (HA) grafted with functional 3-diethylaminopropyl (DEAP) groups (hereafter denoted as HA-g-DEAP) as a pH-responsive polymer, and docetaxel (DTX) as an antitumor drug. DTX-loaded HSPC liposomes were prepared via a conventional liposome manufacturing procedure and then were decorated with HA-g-DEAP (HA-g-DEAP0.15, HA-g-DEAP0.25, and HA-g-DEAP0.40, according to the molar conjugate ratio of DEAP to HA) in an aqueous solution (pH 7.4), by sonication. The liposomes with HA-g-DEAP0.40 allowed the efficient release of the encapsulated DTX content when the pH of the solution decreased to 6.5 (i.e., endosomal pH), owing to the acidic pH-induced protonation of the DEAP anchored to the vesicular lipid bilayers. These hyaluronated liposomes were effective at entering the human colon carcinoma HCT-116 cells with a CD44 receptor overexpression. In an in vitro tumor cell cytotoxicity test, the DTX-loaded liposomes caused a significant increase in HCT-116 tumor cell death, revealing their pharmaceutical potential in tumor therapy.

Carbon-based hybrid nanogels: a synergistic nanoplatform for combined biosensing, bioimaging, and responsive drug delivery

Nanosized crosslinked polymer networks, named as nanogels, are playing an increasingly important role in a diverse range of applications by virtue of their porous structures, large surface area, good biocompatibility and responsiveness to internal and/or external chemico-physical stimuli. Recently, a variety of carbon nanomaterials, such as carbon quantum dots, graphene/graphene oxide nanosheets, fullerenes, carbon nanotubes, and nanodiamonds, have been embedded into responsive polymer nanogels, in order to integrate the unique electro-optical properties of carbon nanomaterials with the merits of nanogels into a single hybrid nanogel system for improvement of their applications in nanomedicine. A vast number of studies have been pursued to explore the applications of carbon-based hybrid nanogels in biomedical areas for biosensing, bioimaging, and smart drug carriers with combinatorial therapies and/or theranostic ability. New synthetic methods and structures have been developed to prepare carbon-based hybrid nanogels with versatile properties and functions. In this review, we summarize the latest developments and applications and address the future perspectives of these carbon-based hybrid nanogels in the biomedical field.

Hyaluronate dots for highly efficient photodynamic therapy

Nanoscale particles, such as quantum dots and carbon dots, are important materials for use in sensing and treating irregular biological events, but their versatility for biomedical applications are usually limited by their undesirable properties such toxicity and non-degradability. Here, we report biofunctional hyaluronic acid (HA) dots containing biodegradable/biocompatible HA. HA dots were prepared by conjugating multiple HA molecules to C₆₀ (used as a base dot) without any hydrothermal treatment. The hydroxyl groups of HA completely linked to all π-π carbon bonds in C₆₀. The chemically synthesized HA dots (Mn=16.1kDa) were 2nm in diameter, soluble in aqueous solution, and possessed multiple functional (carboxyl) groups. The HA dots were biofunctional, enabling highly efficient binding to CD44 receptors overexpressed on in vitro/in vivo tumors. With light illumination, we demonstrated that the HA dots bearing a photosensitizing model drug (chlorin e6: Ce6) resulted in a significant enhancement in in vitro/in vivo tumor cell ablation. We believe that this approach offers a new strategy to create biopolymer dots.

Mechanistic applications of click chemistry for pharmaceutical drug discovery and drug delivery

The concept of click chemistry (CC), first introduced by K.B. Sharpless, has been widely adopted for use in drug discovery, novel drug delivery systems (DDS), polymer chemistry, and material sciences. In this review, we outline novel aspects of CC related to drug discovery and drug delivery, with a brief overview of molecular mechanisms underlying each click reaction commonly used by researchers, and the main patents that paved the way for further diverse medicinal applications. We also describe recent progress in drug discovery and polymeric and carbon material-based drug delivery for potential pharmaceutical applications and advancements based on the CC approach, and discuss some intrinsic limitations of this popular conjugation reaction. The use of CC is likely to significantly advance drug discovery and bioconjugation development.

Bacteriomimetic poly-γ-glutamic acid surface coating for hemocompatibility and safety of nanomaterials

Poly-γ-glutamic acid (PGA), a major component of the bacterial capsule, is known to confer hydrophilicity to bacterial surfaces and protect bacteria from interactions with blood cells. We tested whether applying a bacteriomimetic surface coating of PGA modulates interactions of nanomaterials with blood cells or affects their safety and photothermal antitumor efficacy. Amphiphilic PGA (APGA), prepared by grafting phenylalanine residues to PGA, was used to anchor PGA to reduced graphene oxide (rGO) nanosheets, a model of hydrophobic nanomaterials. Surface coating of rGO with bacterial capsule-like APGA yielded APGA-tethered rGO nanosheets (ArGO). ArGO nanosheets remained stable in serum over 4 weeks, whereas rGO in plain form precipitated in serum within 5 minutes. Moreover, ArGO did not interact with blood cells, whereas rGO in plain form or as a physical mixture with PGA formed aggregates with blood cells. Mice administered ArGO at a dose of 50 mg/kg showed 100% survival and no hepatic or renal toxicity. No mice survived exposure at the same dose of rGO or a PGA/rGO mixture. Following intravenous administration, ArGO showed a greater distribution to tumors and prolonged tumor retention compared with other nanosheet formulations. Irradiation with near-infrared light completely ablated tumors in mice treated with ArGO. Our results indicate that a bacteriomimetic surface modification of nanomaterials with bacterial capsule-like APGA improves the stability in blood, biocompatibility, tumor distribution, and photothermal antitumor efficacy of rGO. Although APGA was used here to coat the surfaces of rGO, it could be applicable to coat surfaces of other hydrophobic nanomaterials.