Functionalization of Carbon Nanomaterials for Biomedical Applications

Hierarchical Self-Assembly of Water-Soluble Fullerene Derivatives into Supramolecular Hydrogels

Controlling the self-assembly of nanoparticle building blocks into macroscale soft matter structures is an open question and of fundamental importance to fields as diverse as nanomedicine and next-generation energy storage. Within the vast library of nanoparticles, the fullerenes-a family of quasi-spherical carbon allotropes-are not explored beyond the most common, C60. Herein, a facile one-pot method is demonstrated for functionalizing fullerenes of different sizes (C60, C70, C84, and C90-92), yielding derivatives that self-assemble in aqueous solution into supramolecular hydrogels with distinct hierarchical structures. It is shown that the mechanical properties of these resultant structures vary drastically depending on the starting material. This work opens new avenues in the search for control of macroscale soft matter structures through tuning of nanoscale building blocks.

Application of Nanoparticles in Cancer Treatment: A Concise Review

Timely diagnosis and appropriate antitumoral treatments remain of utmost importance, since cancer remains a leading cause of death worldwide. Within this context, nanotechnology offers specific benefits in terms of cancer therapy by reducing its adverse effects and guiding drugs to selectively target cancer cells. In this comprehensive review, we have summarized the most relevant novel outcomes in the range of 2010-2023, covering the design and application of nanosystems for cancer therapy. We have established the general requirements for nanoparticles to be used in drug delivery and strategies for their uptake in tumor microenvironment and vasculature, including the reticuloendothelial system uptake and surface functionalization with protein corona. After a brief review of the classes of nanovectors, we have covered different classes of nanoparticles used in cancer therapies. First, the advances in the encapsulation of drugs (such as paclitaxel and fisetin) into nanoliposomes and nanoemulsions are described, as well as their relevance in current clinical trials. Then, polymeric nanoparticles are presented, namely the ones comprising poly lactic-co-glycolic acid, polyethylene glycol (and PEG dilemma) and dendrimers. The relevance of quantum dots in bioimaging is also covered, namely the systems with zinc sulfide and indium phosphide. Afterwards, we have reviewed gold nanoparticles (spheres and anisotropic) and their application in plasmon-induced photothermal therapy. The clinical relevance of iron oxide nanoparticles, such as magnetite and maghemite, has been analyzed in different fields, namely for magnetic resonance imaging, immunotherapy, hyperthermia, and drug delivery. Lastly, we have covered the recent advances in the systems using carbon nanomaterials, namely graphene oxide, carbon nanotubes, fullerenes, and carbon dots. Finally, we have compared the strategies of passive and active targeting of nanoparticles and their relevance in cancer theranostics. This review aims to be a (nano)mark on the ongoing journey towards realizing the remarkable potential of different nanoparticles in the realm of cancer therapeutics.

The Thermophysical and Physicochemical Properties of the Aqueous Dispersion of Graphene Oxide Dual-Beam Thermal Lens Spectrometry

Modern heat-conducting materials require special attention to analyze their thermophysical properties. Compared to classical methods, thermal lens spectrometry (TLS) has advantages due to its high sensitivity to physical and chemical composition. To avoid a systematic error in the analysis of complex systems, it is necessary to realize the limits of the applicability of the method. This study considers the features of thermal-diffusivity measurements by TLS in the stationary state for dispersed systems with absorbances up to 0.05. The limits of applicability of the method in analyzing heterogeneous systems are shown, and a mathematical apparatus is proposed for indicating a systematic error in finding thermal diffusivity that does not exceed 1%. Graphene oxide (GO), which has attractive physicochemical properties, was used as the object of analysis. GO belongs to 2D objects, the study of which requires highly sensitive methods and special attention when discussing the results. The thermophysical properties of aqueous dispersions of graphene oxide in a wide range of concentrations (up to 2 g/L) and lateral sizes (up to 4 µm) were studied by TLS. It has been found that with increasing nanophase concentration, the thermal diffusivity of graphene oxide dispersions passes through a minimum, which can be used in solving thermal insulation problems. It has been established that prolonged laser irradiation of the dispersion leads to a change in thermal diffusivity, which indicates the photochemical reduction of graphene oxide.

Multiple Bioimaging Applications Based on the Excellent Properties of Nanodiamond: A Review

Nanodiamonds (NDs) are emerging as a promising candidate for multimodal bioimaging on account of their optical and spectroscopic properties. NDs are extensively utilized for bioimaging probes due to their defects and admixtures in their crystal lattice. There are many optically active defects presented in NDs called color centers, which are highly photostable, extremely sensitive to bioimaging, and capable of electron leap in the forbidden band; further, they absorb or emit light when leaping, enabling the nanodiamond to fluoresce. Fluorescent imaging plays a significant role in bioscience research, but traditional fluorescent dyes have some drawbacks in physical, optical and toxicity aspects. As a novel fluorescent labeling tool, NDs have become the focus of research in the field of biomarkers in recent years because of their various irreplaceable advantages. This review primarily focuses on the recent application progress of nanodiamonds in the field of bioimaging. In this paper, we will summarize the progress of ND research from the following aspects (including fluorescence imaging, Raman imaging, X-ray imaging, magnetic modulation fluorescence imaging, magnetic resonance imaging, cathodoluminescence imaging, and optical coherence tomography imaging) and expect to supply an outlook contribution for future nanodiamond exploration in bioimaging.

Carbon Nanomaterials: Emerging Roles in Immuno-Oncology

Cancer immunotherapy has made breakthrough progress in cancer treatment. However, only a subset of patients benefits from immunotherapy. Given their unique structure, composition, and interactions with the immune system, carbon nanomaterials have recently attracted tremendous interest in their roles as modulators of antitumor immunity. Here, we focused on the latest advances in the immunological effects of carbon nanomaterials. We also reviewed the current preclinical applications of these materials in cancer therapy. Finally, we discussed the challenges to be overcome before the full potential of carbon nanomaterials can be utilized in cancer therapies to ultimately improve patient outcomes.

An Updated Review on Advances in Hydrogel-Based Nanoparticles for Liver Cancer Treatment

More than 90% of all liver malignancies are hepatocellular carcinomas (HCCs), for which chemotherapy and immunotherapy are the ideal therapeutic choices. Hepatocellular carcinoma is descended from other liver diseases, such as viral hepatitis, alcoholism, and metabolic syndrome. Normal cells and tissues may suffer damage from common forms of chemotherapy. In contrast to systemic chemotherapy, localized chemotherapy can reduce side effects by delivering a steady stream of chemotherapeutic drugs directly to the tumor site. This highlights the significance of controlled-release biodegradable hydrogels as drug delivery methods for chemotherapeutics. This review discusses using hydrogels as drug delivery systems for HCC and covers thermosensitive, pH-sensitive, photosensitive, dual-sensitive, and glutathione-responsive hydrogels. Compared to conventional systemic chemotherapy, hydrogel-based drug delivery methods are more effective in treating cancer.

Functionalized Carbon Nanoparticles as Theranostic Agents and Their Future Clinical Utility in Oncology

Over the years, research of nanoparticle applications in pre-clinical and clinical applications has greatly advanced our therapeutic and imaging approaches to many diseases, most notably neoplastic disorders. In particular, the innate properties of inorganic nanomaterials, such as gold and iron oxide, as well as carbon-based nanoparticles, have provided the greatest opportunities in cancer theranostics. Carbon nanoparticles can be used as carriers of biological agents to enhance the therapeutic index at a tumor site. Alternatively, they can also be combined with external stimuli, such as light, to induce irreversible physical damaging effects on cells. In this review, the recent advances in carbon nanoparticles and their use in cancer theranostics will be discussed. In addition, the set of evaluations that will be required during their transition from laboratory investigations toward clinical trials will be addressed.

Antimicrobial Activity of Graphene-Based Nanocomposites: Synthesis, Characterization, and Their Applications for Human Welfare

Graphene (GN)-related nanomaterials such as graphene oxide, reduced graphene oxide, quantum dots, etc., and their composites have attracted significant interest owing to their efficient antimicrobial properties and thus newer GN-based composites are being readily developed, characterized, and explored for clinical applications by scientists worldwide. The GN offers excellent surface properties, i.e., a large surface area, pH sensitivity, and significant biocompatibility with the biological system. In recent years, GN has found applications in tissue engineering owing to its impressive stiffness, mechanical strength, electrical conductivity, and the ability to innovate in two-dimensional (2D) and three-dimensional (3D) design. It also offers a photothermic effect that potentiates the targeted killing of cells via physicochemical interactions. It is generally synthesized by physical and chemical methods and is characterized by modern and sophisticated analytical techniques such as NMR, Raman spectroscopy, electron microscopy, etc. A lot of reports show the successful conjugation of GN with existing repurposed drugs, which improves their therapeutic efficacy against many microbial infections and also its potential application in drug delivery. Thus, in this review, the antimicrobial potentialities of GN-based nanomaterials, their synthesis, and their toxicities in biological systems are discussed.

Nitrogen-Doped Carbon Nanotube Cups for Cancer Therapy

Carbon nanomaterials have attracted significant attention for a variety of biomedical applications including sensing and detection, photothermal therapy, and delivery of therapeutic cargo. The ease of chemical functionalization, tunable length scales and morphologies, and ability to undergo complete enzymatic degradation make carbon nanomaterials an ideal drug delivery system. Much work has been done to synthesize carbon nanomaterials ranging from carbon dots, graphene, and carbon nanotubes to carbon nanocapsules, specifically carbon nanohorns or nitrogen-doped carbon nanocups. Here, we analyze specific properties of nitrogen-doped carbon nanotube cups which have been designed and utilized as drug delivery systems with the focus on the loading of these nanocapsules with specific therapeutic cargo and the targeted delivery for cancer therapy. We also summarize our targeted synthesis of gold nanoparticles on the open edge of nitrogen-doped carbon nanotube cups to create loaded and sealed nanocarriers for the delivery of chemotherapeutic agents to myeloid regulatory cells responsible for the immunosuppressive properties of the tumor microenvironment and thus tumor immune escape.

Applications of Pristine and Functionalized Carbon Nanotubes, Graphene, and Graphene Nanoribbons in Biomedicine

This review is dedicated to a comprehensive description of the latest achievements in the chemical functionalization routes and applications of carbon nanomaterials (CNMs), such as carbon nanotubes, graphene, and graphene nanoribbons. The review starts from the description of noncovalent and covalent exohedral modification approaches, as well as an endohedral functionalization method. After that, the methods to improve the functionalities of CNMs are highlighted. These methods include the functionalization for improving the hydrophilicity, biocompatibility, blood circulation time and tumor accumulation, and the cellular uptake and selectivity. The main part of this review includes the description of the applications of functionalized CNMs in bioimaging, drug delivery, and biosensors. Then, the toxicity studies of CNMs are highlighted. Finally, the further directions of the development of the field are presented.

Graphene-based hybrid materials as promising scaffolds for peripheral nerve regeneration

Peripheral nerve injury (PNI) is a serious clinical health problem caused by the damage of peripheral nerves which results in neurological deficits and permanent disability. There are several factors that may cause PNI such as localized damage (car accident, trauma, electrical injury) and outbreak of the systemic diseases (autoimmune or diabetes). While various diagnostic procedures including X-ray, magnetic resonance imaging (MRI), as well as other type of examinations such as electromyography or nerve conduction studies have been efficiently developed, a full recovery in patients with PNI is in many cases deficient or incomplete. This is the reason why additional therapeutic strategies should be explored to favor a complete rehabilitation in order to get appropriate nerve injury regeneration. The use of biomaterials acting as scaffolds opens an interesting approach in regenerative medicine and tissue engineering applications due to their ability to guide the growth of new tissues, adhesion and proliferation of cells including the expression of bioactive signals. This review discusses the preparation and therapeutic strategies describing in vitro and in vivo experiments using graphene-based materials in the context of PNI and their ability to promote nerve tissue regeneration.

Carbon Nanomaterials for Electro-Active Structures: A Review

The use of electrically conductive materials to impart electrical properties to substrates for cell attachment proliferation and differentiation represents an important strategy in the field of tissue engineering. This paper discusses the concept of electro-active structures and their roles in tissue engineering, accelerating cell proliferation and differentiation, consequently leading to tissue regeneration. The most relevant carbon-based materials used to produce electro-active structures are presented, and their main advantages and limitations are discussed in detail. Particular emphasis is put on the electrically conductive property, material synthesis and their applications on tissue engineering. Different technologies, allowing the fabrication of two-dimensional and three-dimensional structures in a controlled way, are also presented. Finally, challenges for future research are highlighted. This review shows that electrical stimulation plays an important role in modulating the growth of different types of cells. As highlighted, carbon nanomaterials, especially graphene and carbon nanotubes, have great potential for fabricating electro-active structures due to their exceptional electrical and surface properties, opening new routes for more efficient tissue engineering approaches.

Effective Photodynamic Therapy for Colon Cancer Cells Using Chlorin e6 Coated Hyaluronic Acid-Based Carbon Nanotubes

Colon cancer is the third major cancer contributor to mortality worldwide. Nanosized particles have attracted attention due to their possible contribution towards cancer treatment and diagnosis. Photodynamic therapy (PDT) is a cancer therapeutic modality that involves a light source, a photosensitizer and reactive oxygen species. Carbon nanotubes are fascinating nanocarriers for drug delivery, cancer diagnosis and numerous potential applications due to their unique physicochemical properties. In this study, single walled carbon nanotubes (SWCNTs) were coupled with hyaluronic acid (HA) and chlorin e6 (Ce6) coated on the walls of SWCNTs. The newly synthesized nanobiocomposite was characterized using ultraviolet-visible spectroscopy, Fourier transform electron microscopy (FTIR), X-ray diffraction analysis (XRD), particle size analysis and zeta potential. The loading efficiency of the SWCNTs-HA for Ce6 was calculated. The toxicity of the nanobiocomposite was tested on colon cancer cells using PDT at a fluence of 5 J/cm² and 10 J/cm². After 24 h, cellular changes were observed via microscopy, LDH cytotoxicity assay and cell death induction using annexin propidium iodide. The results showed that the newly synthesized nanobiocomposite enhanced the ability of PDT to be a photosensitizer carrier and induced cell death in colon cancer cells.

Carbonaceous Nanomaterials Employed in the Development of Electrochemical Sensors Based on Screen-Printing Technique—A Review

This paper aims to revise research on carbonaceous nanomaterials used in developing sensors. In general, nanomaterials are known to be useful in developing high-performance sensors due to their unique physical and chemical properties. Thus, descriptions were made for various structural features, properties, and manner of functionalization of carbon-based nanomaterials used in electrochemical sensors. Of the commonly used technologies in manufacturing electrochemical sensors, the screen-printing technique was described, highlighting the advantages of this type of device. In addition, an analysis was performed in point of the various applications of carbon-based nanomaterial sensors to detect analytes of interest in different sample types.

Electrically-Conductive Polyketone Nanocomposites Based on Reduced Graphene Oxide

In this work, we investigated the functionalization of polyketone 30 (PK30) with glycyl-glycine (Gly-Gly) via the Paal-Knorr reaction with the aim of homogenously dispersing two types of reduced graphene oxide (rGO, i.e., lrGO and hrGO, the former characterized by a lower degree of reduction in comparison to the latter) by non-covalent interactions. The functional PK30-Gly-Gly polymer was effective in preparing composites with homogeneously distributed rGO characterized by an effective percolation threshold at 5 wt. %. All the composites showed a typical semiconductive behavior and stable electrical response after several heating/cooling cycles from 30 to 115 °C. Composites made by hrGO displayed the same resistive behaviour even if flanked by a considerable improvement on conductivity, in agreement with the more reduced rGO content. Interestingly, no permanent percolative network was shown by the composite with 4 wt. % of lrGO at temperatures higher than 45 °C. This material can be used as an ON-OFF temperature sensor and could find interesting applications as sensing material in soft robotics applications.