Functionalization of Reduced Graphene Oxide via Thiol-Maleimide "Click" Chemistry: Facile Fabrication of Targeted Drug Delivery Vehicles

The preparation and characterization of graphene oxide-multiwalled minocycline coatings on ultrafine-grained titanium implants for enhanced performance studies

As the dental implant restoration technology is constantly applied and developed, implant fracture and related infections have emerged as significant factors threatening the long-term outcome of implants. Hence, this experiment intends to bestow the implant itself with anti-fracture and antibacterial capabilities by utilizing ultrafine-grained titanium, which possesses relatively superior mechanical properties, as the implant material and depositing a graphene oxide-minocycline composite coating on its surface. This is done to prevent implant fracture and the initial attachment of early microorganisms, and to strive to impede the colonization of late microorganisms and the formation of infectious biofilms, thereby achieving long-term stability of the implant. The graphene oxide-minocycline composite coating can be successfully fabricated on the surface of ultrafine-grained titanium via electrochemical deposition and liquid-phase deposition techniques, which can enhance the hydrophilicity of ultrafine-grained titanium and exhibit good coating adhesion. It demonstrates excellent antibacterial properties against Staphylococcus aureus, has no in vitro hemolysis, and shows no obvious cytotoxicity to mouse pre-osteoblasts.

Diverse reactivity of maleimides in polymer science and beyond

Maleimides are remarkably versatile functional groups, capable of participating in homo- and copolymerizations, Diels-Alder and (photo)cycloadditions, Michael additions, and other reactions. Their reactivity has afforded materials ranging from polyimides with high upper service temperatures to hydrogels for regenerative medicine applications. Moreover, maleimides have proven to be an enabling chemistry for pharmaceutical development and bioconjugation via straightforward modification of cysteine residues. To exert spatiotemporal control over reactions with maleimides, multiple approaches have been developed to photocage nucleophiles, dienes, and dipoles. Additionally, further substitution of the maleimide alkene (e.g., mono- and di-halo-, thio-, amino-, and methyl-maleimides, among other substituents) confers tunable reactivity and dynamicity, as well as responsive mechanical and optical properties. In this mini-review, we highlight the diverse functionality of maleimides, underscoring their notable impact in polymer science. This moiety and related heterocycles will play an important role in future innovations in chemistry, biomedical, and materials research.

Folate receptor-targeted thiol-maleimide clicked chitosan/carboxymethyl cellulose nanoparticles for cisplatin delivery in oral carcinoma

This study aimed to develop cisplatin (CDDP)-loaded folic acid (FA)-decorated nanoparticles (NPs) as targeted drug carrier towards overexpressed folate receptors on the oral carcinoma cell line (KB cells). The FA-conjugated thiolated succinyl chitosan (FA-SH-SCS) and maleimide-grafted-carboxymethyl cellulose (CMC-MAL) were synthesized and acquired in the preparation of NPs via thiol-maleimide click reaction. The physicochemical characteristics, drug loading, and drug release of the FA-decorated NPs (FA-NPs) were examined. Also, the in vitro biocompatibility, cellular uptake, and cell death mechanism were investigated. Relatively spherical NPs with negative charge were obtained with a size of approximately 200 nm. The formation of FA-NPs through click reaction was confirmed by the pH change and Ellman's assay. The release of CDDP from the FA-NPs was influenced by the acidic tumor environment. The FA-NPs were non-toxic to the normal cells. Furthermore, FA-NPs improved the cellular uptake of CDDP in oral carcinoma cells through specific recognition of folate receptors by FA-NPs. The delivery of CDDP by FA-NPs to the KB cell induced the apoptotic cell death pathway. Therefore, FA-NPs presented the potential to be effective nanocarriers for CDDP delivery in the treatment of oral cancer via active targeting approach.

Combined Graphene Oxide with 2-Methoxyestradiol for Effective Anticancer Therapy in-vitro Model

Introduction

This article describes the invention of graphene oxide (GO) or reduced graphene oxide (rGO) functionalised with 2-methoxy estradiol. The presence of polar hydroxyl groups enables the binding of 2-ME to GO/rGO through hydrogen bonds with epoxy and hydroxyl groups located on the surface and carbonyl and carboxyl groups located at the edges of graphene flake sheets.

Methods

The patented method of producing the subject of the invention and the research results regarding its anticancer effectiveness via cytotoxicity in an in vivo model (against A375 melanoma and 143B osteosarcoma cells) are described.

Results

It was shown that the inhibition of PTP1B phosphotyrosine phosphatase is one of the mechanisms of action of GO functionalised with 2-ME (GO-2-ME). This is a very important result, considering the fact that 2-ME itself has no inhibitory properties against this phosphatase.

Discussion

Graphene oxide flakes embroidered with 2-methoxyestradiol molecules may be a promising solution, bringing a new and important effect in the form of improving the bioavailability of the therapeutic substance, ie 2-ME. An appropriate dosage of GO-2-ME/rGO-2-ME, in which GO/rGO is a carrier of 2-methoxyestradiol (2-ME), can ensure effective penetration of the active substance through biological boundaries/membranes and controlled modification of cell signalling, ultimately leading to the selective elimination of malignant cells.

Magnetic Microrobots for In Vivo Cargo Delivery: A Review

Magnetic microrobots, with their small size and agile maneuverability, are well-suited for navigating the intricate and confined spaces within the human body. In vivo cargo delivery within the context of microrobotics involves the use of microrobots to transport and administer drugs and cells directly to the targeted regions within a living organism. The principal aim is to enhance the precision, efficiency, and safety of therapeutic interventions. Despite their potential, there is a shortage of comprehensive reviews on the use of magnetic microrobots for in vivo cargo delivery from both research and engineering perspectives, particularly those published after 2019. This review addresses this gap by disentangling recent advancements in magnetic microrobots for in vivo cargo delivery. It summarizes their actuation platforms, structural designs, cargo loading and release methods, tracking methods, navigation algorithms, and degradation and retrieval methods. Finally, it highlights potential research directions. This review aims to provide a comprehensive summary of the current landscape of magnetic microrobot technologies for in vivo cargo delivery. It highlights their present implementation methods, capabilities, and prospective research directions. The review also examines significant innovations and inherent challenges in biomedical applications.

Chasing Graphene-Based Anticancer Drugs: Where are We Now on the Biomedical Graphene Roadmap?

Graphene and graphene-based materials have attracted growing interest for potential applications in medicine because of their good biocompatibility, cargo capability and possible surface functionalizations. In parallel, prototypic graphene-based devices have been developed to diagnose, imaging and track tumor growth in cancer patients. There is a growing number of reports on the use of graphene and its functionalized derivatives in the design of innovative drugs delivery systems, photothermal and photodynamic cancer therapy, and as a platform to combine multiple therapies. The aim of this review is to introduce the latest scientific achievements in the field of innovative composite graphene materials as potentially applied in cancer therapy. The "Technology and Innovation Roadmap" published in the Graphene Flagship indicates, that the first anti-cancer drugs using graphene and graphene-derived materials will have appeared on the market by 2030. However, it is necessary to broaden understanding of graphene-based material interactions with cellular metabolism and signaling at the functional level, as well as toxicity. The main aspects of further research should elucidate how treatment methods (e.g., photothermal therapy, photodynamic therapy, combination therapy) and the physicochemical properties of graphene materials influence their ability to modulate autophagy and kill cancer cells. Interestingly, recent scientific reports also prove that graphene nanocomposites modulate cancer cell death by inducing precise autophagy dysfunctions caused by lysosome damage. It turns out as well that developing photothermal oncological treatments, it should be taken into account that near-infrared-II radiation (1000-1500 nm) is a better option than NIR-I (750-1000 nm) because it can penetrate deeper into tissues due to less scattering at longer wavelengths radiation.

Immobilizing c(RGDfc) on the surface of metal-phenolic networks by thiol-click reaction for accelerating osteointegration of implant

The limited osteointegration often leads to the failure of implant, which can be improved by fixing bioactive molecules onto the surface, such as arginyl-glycyl-aspartic acid (RGD): a cell adhesion motif. Metal-Phenolic Networks (MPNs) have garnered increasing attention from different disciplines in recent years due to their simple and rapid process for depositing on various substrates or particles with different shapes. However, the lack of cellular binding sites on MPNs greatly blocks its application in tissue engineering. In this study, we present a facile and efficient approach for producing PC/Fe@c(RGDfc) composite coatings through the conjugation of c(RGDfc) peptides onto the surface of PC/Fe-MPNs utilizing thiol-click reaction. By combined various techniques (ellipsometry, X-ray photoelectron spectroscopy, Liquid Chromatography-Mass Spectrometry, water contact angle, scanning electronic microscopy, atomic force microscopy) the physicochemical properties (composition, coating mechanism and process, modulus and hydrophilicity) of PC/Fe@c(RGDfc) surface were characterized in detail. In addition, the PC/Fe@c(RGDfc) coating exhibits the remarkable ability to positively modulate cellular attachment, proliferation, migration and promoted bone-implant integration in vivo, maintaining the inherent features of MPNs: anti-inflammatory, anti-oxidative properties, as well as multiple substrate deposition. This work contributes to engineering MPNs-based coatings with bioactive molecules by a facile and efficient thiol-click reaction, as an innovative perspective for future development of surface modification of implant materials.

Two-dimensional nanomaterials induced nano-bio interfacial effects and biomedical applications in cancer treatment

Two-dimensional nanomaterials (2D NMs), characterized by a large number of atoms or molecules arranged in one dimension (typically thickness) while having tiny dimensions in the other two dimensions, have emerged as a pivotal class of materials with unique properties. Their flat and sheet-like structure imparts distinctive physical, chemical, and electronic attributes, which offers several advantages in biomedical applications, including enhanced surface area for efficient drug loading, surface-exposed atoms allowing precise chemical modifications, and the ability to form hierarchical multilayer structures for synergistic functionality. Exploring their nano-bio interfacial interactions with biological components holds significant importance in comprehensively and systematically guiding safe applications. However, the current lack of in-depth analysis and comprehensive understanding of interfacial effects on cancer treatment motivates our ongoing efforts in this field. This study provides a comprehensive survey of recent advances in utilizing 2D NMs for cancer treatment. It offers insights into the structural characteristics, synthesis methods, and surface modifications of diverse 2D NMs. The investigation further delves into the formation of nano-bio interfaces during their in vivo utilization. Notably, the study discusses a wide array of biomedical applications in cancer treatment. With their potential to revolutionize therapeutic strategies and outcomes, 2D NMs are poised at the forefront of cancer treatment, holding the promise of transformative advancements.

Graphene Oxide (GO) for the Treatment of Bone Cancer: A Systematic Review and Bibliometric Analysis

Cancer is a severe disease that, in 2022, caused more than 9.89 million deaths worldwide. One worrisome type of cancer is bone cancer, such as osteosarcoma and Ewing tumors, which occur more frequently in infants. This study shows an active interest in the use of graphene oxide and its derivatives in therapy against bone cancer. We present a systematic review analyzing the current state of the art related to the use of GO in treating osteosarcoma, through evaluating the existing literature. In this sense, studies focused on GO-based nanomaterials for potential applications against osteosarcoma were reviewed, which has revealed that there is an excellent trend toward the use of GO-based nanomaterials, based on their thermal and anti-cancer activities, for the treatment of osteosarcoma through various therapeutic approaches. However, more research is needed to develop highly efficient localized therapies. It is suggested, therefore, that photodynamic therapy, photothermal therapy, and the use of nanocarriers should be considered as non-invasive, more specific, and efficient alternatives in the treatment of osteosarcoma. These options present promising approaches to enhance the effectiveness of therapy while also seeking to reduce side effects and minimize the damage to surrounding healthy tissues. The bibliometric analysis of photothermal and photochemical treatments of graphene oxide and reduced graphene oxide from January 2004 to December 2022 extracted 948 documents with its search strategy, mainly related to research papers, review papers, and conference papers, demonstrating a high-impact field supported by the need for more selective and efficient bone cancer therapies. The central countries leading the research are the United States, Iran, Italy, Germany, China, South Korea, and Australia, with strong collaborations worldwide. At the same time, the most-cited papers were published in journals with impact factors of more than 6.0 (2021), with more than 290 citations. Additionally, the journals that published the most on the topic are high impact factor journals, according to the analysis performed, demonstrating the high impact of the research field.

Application of graphene oxide in tumor targeting and tumor therapy

Graphene oxide (GO), as a kind of two-dimensional sp2 carbon nanomaterials, has attracted great attention in many fields in the past decade. Due to its unique physical and chemical properties, GO is showing great promise in the field of biomedicine. For GO, all the atoms on its surface are exposed to the surface with ultra-high specific surface area, and a variety of groups on the surface, such as carboxyl, hydroxyl and epoxy groups, can effectively bind/load various biomolecules. Due to the availability of these groups, GO also possesses excellent hydrophilicity and biocompatibility for the modification of the desired biocompatible molecules or polymers on the surface of GO. The nano-network structure and hydrophobicity of GO enable it to load a large number of hydrophobic drugs containing benzene rings and it has been widely used as a multi-functional nano-carrier for chemotherapeutic drug or gene delivery. This review article will give an in-depth overview of the synthesis methods of GO, the advantages and disadvantages of GO used in nano-drug delivery system, the research progress of GO as a stimulus-responsive nano-drug carrier, and the application of these intelligent systems in cancer treatment.

The "How" and "Where" Behind the Functionalization of Graphene Oxide by Thiol-ene "Click" Chemistry

Graphene oxide (GO) is a 2D nanomaterial with unique chemistry due to the combination of sp2 hybridization and oxygen functional groups (OFGs) even in single layer. OFGs play a fundamental role in the chemical functionalization of GO to produce GO-based materials for diverse applications. However, traditional strategies that employ epoxides, alcohols, and carboxylic acids suffer from low control and undesirable side reactions, including by-product formation and GO reduction. Thiol-ene "click" reaction offers a promising and versatile chemical approach for the alkene functionalization (-C=C-) of GO, providing orthogonality, stereoselectivity, regioselectivity, and high yields while reducing by-products. This review examines the chemical functionalization of GO via thiol-ene "click" reactions, providing insights into the underlying reaction mechanisms, including the role of radical or base catalysts in triggering the reaction. We discuss the "how" and "where" the reaction takes place on GO, the strategies to avoid unwanted side reactions, such as GO reduction and by-product formation. We anticipate that multi-functionalization of GO via the alkene groups will enhance GO physicochemical properties while preserving its intrinsic chemistry.

Applications of graphene-based nanomaterials in drug design: The good, the bad and the ugly

INTRODUCTION

Graphene-based materials (GBMs) have unique physicochemical properties that make them extremely attractive as platforms for the design of new drugs. Indeed, their bidimensional (2D) morphology, high surface area, mechanical and optical properties, associated to different possibilities for functionalization of their surface, provides opportunities for their use as nanomedicines for drug delivery and/or phototherapies.

AREAS COVERED

This opinion paper provides an overview of the current status of GBMs in drug design, with a focus on their therapeutic applications, potential environmental and health risks, and some controversial results. The authors discuss the chemical modifications of GBMs for the treatment of various diseases. The potential toxicity associated with some GBMs is also presented, along with a safe-by-design approach to minimize the risks. Finally, the authors address some issues associated to the use of GBMs in the biomedical field, such as contradictory antibacterial effects, fluorescence quenching and imprecise chemical functionalization.

EXPERT OPINION

GBMs are a promising and exciting area of research in drug delivery. It is however important that responsible and safe use of these materials is ensured to fully exploit their advantages and overcome their drawbacks.

Repetitive self-healing of Diels-Alder grafted graphene nanoplatelet reinforced carbon fiber reinforced polymer composites with outstanding mechanical properties

The concept of using bio-inspired healing mechanisms in fiber-reinforced polymer (FRP)-based laminated composites is one of the trending areas of research for lightweight high-performance materials. To introduce self-healing in laminated composites, we developed Diels-Alder (DA) grafted graphene nanoplatelets (GNPs) and introduced them into carbon-fiber-reinforced polymer (CFRP) composites. The DA-grafted GNPs provided dual benefits, such as repetitive self-healing along with an increased mechanical performance of the modified CFRP. The GNPs were functionalized with DA adducts, i.e., bismaleimide and furfurylamine via a facile functionalization approach. The highest healing efficiency evaluated using double cantilever beam (DCB) tests was observed as ∼87% with more than 10 times repeated healing cycles. The innovative concept and strategy proposed in this work could be a gateway to a new area of research to upscale for industrialization of DA-based repetitive self-healable and durable CFRP-based composites.

Cell-binding peptides on the material surface guide stem cell fate of adhesion, proliferation and differentiation

Human cells, especially stem cells, need to communicate and interact with extracellular matrix (ECM) proteins, which not only serve as structural components but also guide and support cell fate and properties such as cell adhesion, proliferation, survival and differentiation. The binding of the cells with ECM proteins or ECM-derived peptides via cell adhesion receptors such as integrins activates several signaling pathways that determine the cell fate, morphological change, proliferation and differentiation. The development of synthetic ECM protein-derived peptides that mimic the biological and biochemical functions of natural ECM proteins will benefit academic and clinical application. Peptides derived from or inspired by specific ECM proteins can act as agonists of each ECM protein receptor. Given that most ECM proteins function in cell adhesion via integrin receptors, many peptides have been developed that bind to specific integrin receptors. In this review, we discuss the peptide sequence, immobilization design, reaction method, and functions of several ECM protein-derived peptides. Various peptide sequences derived from mainly ECM proteins, which are used for coating or grafting on dishes, scaffolds, hydrogels, implants or nanofibers, have been developed to improve the adhesion, proliferation or differentiation of stem cells and to culture differentiated cells. This review article will help to inform the optimal choice of ECM protein-derived peptides for the development of scaffolds, implants, hydrogels, nanofibers and 2D cell culture dishes to regulate the proliferation and direct the differentiation of stem cells into specific lineages.

CuAAC ensembled 1,2,3-triazole linked nanogels for targeted drug delivery: a review

Copper(i) catalyzed alkyne azide cycloaddition (CuAAC), the quintessential example of 'click chemistry', provides an adaptable and adequate platform for the synthesis of nanogels for sustained drug release at targeted sites because of their better biocompatibility. The coupling of drugs, carried out via various synthetic routes including CuAAC, into long-chain polymeric forms like nanogels has exhibited considerable assurance in therapeutic advancements and intracellular drug delivery due to the progression of water solubility, evacuation of precocious drug release, and improved upthrust of the pharmacokinetics of the nanogels, thereby rendering them as better and efficient drug carriers. The inefficiency of drug transmission to the target areas due to the resistance of complex biological barriers in vivo is a major hurdle that impedes the therapeutic translation of nanogels. This review compiles the data of nanogels synthesized specifically via CuAAC 'click' methodology, as scaffolds for targeted drug delivery and their assimilation into nanomedicine. In addition, it elaborates the ability of CuAAC to graft specific moieties and conjugating biomolecules like proteins and growth factors, onto orthogonally functionalized polymer chains with various chemical groups resulting in nanogels that are not only more appealing but also more effective at delivering drugs, thereby enhancing their site-specific target approach and initiating selective therapies.

Biological Impacts of Reduced Graphene Oxide Affected by Protein Corona Formation

Applications of reduced graphene oxide (rGO) in many different areas have been gradually increasing owing to its unique physicochemical characteristics, demanding more understanding of their biological impacts. Herein, we assessed the toxicological effects of rGO in mammary epithelial cells. Because the as-synthesized rGO was dissolved in sodium cholate to maintain a stable aqueous dispersion, we hypothesize that changing the cholate concentration in the dispersion may alter the surface property of rGO and subsequently affect its cellular toxicity. Thus, four types of rGO were prepared and compared: rGO dispersed in 4 and 2 mg/mL sodium cholate, labeled as rGO and concentrated-rGO (c-rGO), respectively, and rGO and c-rGO coated with a protein corona through 1 h incubation in culture media, correspondingly named pro-rGO and pro-c-rGO. Notably, c-rGO and pro-c-rGO exhibited higher toxicity than rGO and pro-rGO and also caused higher reactive oxygen species production, more lipid membrane peroxidation, and more significant disruption of mitochondrial-based ATP synthesis. In all toxicological assessments, pro-c-rGO induced more severe adverse impacts than c-rGO. Further examination of the material surface, protein adsorption, and cellular uptake showed that the surface of c-rGO was coated with a lower content of surfactant and adsorbed more proteins, which may result in the higher cellular uptake observed with pro-c-rGO than pro-rGO. Several proteins involved in cellular redox mediation were also more enriched in pro-c-rGO. These results support the strong correlation between dispersant coating and corona formation and their subsequent cellular impacts. Future studies in this direction could reveal a deeper understanding of the correlation and the specific cellular pathways involved and help gain knowledge on how the toxicity of rGO could be modulated through surface modification, guiding the sustainable applications of rGO.

Carbon Graphitization: Towards Greener Alternatives to Develop Nanomaterials for Targeted Drug Delivery

Carbon nanomaterials have attracted great interest for their unique physico-chemical properties for various applications, including medicine and, in particular, drug delivery, to solve the most challenging unmet clinical needs. Graphitization is a process that has become very popular for their production or modification. However, traditional conditions are energy-demanding; thus, recent efforts have been devoted to the development of greener routes that require lower temperatures or that use waste or byproducts as a carbon source in order to be more sustainable. In this concise review, we analyze the progress made in the last five years in this area, as well as in their development as drug delivery agents, focusing on active targeting, and conclude with a perspective on the future of the field.

Innovative transdermal delivery of insulin using gelatin methacrylate-based microneedle patches in mice and mini-pigs

Painless and controlled on-demand drug delivery is the ultimate goal for the management of various chronic diseases, including diabetes. To achieve this purpose, microneedle patches are gaining increased attention. While degradable microneedle (MN) arrays are widely employed, the use of non-dissolving MN patches remains a challenge to overcome. In this study, we demonstrate that crosslinking gelatin methacrylate with polyethylene glycol diacrylate (PEGDA) is potent for engineering non-dissolving MN arrays. Incorporation of MoS2 nanosheets as a photothermal component into MN hydrogels results in MNs featuring on-demand release properties. An optimized MoS2-MN array patch formed using a hydrogel solution containing 500 μg mL-1 of MoS2 and photochemically crosslinked for 5 min shows required mechanical behavior under a normal compressive load to penetrate the stratum corneum of mice or pig skin and allows the delivery of macromolecular therapeutics such as insulin upon swelling. Using ex vivo and in vivo models, we show that the MoS2-MN patches can be used for loading and releasing insulin for therapeutic purposes. Indeed, transdermal administration of insulin loaded into MoS2-MN patches reduces blood glucose levels in C57BL/6 mice and mini-pigs comparably to subcutaneously injected insulin. We believe that this on-demand delivery system might alter the current insulin therapies and might be a potential approach for delivery of other proteins.

Synergistic Combination of Facile Thiol-Maleimide Derivatization and Supramolecular Solvent-Based Microextraction for UHPLC-HRMS Analysis of Glutathione in Biofluids

Glutathione (GSH) is the most abundant non-protein thiol in biofluids, enabling diverse physiological functions. Among the proposed methods for GSH detection, ultra-high-performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry (HRMS) has the advantages of high sensitivity and efficiency. In this study, a novel analytical method was developed for the determination of GSH using supramolecular solvent (SUPRAS)-based dispersive liquid–liquid microextraction (DLLME) and UHPLC–HRMS. N-Laurylmaleimide was dissolved in tetrahydrofuran, which served three functions: 1) precipitate the proteins present in the biofluid sample, 2) provide a reaction environment for derivatization, and 3) enable the use of SUPRAS as the dispersing agent. Critical parameters were optimized based on single factor testing and response surface methodology. The established method was validated in terms of linearity, accuracy, precision, and successful quantitative analysis of GSH in saliva, urine, and plasma samples. Experimental results showed that SUPRAS as an extraction solvent was particularly suitable for the extraction of GSH from complex matrices. The current study provides a useful tool for accurate measurements of GSH concentrations, which could potentially be used for clinical diagnostics.

Graphene and its derivatives: understanding the main chemical and medicinal chemistry roles for biomedical applications

Over the past few years, there has been a growing potential use of graphene and its derivatives in several biomedical areas, such as drug delivery systems, biosensors, and imaging systems, especially for having excellent optical, electronic, thermal, and mechanical properties. Therefore, nanomaterials in the graphene family have shown promising results in several areas of science. The different physicochemical properties of graphene and its derivatives guide its biocompatibility and toxicity. Hence, further studies to explain the interactions of these nanomaterials with biological systems are fundamental. This review has shown the applicability of the graphene family in several biomedical modalities, with particular attention for cancer therapy and diagnosis, as a potent theranostic. This ability is derivative from the considerable number of forms that the graphene family can assume. The graphene-based materials biodistribution profile, clearance, toxicity, and cytotoxicity, interacting with biological systems, are discussed here, focusing on its synthesis methodology, physicochemical properties, and production quality. Despite the growing increase in the bioavailability and toxicity studies of graphene and its derivatives, there is still much to be unveiled to develop safe and effective formulations.

Graphic abstract

Functionalized Graphene Platforms for Anticancer Drug Delivery

Two-dimensional nanomaterials are emerging as promising candidates for a wide range of biomedical applications including tissue engineering, biosensing, pathogen incapacitation, wound healing, and gene and drug delivery. Graphene, due to its high surface area, photothermal property, high loading capacity, and efficient cellular uptake, is at the forefront of these materials and plays a key role in this multidisciplinary research field. Poor water dispersibility and low functionality of graphene, however, hamper its hybridization into new nanostructures for future nanomedicine. Functionalization of graphene, either by covalent or non-covalent methods, is the most useful strategy to improve its dispersion in water and functionality as well as processability into new materials and devices. In this review, recent advances in functionalization of graphene derivatives by different (macro)molecules for future biomedical applications are reported and explained. In particular, hydrophilic functionalization of graphene and graphene oxide (GO) to improve their water dispersibility and physicochemical properties is discussed. We have focused on the anticancer drug delivery of polyfunctional graphene sheets.

Graphene-based nanomaterials for breast cancer treatment: promising therapeutic strategies

Breast cancer is the most common malignancy in women, and its incidence increases annually. Traditional therapies have several side effects, leading to the urgent need to explore new smart drug-delivery systems and find new therapeutic strategies. Graphene-based nanomaterials (GBNs) are potential drug carriers due to their target selectivity, easy functionalization, chemosensitization and high drug-loading capacity. Previous studies have revealed that GBNs play an important role in fighting breast cancer. Here, we have summarized the superior properties of GBNs and modifications to shape GBNs for improved function. Then, we focus on the applications of GBNs in breast cancer treatment, including drug delivery, gene therapy, phototherapy, and magnetothermal therapy (MTT), and as a platform to combine multiple therapies. Their advantages in enhancing therapeutic effects, reducing the toxicity of chemotherapeutic drugs, overcoming multidrug resistance (MDR) and inhibiting tumor metastasis are highlighted. This review aims to help evaluate GBNs as therapeutic strategies and provide additional novel ideas for their application in breast cancer therapy.

A Targeted Erythrocyte Membrane-Encapsulated Drug-Delivery System with Anti-osteosarcoma and Anti-osteolytic Effects

Chemotherapy is one of the main treatment methods for osteosarcoma. However, conventional chemotherapy lacks targeting properties, and its long-term and extensive use will have serious side effects on patients. For this reason, a multifunctional nanodrug system (V-RZCD) targeting osteosarcoma was developed in this study. V-RZCD consists of two parts: (1) the core (ZCD), wherein calcium ions (Ca2+) and zoledronic acid (ZA) form a metal-organic framework for loading doxorubicin (DOX), and (2) the shell (V-R), a vascular endothelial growth factor (VEGF) ligand-modified red blood cell membrane nanovesicle. By targeting the VEGF, V-RZCD can specifically bind to the VEGF receptors that are highly expressed on the surface of osteosarcoma cells. Importantly, compared with free ZA and DOX, V-RZCD not only clearly inhibits the proliferation of osteosarcoma but also significantly inhibits osteolysis induced by osteosarcoma. In summary, V-RZCD represents a new way to treat osteosarcoma.

Antimicrobial Polymeric Structures Assembled on Surfaces

Pathogenic microbes are the main cause of various undesired infections in living organisms, including humans. Most of these infections are favored in hospital environments where humans are being treated with antibiotics and where some microbes succeed in developing resistance to such drugs. As a consequence, our society is currently researching for alternative, yet more efficient antimicrobial solutions. Certain natural and synthetic polymers are versatile materials that have already proved themselves to be highly suitable for the development of the next-generation of antimicrobial systems that can efficiently prevent and kill microbes in various environments. Here, we discuss the latest developments of polymeric structures, exhibiting (reinforced) antimicrobial attributes that can be assembled on surfaces and coatings either from synthetic polymers displaying antiadhesive and/or antimicrobial properties or from blends and nanocomposites based on such polymers.

Drug Delivery With Carbon-Based Nanomaterials as Versatile Nanocarriers: Progress and Prospects

With growing interest, a large number of researches have been conducted on carbon-based nanomaterials (CBNs). However, their uses are limited due to comprehensive potential environmental and human health effects. It is often confusing for researchers to make an informed choice regarding the versatile carbon-based nanocarrier system and its potential applications. This review has highlighted emerging applications and cutting-edge progress of CBNs in drug delivery. Some critical factors like enzymatic degradation, surface modification, biological interactions, and bio-corona have been discussed here. These factors will help to fabricate CBNs for effective drug delivery. This review also addresses recent advancements in carbon-based target specific and release controlled drug delivery to improve disease treatment. The scientific community has turned their research efforts into the development of novel production methods of CBNs to make their production more attractive to the industrial sector. Due to the nanosize and diversified physical properties, these CBNs have demonstrated distinct biological interaction. Thus long-term preclinical toxicity study is recommended before finally translating to clinical application.

Functionalized Reduced Graphene Oxide as a Versatile Tool for Cancer Therapy

Cancer is one of the deadliest diseases in human history with extremely poor prognosis. Although many traditional therapeutic modalities-such as surgery, chemotherapy, and radiation therapy-have proved to be successful in inhibiting the growth of tumor cells, their side effects may vastly limited the actual benefits and patient acceptance. In this context, a nanomedicine approach for cancer therapy using functionalized nanomaterial has been gaining ground recently. Considering the ability to carry various anticancer drugs and to act as a photothermal agent, the use of carbon-based nanomaterials for cancer therapy has advanced rapidly. Within those nanomaterials, reduced graphene oxide (rGO), a graphene family 2D carbon nanomaterial, emerged as a good candidate for cancer photothermal therapy due to its excellent photothermal conversion in the near infrared range, large specific surface area for drug loading, as well as functional groups for functionalization with molecules such as photosensitizers, siRNA, ligands, etc. By unique design, multifunctional nanosystems could be designed based on rGO, which are endowed with promising temperature/pH-dependent drug/gene delivery abilities for multimodal cancer therapy. This could be further augmented by additional advantages offered by functionalized rGO, such as high biocompatibility, targeted delivery, and enhanced photothermal effects. Herewith, we first provide an overview of the most effective reducing agents for rGO synthesis via chemical reduction. This was followed by in-depth review of application of functionalized rGO in different cancer treatment modalities such as chemotherapy, photothermal therapy and/or photodynamic therapy, gene therapy, chemotherapy/phototherapy, and photothermal/immunotherapy.

Photothermally Active Cryogel Devices for Effective Release of Antimicrobial Peptides: On-Demand Treatment of Infections

There has been significant interest in the use of peptides as antimicrobial agents, and peptide containing hydrogels have been proposed as biological scaffolds for various applications. Limited stability and rapid clearance of small molecular weight peptides pose challenges to their widespread implementation. As a common approach, antibacterial peptides are physically loaded into hydrogel scaffolds, which leads to continuous release through the passive mode with spatial control but provides limited control over drug dosage. Although utilization of peptide covalent linkage onto hydrogels addresses partially this problem, the peptide release is commonly too slow. To alleviate these challenges, in this work, maleimide-modified antimicrobial peptides are covalently conjugated onto furan-based cryogel (CG) scaffolds via the Diels-Alder cycloaddition at room temperature. The furan group offers a handle for specific loading of the peptides, thus minimizing passive and burst drug release. The porous nature of the CG matrix provides rapid loading and release of therapeutic peptides, apart from high water uptake. Interfacing the peptide adduct containing a CG matrix with a reduced graphene oxide-modified Kapton substrate allows "on-demand" photothermal heating upon near-infrared (NIR) irradiation. A fabricated photothermal device enables tunable and efficient peptide release through NIR exposure to kill bacteria. Apart from spatial confinement offered by this CG-based bandage, the selective ablation of planktonic Staphylococcus aureus is demonstrated. It can be envisioned that this modular "on-demand" peptide-releasing device can be also employed for other topical applications by appropriate choice of therapeutic peptides.

Preparation and Insights of Smart Foams with Phototunable Foamability Based on Azobenzene-Containing Surfactants

Smart foams with tunable foamability exhibit superb applications in many fields such as colloidal and interface science. Herein, we have synthesized an azobenzene-containing surfactant with excellent photoresponsiveness by a simple thiol-maleimide click reaction between thioglycolic acid and 4-(N-maleimide) azobenzene (MAB). The structure and the photoresponsive behavior of the novel surfactant are characterized. Depending on the solution concentration, the synthesized surfactant demonstrated various speeds for the trans/cis photoisomerization varying from 9 to 24 s for the given concentration range and excellent reversible photoisomerization cycling stability (more than 20 cycles) upon light irradiation. Based on these conformational switches, a series of phototriggered obvious surface properties (e.g., critical micelle concentration (CMC), surface tension (γ), and surface excess concentration (Γ)) changes of the surfactant are achieved. More specifically, the smart foam system with tunable foamability is realized. As-formed smart foams with rapid photocontrolled reversible foaming/defoaming transition and excellent cycling stability make them very attractive candidates for applications in wastewater treatment, green textile, oil extraction, and emulsification.

Stabilizing sulfur vacancy defects by performing "click" chemistry of ultrafine palladium to trigger a high-efficiency hydrogen evolution of MoS2

Defect engineering is widely applied in transition metal dichalcogenides to produce high-purity hydrogen. However, the instability of vacancy states on catalysis still remains a considerable challenge. Here, our first-principles calculations showed that, by optimizing the asymmetric S vacancy in the highly asymmetric 1T' crystal of layered bitransition metal dichalcogenides (Co-MoS2) in light of Pd modulation, the relative amount of metastable phase and the quantity of active sites in the structure can be reduced and increased, respectively, leading to a further boosted hydrogen evolution reaction (HER) activity toward layered bi-transition metal dichalcogenides. Thus, we then used a "click" chemistry strategy to make such a catalyst with engineered unsaturated sulfur edges via a strong coupling effect between ultrafine Pd ensembles and Co-MoS2 nanosheets. As expected, the Pd-modulated Co-MoS2 nanosheets exhibited a very low overpotential of 60 mV at 10 mA cm-2 with a small Tafel slope (56 mV dec-1) for the HER in 1.0 M PBS, comparable to those of commercial Pt/C. In addition, their high HER activity was retained in acidic and alkaline conditions. Both the theoretical and experimental results revealed that Pd ensembles can efficiently activate and stabilize the inert basal plane S sites during HER processes as a result of the formation of Pd-S in Co-MoS2. This work not only provides a deeper understanding of the correlation between defect sites and intrinsic HER catalytic properties for transition metal chalcogenide (TMD)-based catalysts, but also offers new insights into better designing earth-abundant HER catalysts displaying high efficiency and durability.

Applications of Two-Dimensional Nanomaterials in Breast Cancer Theranostics

Breast cancer is the leading cause of cancer-related mortality among women. Early stage diagnosis and treatment of this cancer are crucial to patients' survival. In addition, it is important to avoid severe side effects during the process of conventional treatments (surgery, chemotherapy, hormonal therapy, and targeted therapy) and increase the patients' quality of life. Over the past decade, nanomaterials of all kinds have shown excellent prospects in different aspects of oncology. Among them, two-dimensional (2D) nanomaterials are unique due to their physical and chemical properties. The functional variability of 2D nanomaterials stems from their large specific surface area as well as the diversity of composition, electronic configurations, interlayer forces, surface functionalities, and charges. In this review, the current status of 2D nanomaterials in breast cancer diagnosis and therapy is reviewed. In this respect, sensing of the tumor biomarkers, imaging, therapy, and theranostics are discussed. The ever-growing 2D nanomaterials are building blocks for the development of a myriad of nanotheranostics. Accordingly, there is the possibility to explore yet novel properties, biological effects, and oncological applications.

Graphene oxide with in-situ grown Prussian Blue as an electrochemical probe for microRNA-122

An electrochemical biosensor for microRNA was constructed on the basis of direct growth of electroactive Prussian Blue (PB) on graphene oxide (GO). A mercapto-modified probe DNA that is complementary to the hepatocellular carcinoma biomarker microRNA-122 was firstly anchored on a gold electrode (AuE). Then, GO (with its large surface and multiple active sites) was adsorbed on probe DNA through π-interaction. Subsequently, the PB nanoparticles were directly grown on GO via alternative dipping the electrode in solutions of FeCl₃ and hexacyanoferrate(III). Upon incubation of the resulting electrode with a solution of microRNA-122, the probe DNA on the electrode interacts with microRNA-122 to form a rigid duplex. This results in the release of electroactive PB/GO from the sensing interface and a decrease in current, typically measured at 0.18 V (vs. Ag/AgCl (3 M KCl)). The sensor covers the 10 fM to 10 nM microRNA-122 concentration range and has a 1.5 fM detection limit. The method was successfully applied to the determination of microRNA-122 in real biological samples. Graphical abstract Graphene oxide with in-situ grown Prussian Blue is applied as an electrochemical probe for the analysis of microRNA-122.

Graphene-based advanced nanoplatforms and biocomposites from environmentally friendly and biomimetic approaches

Environmentally friendly and biomimetic approaches to fabricate graphene-based advanced nanoplatforms and biocomposites for biomedical applications are summarized in this review.

Magnetic glyconanoparticles for selective lectin separation and purification

A modular platform for the separation and purification of lectins using polymer coated iron oxide nanoparticles is developed.

Cu(0) nanoparticle-decorated functionalized reduced graphene oxide sheets as artificial peroxidase enzymes: application for colorimetric detection of Cr(vi) ions

Graphene oxide sheets were functionalized by a “click” chemistry approach which was utilized for the decoration of Cu(0) nanoparticles for sensitive colorimetric detection of Cr(vi) ions.

Design and Development of Graphene Oxide Nanoparticle/Chitosan Hybrids Showing pH-Sensitive Surface Charge-Reversible Ability for Efficient Intracellular Doxorubicin Delivery

A novel graphene oxide nanoparticle (GON)-based drug delivery system containing GONs as carriers of anticancer drugs and chitosan/dimethylmaleic anhydride-modified chitosan (CS/CS-DMMA) as surface charge-reversible shells is fabricated via the classic self-assembly of the deprotonated carboxyl of GONs and the protonated amine of the CS backbone by electrostatic interaction, and CS-DMMA serves as the outmost layer. In this GON-based drug delivery system, the GON cores as desired carriers might adsorb doxorubicin hydrochloride (DOX) via the π-π stacking interaction between the large π conjugated structures of GO and the aromatic structure of DOX. Meanwhile, the chitosan-based polyelectrolyte shells served as a smart protection screen to evade the premature release of the as-loaded DOX in normal extracellular condition, and then, the release of DOX was accelerated because of the detachment of chitosan coating at low pH. Furthermore, the re-exposure of amino groups after hydrolysis of CS-DMMA endowed the drug delivery system with positive surface charge by taking advantage of the pH difference between physiological conditions and the tumor microenvironment to enhance the cellular uptake. Then, the pH-dependent site-specific drug release was realized. The in vitro investigations confirmed that these promising GON/CS/CS-DMMA hybrids with the charge-reversible character possessed various merits including excellent encapsulation efficiency, high stability under physiological conditions, enhanced cellular uptake by HepG2 cells, and tunable intracellular chemotherapeutic agent release profiles, proving its capability as an intelligent anticancer agent nanocarrier with enhanced therapeutic effects. This smart GON/CS/CS-DMMA vehicle with the surface charge-reversible character may be used as a significant drug delivery system for cancer treatment.

A curcumin derived probe for colorimetric detection of azide ions in water

A curcumin based probe (CUC-P) having an active alkyne moiety has been synthesised for selective detection of azide (N₃⁻) ions in aqueous medium.