Functionalized Graphene Oxide as Nanocarrier for Loading and Delivery of Ellagic Acid

Ellagic acid-loaded soy protein isolate self-assembled particles: Characterization, stability, and antioxidant activity

The limited water solubility and bioactivity of lipophilic phytochemicals may be enhanced by delivery systems. Ellagic acid (EA) has antioxidant and anti-inflammatory properties, but low solubility and instability limit its use in the food industry. In this study, the pH-shift method was applied to encapsulate EA with soy protein isolate (SPI). The interaction, encapsulation, and protective potential of the EA-loaded soy SPI complexes (SPI-EA) were investigated. The fluorescence spectra results suggest that the reaction between SPI and EA is spontaneous, with hydrophobic interactions predominating. Binding of EA molecules quenches the intrinsic fluorescence of SPI, mainly static quenching, with a binding site involved in the binding process. The ultraviolet (UV)-visible spectroscopy of the SPI-EA complexes included the characteristic absorption peaks of both SPI and EA, and the scanning electron microscopy images further indicated that the EA had been successfully embedded in SPI. Fourier transform infrared spectroscopy illustrates that EA has significantly changed the secondary structure of the SPI, primarily in the form of a decreased content of α-helix structures and an increased content of β-sheet and random coil structures. The encapsulation efficiency of EA was concentration-dependent, up to 81.08%. The addition of EA reduces the size of SPI particles (d < 155 nm). In addition, the SPI-EA complex showed up to 81.05% and 96.46% 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity. TGA showed that the degradation temperature of SPI-EA complex could be extended up to 300°C. And by encapsulation of EA, the loss of EA under the action of UV light, heat treatment, and high concentration of salt ion sensitive environment can be reduced. PRACTICAL APPLICATION: Ellagic acid (EA), a natural bioactive with low water solubility and stability, can be enhanced by forming an inclusion complex with soy protein isolate (SPI). SPI-EA complex has broad potential applications in the food, beverage, and pharmaceutical industries. Multiple spectral analyses have contributed to our understanding of the formation and interaction mechanisms of the SPI-EA complex under pH-driven conditions. Stability assays have also aided in the development of dietary resources for EA.

Synthesis and Functionalization of Graphene Materials for Biomedical Applications: Recent Advances, Challenges, and Perspectives

Since its discovery in 2004, graphene is increasingly applied in various fields owing to its unique properties. Graphene application in the biomedical domain is promising and intriguing as an emerging 2D material with a high surface area, good mechanical properties, and unrivalled electronic and physical properties. This review summarizes six typical synthesis methods to fabricate pristine graphene (p-G), graphene oxide (GO), and reduced graphene oxide (rGO), followed by characterization techniques to examine the obtained graphene materials. As bare graphene is generally undesirable in vivo and in vitro, functionalization methods to reduce toxicity, increase biocompatibility, and provide more functionalities are demonstrated. Subsequently, in vivo and in vitro behaviors of various bare and functionalized graphene materials are discussed to evaluate the functionalization effects. Reasonable control of dose (<20 mg kg-1 ), sizes (50-1000 nm), and functionalization methods for in vivo application are advantageous. Then, the key biomedical applications based on graphene materials are discussed, coupled with the current challenges and outlooks of this growing field. In a broader sense, this review provides a comprehensive discussion on the synthesis, characterization, functionalization, evaluation, and application of p-G, GO, and rGO in the biomedical field, highlighting their recent advances and potential.

Chestnut Wood Mud as a Source of Ellagic Acid for Dermo-Cosmetic Applications

Ellagic acid (EA) has long been recognized as a very active antioxidant, anti-inflammatory, and antimicrobial agent. However, its low bioavailability has often hampered its applications in health-related fields. Here, we report a phospholipid vesicle-based controlled release system for EA, involving the exploitation of chestnut wood mud (CWM), an industrial by-product from chestnut tannin production, as a largely available and low-cost source of this compound. Two kinds of CWM with different particle size distributions, indicated as CWM-A and CWM-B (<100 and 32 µm, respectively), containing 5 ± 1% w/w EA, were incorporated into transfersomes. The latter were small in size (~100 nm), homogeneously dispersed, and negatively charged. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated up to three-fold improvement in the antioxidant properties of CWM upon incorporation into transfersomes. The kinetics of EA released under simulated physiological conditions were evaluated by UV-Vis spectroscopy and HPLC analysis. The best results were obtained with CWM-B (100% of EA gradually released after 37 days at pH 7.4). A stepwise increase in the antioxidant properties of the released material was also observed. Cell-based experiments confirmed the efficacy of CWM-B transfersomes as antioxidant agents in contrasting photodamage.

Multifunctional graphene oxide nanoparticles for drug delivery in cancer

Recent advancements in nanotechnology have enabled us to develop sophisticated multifunctional nanoparticles or nanosystems for targeted diagnosis and treatment of several illnesses, including cancers. To effectively treat any solid tumor, the therapy should preferably target just the malignant cells/tissue with minor damage to normal cells/tissues. Graphene oxide (GO) nanoparticles have gained considerable interest owing to their two-dimensional planar structure, chemical/mechanical stability, excellent photosensitivity, superb conductivity, high surface area, and good biocompatibility in cancer therapy. Many compounds have been functionalized on the surface of GO to increase their biological applications and minimize cytotoxicity. The review presents an overview of the physicochemical characteristics, strategies for various modifications, toxicity and biocompatibility of graphene and graphene oxide, current trends in developing GO-based nano constructs as a drug delivery cargo and other biological applications, including chemo-photothermal therapy, chemo-photodynamic therapy, bioimaging, and theragnosis in cancer. Further, the review discusses the challenges and opportunities of GO, GO-based nanomaterials for the said applications. Overall, the review focuses on the therapeutic potential of strategically developed GO nanomedicines and comprehensively discusses their opportunities and challenges in cancer therapy.

Promising Therapeutic Strategies for Colorectal Cancer Treatment Based on Nanomaterials

Colorectal cancer (CRC) is a global health problem responsible for 10% of all cancer incidences and 9.4% of all cancer deaths worldwide. The number of new cases increases per annum, whereas the lack of effective therapies highlights the need for novel therapeutic approaches. Conventional treatment methods, such as surgery, chemotherapy and radiotherapy, are widely applied in oncology practice. Their therapeutic success is little, and therefore, the search for novel technologies is ongoing. Many efforts have focused recently on the development of safe and efficient cancer nanomedicines. Nanoparticles are among them. They are uniquewith their properties on a nanoscale and hold the potential to exploit intrinsic metabolic differences between cancer and healthy cells. This feature allows them to induce high levels of toxicity in cancer cells with little damage to the surrounding healthy tissues. Graphene oxide is a promising 2D material found to play an important role in cancer treatments through several strategies: direct killing and chemosensitization, drug and gene delivery, and phototherapy. Several new treatment approaches based on nanoparticles, particularly graphene oxide, are currently under research in clinical trials, and some have already been approved. Here, we provide an update on the recent advances in nanomaterials-based CRC-targeted therapy, with special attention to graphene oxide nanomaterials. We summarise the epidemiology, carcinogenesis, stages of the CRCs, and current nanomaterials-based therapeutic approaches for its treatment.

Polymer grafted magnetic graphene oxide as a potential nanocarrier for pH-responsive delivery of sparingly soluble quercetin against breast cancer cells

In this work, polymer grafted magnetic graphene oxide (GO-PVP-Fe3O4) was successfully synthesized for efficient delivery of anticancer drug. Firstly, GO was functionalized with the hydrophilic and biocompatible polymer polyvinylpyrrolidone (PVP) and then grafted with magnetic nanoparticles (Fe3O4) through an easy and effective chemical co-precipitation method. Quercetin (QSR) as an anticancer drug was loaded onto the surface of GO-PVP-Fe3O4 via non-covalent interactions. The drug loading capacity was as high as 1.69 mg mg-1 and the synthesized magnetic nanocarrier shows pH-responsive controlled release of QSR. The cellular cytotoxicity of the synthesized nanocarrier with and without drugs was investigated in human breast cancer MDA MB 231 cells and their effects compared on non-tumorigenic epithelial HEK 293T cells. These results reveal that the drug loaded GO-PVP-Fe3O4 nanohybrid was found to be more toxic than the free drug towards MDA MB 231 cells and exhibits biocompatibility towards HEK 293T cells. Overall, a smart drug delivery system including polymer grafted magnetic graphene oxide as a pH-responsive potential nanocarrier could be beneficial for targeted drug delivery, controlled by an external magnetic field as an advancement in chemotherapy against cancer.

Cell viability and electrical response of breast cancer cell treated in aqueous graphene oxide solution deposition on interdigitated electrode

Breast cancer is one of the most reported cancers that can lead to death. Despite the advances in diagnosis and treatment procedures, the possibility of cancer recurrences is still high in many cases. With that in consideration, researchers from all over the world are showing interest in the unique features of Graphene oxide (GO), such as its excellent and versatile physicochemical properties, to explore further its potential and benefits towards breast cancer cell treatment. In this study, the cell viability and electrical response of GO, in terms of resistivity and impedance towards the breast cancer cells (MCF7) and normal breast cells (MCF10a), were investigated by varying the pH and concentration of GO. Firstly, the numbers of MCF7 and MCF10a were measured after being treated with GO for 24 and 48 h. Next, the electrical responses of these cells were evaluated by using interdigitated gold electrodes (IDEs) that are connected to an LCR meter. Based on the results obtained, as the pH of GO increased from pH 5 to pH 7, the number of viable MCF7 cells decreased while the number of viable MCF10a slightly increased after the incubation period of 48 h. Similarly, the MCF7 also experienced higher cytotoxicity effects when treated with GO concentrations of more than 25 µg/mL. The findings from the electrical characterization of the cells observed that the number of viable cells has corresponded to the impedance of the cells. The electrical impedance of MCF7 decreased as the number of highly insulating viable cell membranes decreased. But in contrast, the electrical impedance of MCF10a increased as the number of highly insulating viable cell membranes increased. Hence, it can be deduced that the GO with higher pH and concentration influence the MCF7 cancer cell line and MCF10a normal breast cell.

A potentially valuable nano graphene oxide/USPIO tumor diagnosis and treatment system

Due to increased requirements for precision cancer treatment, cancer chemotherapy and combination therapies have gradually developed in the direction of diagnosis and treatment integration. In this study, a non-toxic nano carrier that demonstrates integrated MRI signal enhancing performance, as well as better chemotherapy and photothermal conversion performance, was prepared and characterized. Furthermore, the carrier was used to construct an integrated system of tumor diagnosis and treatment. Our in vitro studies showed that this system has a considerable inhibition effect on tumor cells during the treatment of chemotherapy when combined with PTT, and in vivo studies showed that the system could improve the MRI signal of the tumor site with application of a safe dosage. Thus, this system based on NGO/USPIO has the potential to be a multi-functional nano drug delivery system integrating diagnosis and treatment benefits and applications that are worthy of further research.

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.

Recent progress of graphene oxide-based multifunctional nanomaterials for cancer treatment

Background

In the last decade, graphene oxide-based nanomaterials, such as graphene oxide (GO) and reduced graphene oxide (rGO), have attracted more and more attention in the field of biomedicine. Due to the versatile surface functionalization, ultra-high surface area, and excellent biocompatibility of graphene oxide-based nanomaterials, which hold better promise for potential applications than among other nanomaterials in biomedical fields including drug/gene delivery, biomolecules detection, tissue engineering, especially in cancer treatment.

Results

Here, we review the recent progress of graphene oxide-based multifunctional nanomaterials for cancer treatment. A comprehensive and in-depth depiction of unique property of graphene oxide-based multifunctional nanomaterials is first interpreted, with particular descriptions about the suitability for applying in cancer therapy. Afterward, recently emerging representative applications of graphene oxide-based multifunctional nanomaterials in antitumor therapy, including as an ideal carrier for drugs/genes, phototherapy, and bioimaging, are systematically summarized. Then, the biosafety of the graphene oxide-based multifunctional nanomaterials is reviewed.

Conclusions

Finally, the conclusions and perspectives on further advancing the graphene oxide-based multifunctional nanomaterials toward potential and versatile development for fundamental researches and nanomedicine are proposed.

Graphic abstract

Recent advances in graphene-family nanomaterials for effective drug delivery and phototherapy

INTRODUCTION

Owing to the unique properties of graphene, including large specific surface area, excellent thermal conductivity, and optical absorption, graphene-family nanomaterials (GFNs) have attracted extensive attention in biomedical applications, particularly in drug delivery and phototherapy.

AREAS COVERED

In this review, we point out several challenges involved in the clinical application of GFNs. Then, we provide an overview of the most recent publications about GFNs in biomedical applications, including diverse strategies for improving the biocompatibility, specific targeting and stimuli-responsiveness of GFNs for drug delivery, codelivery of drug and gene, photothermal therapy, photodynamic therapy, and multimodal combination therapy.

EXPERT OPINION

Although the application of GFNs is still in the preclinical stage, rational modification of GFNs with functional elements or making full use of GFNs-based multimodal combination therapy might show great potential in biomedicine for clinical application.

Graphene Oxide as a Nanocarrier for Biochemical Molecules: Current Understanding and Trends

The development of an advanced and efficient drug delivery system with significant improvement in its efficacy and enhanced therapeutic value is one of the critical challenges in modern medicinal biology. The integration of nanomaterial science with molecular and cellular biology has helped in the advancement and development of novel drug delivery nanocarrier systems with precision and decreased side effects. The design and synthesis of nanocarriers using graphene oxide (GO) have been rapidly growing over the past few years. Due to its remarkable physicochemical properties, GO has been extensively used in efforts to construct nanocarriers with high specificity, selectivity, and biocompatibility, and low cytotoxicity. The focus of this review is to summarize and address recent uses of GO-based nanocarriers and the improvements as efficient drug delivery systems. We briefly describe the concepts and challenges associated with nanocarrier systems followed by providing critical examples of GO-based delivery of drug molecules and genes. Finally, the review delivers brief conclusions on the current understanding and prospects of nanocarrier delivery systems.

Recent progress of graphene oxide as a potential vaccine carrier and adjuvant

Vaccine is one of the most effective strategies for preventing and controlling infectious diseases and some noninfectious diseases, especially cancers. Adjuvants and carriers have been appropriately added to the vaccine formulation to improve the immunogenicity of the antigen and induce long-lasting immunity. However, there is an urgent need to develop new all-purpose adjuvants because some adjuvants approved for human use have limited functionality. Graphene oxide (GO), widely employed for the delivery of biomolecules, excels in loading and delivering antigen and shows the potentiality of activating the immune system. However, GO aggregates in biological liquid and induces cell death, and it also exhibits poor biosolubility and biocompatibility. To address these limitations, various surface modification protocols have been employed to integrate aqueous compatible substances with GO to effectively improve its biocompatibility. More importantly, these modifications render functionalized-GO with superior properties as both carriers and adjuvants. Herein, the recent progress of physicochemical properties and surface modification strategies of GO for its application as both carriers and adjuvants is reviewed. STATEMENT OF SIGNIFICANCE: Due to its unique physicochemical properties, graphene oxide is widely employed in medicine for purposes of photothermal treatment of cancer, drug delivery, antibacterial therapy, and medical imaging. Our work describes the surface modification of graphene oxide and for the first time summarizes that functionalized graphene oxide serves as a vaccine carrier and shows significant adjuvant activity in activating cellular and humoral immunity. In the future, it is expected to be introduced into vaccine research to improve the efficacy of vaccines.

Comprehensive Review on Graphene Oxide for Use in Drug Delivery System

Motivated by the accomplishment of carbon nanotubes (CNTs), graphene and graphene oxide (GO) has been widely investigated in the previous studies as an innovative medication nanocarrier for the loading of a variety of therapeutics as well as anti-cancer medications, poor dissolvable medications, antibiotics, antibodies, peptides, DNA, RNA and genes. Graphene provides the ultra-high drug-loading efficiency due to the wide surface area. Graphene and graphene oxide have been widely investigated for biomedical applications due to their exceptional qualities: twodimensional planar structure, wide surface area, chemical and mechanical constancy, sublime conductivity and excellent biocompatibility. Due to these unique qualities, GO applications provide advanced drug transports frameworks and transports of a broad range of therapeutics. In this review, we discussed the latest advances and improvements in the uses of graphene and GO for drug transport and nanomedicine. Initially, we have described what is graphene and graphene oxide. After that, we discussed the qualities of GO as a drug carrier, utilization of GO in drug transport applications, targeted drug transport, transport of anticancer medications, chemical control medicine releasee, co-transport of different medications, comparison of GO with CNTs, nano-graphene for drug transport and at last, we have discussed the graphene toxicity. Finally, we draw a conclusion of current expansion and the potential outlook for the future.

Cetylpyridinium bromide/montmorillonite-graphene oxide composite with good antibacterial activity

In this study, a cetylpyridinium bromide (CPB)/montmorillonite-graphene oxide (GM) composite (GM-CPB) was prepared by loading CPB in a carrier of GM. The chemical structure, elemental composition, morphology, thermogravimetric analysis, antibacterial activity, sustained release property and cytotoxicity were analyzed. The loading rate of CPB in a GM carrier was higher than that of the graphene oxide (GO) carrier under the same loading condition. The antibacterial activity and sustained release performance of GM-CPB were also better than that of GO-CPB; furthermore, GM-CPB showed lower cytotoxicity than CPB.

Recent Advances on Graphene Quantum Dots for Bioimaging Applications

Being a zero-dimensional (0D) nanomaterial of the carbon family, graphene quantum dots (GQDs) showed promising biomedical applications owing to their ultra-small size, non-toxicity, biocompatibility, excellent photo stability, tunable fluorescence, and water solubility, etc., thus capturing a considerable attention in biomedical field. This review summarizes the recent advances made in the research field of GQDs and place special emphasis on their bioimaging applications. We briefly introduce the synthesis strategies of GQDs, including top-down and bottom-up strategies. The bioimaging applications of GQDs are also discussed in detail, including optical [fluorescence (FL)], two-photon FL, magnetic resonance imaging (MRI), and dual-modal imaging. In the end, the challenges and future prospects to advance the clinical bioimaging applications of GQDs have also been addressed.

Formulation Strategies to Improve Oral Bioavailability of Ellagic Acid

Ellagic acid, a polyphenolic compound present in fruit and berries, has recently been the object of extensive research for its antioxidant activity, which might be useful for the prevention and treatment of cancer, cardiovascular pathologies, and neurodegenerative disorders. Its protective role justifies numerous attempts to include it in functional food preparations and in dietary supplements, and not only to limit the unpleasant collateral effects of chemotherapy. However, ellagic acid use as a chemopreventive agent has been debated because of its poor bioavailability associated with low solubility, limited permeability, first pass effect, and interindividual variability in gut microbial transformations. To overcome these drawbacks, various strategies for oral administration including solid dispersions, micro and nanoparticles, inclusion complexes, self-emulsifying systems, and polymorphs were proposed. Here, we listed an updated description of pursued micro and nanotechnological approaches focusing on the fabrication processes and the features of the obtained products, as well as on the positive results yielded by in vitro and in vivo studies in comparison to the raw material. The micro and nanosized formulations here described might be exploited for pharmaceutical delivery of this active, as well as for the production of nutritional supplements or for the enrichment of novel foods.

Nanocarriers Used Most in Drug Delivery and Drug Release: Nanohydrogel, Chitosan, Graphene, and Solid Lipid

Over the past few years, nanocarriers have become an ideal solution for safe and efficient drug delivery and release. This is mainly due to the extraordinary characteristics that nanomaterials exhibit when compared with their larger scaled forms. A variety of these carriers are more popular due to their high biocompatibility, ensuring greater efficacy especially in cancer treatments. Nanocrystal, liposomal, and micelle designs of these materials as nanocarriers for drug delivery and release have been extensively researched throughout the past 50 years. Successful applications have not only ensured a greater focus on therapeutic development but also created a new solution available in the pharmaceutical market. Herein, a brief review of research studies focused on nanocarrier materials and designs to achieve superior benefits of drugs for disease treatments is presented. Nanohydrogels, chitosan, graphene oxide, and solid lipid nanoparticle nanocarrier designs and applications are selectively given due to the great attention they have gained from being highly biocompatible and easy-to-manipulate nanocarrier options from organic and inorganic nanocarrier materials. Each summary exhibits the progress that has been achieved to date. With greater understanding of the current state in the development process of these nanomaterials, there is a rising chance to provide better treatment to patients, which is a desperate need in pharmaceutical technologies.

Progress and Prospects of Graphdiyne-Based Materials in Biomedical Applications

Graphdiyne is a new member of the family of carbon-based nanomaterials that possess two types of carbon atoms, sp- and sp² -hybridized carbon atoms. As a novel 2D carbon-based nanomaterial with unique planar structure, such as uniformly distributed nanopores and large conjugated structure, graphdiyne has shown many fascinating properties in mechanics, electronics, and optics since it was first experimentally synthesized in 2010. Up to now, graphdiyne and its derivatives have been reported to be successfully applied in many areas, such as catalysis, energy, environment, and biomedicine, due to these excellent properties. Herein, the current research progress of graphdiyne-based materials in biomedical fields is summarized, including biosensing, biological protection, cancer therapy, tissue engineering, etc. The advantages of graphdiyne and its derivatives are presented and compared with other carbon-based materials. Considering the potential biomedical and clinical applications of graphdiyne-based materials, the toxicity and biocompatibility are also discussed based on current studies. Finally, future perspectives and possible biomedical applications of graphdiyne-based materials are also discussed.

Two dimensional carbon based nanocomposites as multimodal therapeutic and diagnostic platform: A biomedical and toxicological perspective

Graphene based nanocomposites have revolutionized cancer treatment, diagnosis and imaging owing to its good compatibility, elegant flexibility, high surface area, low mass density along with excellent combined additive effect of graphene with other nanomaterials. This review inculcates the type of graphene based nanocomposites and their fabrication techniques to improve its properties as photothermal and theranostic platform. With decades' efforts, many significant breakthroughs in the method of synthesis and characterization in addition to various functionalization options of graphene based nanocomposite have paved a solid foundation for their potential applications in the cancer therapy. This work intends to provide a thorough, up-to-date holistic discussion on correlation of breakthroughs with their biomedical applications and illustrate how to utilize these breakthroughs to address long-standing challenges in the clinical translation of nanomedicines. This review also emphasizes on graphene based nanocomposites based toxicity concerns pertaining to delivery platforms.

Polyethylene glycol (PEG) decorated graphene oxide nanosheets for controlled release curcumin delivery

Nowadays, the use of nanostructures in various medical and biological fields such as drug delivery in cancer treatment is increasing. Among the nanostructures, graphene oxide (GO) is an excellent candidate for drug delivery application because of its unique properties. For more stability, GO can bind with various polymers by its carboxyl, hydroxyl and epoxy functional groups. In this study, firstly GO synthesized by the improved Hummers chemical method and then polyethylene glycol polymer was conjugated to it by using EDC/NHS catalyst. Finally, curcumin (Cur) as anti-cancer drug has been loaded onto the PEGylated graphene oxide (GO-PEG). Next, curcumin loaded onto PEGylated graphene oxide (GO-PEG-Cur) were evaluated by using ultraviolet, Fourier transform infrared spectroscopy, differential scanning calorimeter, atomic microscopic force and dynamic light scattering. The amount of loaded drug was calculated about 4.5% with the help of the standard curcumin curve and UV/Vis spectrometer. Also, the result of release shows that maximum drug release rate for this nanocarrier in pH 5.5 and 7.4 was measured 50% and 60%, respectively, after 96 hours. The results showed that the zeta-potential analysis of GO-PEG-Cur was about -13.9 mV that expresses a negative surface charge for produced nanocarrier.

Graphene-Based Nanocomposites for Neural Tissue Engineering

Graphene has made significant contributions to neural tissue engineering due to its electrical conductivity, biocompatibility, mechanical strength, and high surface area. However, it demonstrates a lack of biological and chemical cues. Also, it may cause potential damage to the host body, limiting its achievement of efficient construction of neural tissues. Recently, there has been an increasing number of studies showing that combining graphene with other materials to form nano-composites can provide exceptional platforms for both stimulating neural stem cell adhesion, proliferation, differentiation and neural regeneration. This suggests that graphene nanocomposites are greatly beneficial in neural regenerative medicine. In this mini review, we will discuss the application of graphene nanocomposites in neural tissue engineering and their limitations, through their effect on neural stem cell differentiation and constructs for neural regeneration.

Applications of graphene oxide in case of nanomedicines and nanocarriers for biomolecules: review study

In this Review article, recent progress in matter of graphene oxide (GO) synthesis and its functionalization via a vast range of materials, including small molecules, polymers, and biomolecules, were reported and systematically summarized in order to overcome the inherent drawbacks of GO nanocarriers and thereby make these nanocarriers suitable for delivering chemotherapeutic agents, genes, and short interfering RNAs. Briefly, this work describes current strategies for the large scale production of GO and modification of graphene-based nanocarriers surfaces through practical chemical approaches, improving their biocompatibility and declining their toxicity. It also describes the most relevant cases of study suitable to demonstrate the role of graphene and graphene derivatives (GD) as nanocarrier for anti-cancer drugs and genes (e.g. miRNAs). Moreover, the controlled release mechanisms within the cell compartments and blood pH for targeted therapeutics release in the acidic environment of tumor cells or in intracellular compartments are mentioned and explored.

Graphene-based drug delivery systems in tissue engineering and nanomedicine

The time and dosage form of graphene derivatives have been found to determine therapeutic and toxic windows in several cell lines and preclinical models. The enhanced biological action of graphene derivatives is made possible by altering the chemistry of native materials via surface conjugation, or by changing the oxidation state. The high level of chemical reactivity vested in the planar structure of graphene can be used to load various drugs and biomolecules with maximum radical scavenging effect. The integration of graphene and polymers brings electrical conductivity to scaffolds, making them ideal for cardiac or neuronal tissue engineering. Drawbacks associated with graphene-based materials for biomedical applications include defect-free graphene formation and heteroatom contamination during synthesis process; reduced availability of sp² hybridized carbon centers due to serum proteins masking; and poor availability of data pertaining to in vivo clearance of graphene-based formulations. Personalized medicine is an emerging area of alternative treatments, which in combination with graphene-based nanobiomaterials, has revolutionary potential for the development of individualized nanocarriers to treat highly challenging diseases.

A Review on Graphene-Based Nanomaterials in Biomedical Applications and Risks in Environment and Health

Graphene-based nanomaterials (GBNs) have attracted increasing interests of the scientific community due to their unique physicochemical properties and their applications in biotechnology, biomedicine, bioengineering, disease diagnosis and therapy. Although a large amount of researches have been conducted on these novel nanomaterials, limited comprehensive reviews are published on their biomedical applications and potential environmental and human health effects. The present research aimed at addressing this knowledge gap by examining and discussing: (1) the history, synthesis, structural properties and recent developments of GBNs for biomedical applications; (2) GBNs uses as therapeutics, drug/gene delivery and antibacterial materials; (3) GBNs applications in tissue engineering and in research as biosensors and bioimaging materials; and (4) GBNs potential environmental effects and human health risks. It also discussed the perspectives and challenges associated with the biomedical applications of GBNs.

Functionalized graphene oxides for drug loading, release and delivery of poorly water soluble anticancer drug: A comparative study

In this work, the modification of graphene oxides (GOs) have been done with hydrophilic and biodegradable polymer, polyvinylpyrrolidone (PVP) and other excipient β -cyclodextrin (β-CD) through covalent functionalization for efficient loading and compatible release of sparingly water soluble aromatic anticancer drug SN-38 (7-ethyl-10-hydroxy camptothecin). The drug was loaded onto both GO-PVP and GO-β-CD through the π-π interactions.The release of drug from both the nanocarriers were analyzed in different pH medium of pH 7 (water, neutral medium), pH 5 (acidic buffer) and pH 12 (basic buffer). The loading capacity and the cell killing activity of SN-38 loaded on functionalized GO were investigated comprehensively in human breast cancer cells MCF-7.Our findings shown that the cytotoxicity of SN-38 loaded to the polymer modified GO was comparatively higher than free SN-38. In particular, SN-38 loaded GO-PVP nanocarrier has more cytotoxic effect than GO-β-CD nanocarrier against MCF-7 cells, indicating that SN-38 loaded GO-PVP nanocarrier can be used as promising material for drug delivery and biological applications.

Isolation of ellagic acid from pomegranate peel extract by hydrophobic interaction chromatography using graphene oxide grafted cotton fiber adsorbent

Ellagic acid, a natural polyphenol, was isolated from pomegranate peel extract by hydrophobic interaction using graphene oxide grafted cotton fiber as a stationary adsorbent. The grafted graphene oxide moieties served as hydrophobic interaction-binding sites for ellagic acid adsorption. The graphene oxide grafted cotton fiber was made into a membrane-like sheet in order to complete ellagic acid purification by using a binding-elution mode. The effects of operational parameters, such as the composition of the binding buffer/elution buffer, buffer pH, and buffer concentration, on the isolation process were investigated. It was found that 5 mmol/L sodium carbonate aqueous solution is a proper-binding buffer, and sodium hydroxide aqueous solution ranging from 0.04 to 0.06 mol/L is a suitable elution solution for ellagic acid purification. Under the optimized condition, the purity of ellagic acid increased significantly from 7.5% in the crude extract to 75.0-80.0%. The pH value was found to be a key parameter that determines the adsorption and desorption of ellagic acid. No organic solvent is involved in the entire purification process. Thus, a simple and environmentally friendly method is established for ellagic acid purification using a graphene oxide-modified biodegradable and bio-sourced fibrous adsorbent.

Semiconductorversusgraphene quantum dots as fluorescent probes for cancer diagnosis and therapy applications

This review provides a comparison of optical, chemical and biocompatibility properties of graphene and semiconductor quantum dots as fluorescent probes.

Thermoresponsive graphene oxide - starch micro/nanohydrogel composite as biocompatible drug delivery system

Introduction: Stimuli-responsive hydrogels, which indicate a significant response to the environmental change (e.g., pH, temperature, light, …), have potential applications for tissue engineering, drug delivery systems, cell therapy, artificial muscles, biosensors, etc. Among the temperature-responsive materials, poly (N-isopropylacrylamide) (PNIPAAm) based hydrogels have been widely developed and their properties can be easily tailored by manipulating the properties of the hydrogel and the composite material. Graphene oxide (GO), as a multifunctional and biocompatible nanosheet, can efficiently improve the mechanical strength and response rate of PNIPAAm-based hydrogels. Here, hydrogel composites (HCs) of PNIPAAm with GO was developed using the modified starch as a biodegradable cross-linker. Methods: Micro/nanohydrogel composites were synthesized by free radical polymerization of NIPAAm in the suspension of different feed ratio of GO using maleate-modified starch (St-MA) as cross-linker and Tetrakis (hydroxymethyl) phosphonium chloride (THPC) as a strong oxygen scavenger. The HCs were characterized by FT-IR, DSC, TGA, SEM, and DLS. Also, the phase transition, swelling/deswelling behavior, hemocompatibility and biocompatibility of the synthesized HCs were investigated. Results: The thermal stability, phase transition temperature and internal network crosslinking of HCs increases with increasing of the GO feed ratio. Also, the swelling/deswelling, hemolysis, and MTT assays studies confirmed that the HCs are a fast response, hemocompatible and biocompatible materials. Conclusion: The employed facile approach for the synthesis of HCs yields an intelligent material with great potential for biomedical applications.

The application of graphene oxidized combining with decellularized scaffold to repair of sciatic nerve injury in rats

This paper combined the decellularized scaffold of sciatic nerve of rats with graphene oxidized (GO), studied and facilitated the regeneration of sciatic nerve of rats, and provided the basis for the clinical application of nanomaterials. GO was prepared through improving Hammer’s Method. Fourier Infrared Spectrum was used to scan and detect the functional groups in GO of sample by using the pellet method, the microcosmic morphological appearance of GO was observed by using the scanning electron microscope. The GO/decellularized scaffold were prepared and operation bridging of injured sciatic nerve was conducted by using the oscillation mixing method. BL-420F Biofunctional Experiment System was used to detect nerve action potential and the maximum tension value of muscles, and the fiber structure of nerve was observed under H-7650 Transmission Electron Microscope (TEM). Scanning electron microscope observed that GO presented a folded and curly single-layer sheet structure. It was soluble in water through ultrasound, brownish, the Fourier Transform Infrared Spectrometer detected the absorption peaks of carbonyl, hydroxy and carboxy, proving that the surface of GO material had many functional groups containing oxygen. Decellularized scaffold combining with GO was applied to repair injury of sciatic nerve, the nerve action potential, maximum tension value of muscle, wet weight value of gastrocnemius, thickness of gastrocnemius, thickness of myelin sheath and diameter of axon of the decellularized scaffold combining with GO group were obviously higher than the decellularized scaffold group and the self-rotating group, approaching to the normal value. All the data were represented by means ± standard deviation (x¯±s) and processed by adopting SPSS 11.0 software. Comparisons among groups were analyzed by variance, and the comparison of two means was detected by student t. The detection level adopted α = 0.05, when P < 0.05, it could be considered that there were significant differences. GO could combine with the biomaterial-decellularized scaffold to repair the injury of sciatic nerve and facilitate the regeneration of injured nerve. This provided new thoughts and theoretical & experimental bases for nanomaterials to be applied to clinic treatment of repair of nerve injury.

Phosphorylcholine oligomer-grafted graphene oxide for tumor-targeting doxorubicin delivery

Phosphorylcholine oligomer-grafted, folic acid-labeled and doxorubicin-loaded graphene oxide was found to be a potential versatile platform for biomarker-directed drug delivery with optimal biocompatibility.

Improved Anticancer Photothermal Therapy Using the Bystander Effect Enhanced by Antiarrhythmic Peptide Conjugated Dopamine-Modified Reduced Graphene Oxide Nanocomposite

Despite tremendous efforts toward developing novel near-infrared (NIR)-absorbing nanomaterials, improvement in therapeutic efficiency remains a formidable challenge in photothermal cancer therapy. This study aims to synthesize a specific peptide conjugated polydopamine-modified reduced graphene oxide (pDA/rGO) nanocomposite that promotes the bystander effect to facilitate cancer treatment using NIR-activated photothermal therapy. To prepare a nanoplatform capable of promoting the bystander effect in cancer cells, we immobilized antiarrhythmic peptide 10 (AAP10) on the surface of dopamine-modified rGO (AAP10-pDA/rGO). Our AAP10-pDA/rGO could promote the bystander effect by increasing the expression of connexin 43 protein in MCF-7 breast-cancer cells. Because of its tremendous ability to absorb NIR absorption, AAP10-pDA/rGO offers a high photothermal effect under NIR irradiation. This leads to a massive death of MCF-7 cells via the bystander effect. Using tumor-bearing mice as the model, it is found that NIR radiation effectively ablates breast tumor in the presence of AAP10-pDA/rGO and inhibits tumor growth by ≈100%. Therefore, this research integrates the bystander and photothermal effects into a single nanoplatform in order to facilitate an efficient photothermal therapy. Furthermore, our AAP10-pDA/rGO, which exhibits both hyperthermia and the bystander effect, can prevent breast-cancer recurrence and, therefore, has great potential for future clinical and research applications.

Recent Advances in Anticancer Activities and Drug Delivery Systems of Tannins

Tannins, polyphenols in medicinal plants, have been divided into two groups of hydrolysable and condensed tannins, including gallotannins, ellagitannins, and (-)-epigallocatechin-3-gallate (EGCG). Potent anticancer activities have been observed in tannins (especially EGCG) with multiple mechanisms, such as apoptosis, cell cycle arrest, and inhibition of invasion and metastases. Furthermore, the combinational effects of tannins and anticancer drugs have been demonstrated in this review, including chemoprotective, chemosensitive, and antagonizing effects accompanying with anticancer effect. However, the applications of tannins have been hindered due to their poor liposolubility, low bioavailability, off-taste, and shorter half-life time in human body, such as EGCG, gallic acid, and ellagic acid. To tackle these obstacles, novel drug delivery systems have been employed to deliver tannins with the aim of improving their applications, such as gelatin nanoparticles, micelles, nanogold, liposomes, and so on. In this review, the chemical characteristics, anticancer properties, and drug delivery systems of tannins were discussed with an attempt to provide a systemic reference to promote the development of tannins as anticancer agents.

Controlled release and long-term antibacterial activity of reduced graphene oxide/quaternary ammonium salt nanocomposites prepared by non-covalent modification

In order to control the long-term antibacterial property of quaternary ammonium salts, dodecyl dimethyl benzyl ammonium chloride (rGO-1227) and rGO-bromohexadecyl pyridine (rGO-CPB) were self-assembled on surfaces of reduced graphene oxide (rGO) via π-π interactions. The obtained rGO-1227 and rGO-CPB nanocompounds were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM).The antibacterial activities were evaluated on Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Both rGO-CPB and rGO-1227 reduced the cytotoxicity of the pure antimicrobial agents and presented strong antimicrobial properties. Especially, CPB could be loaded efficiently on the surface of rGO via π-π conjugate effect, which resulted in a nanocomposite presenting a long-term antibacterial capability due to the more important quantity of free π electrons compared to that of 1227. When comparing the advantages of both prepared nanocomposites, rGO-CPB displayed a better specific-targeting capability and a longer-term antibacterial property.

Graphene-based nanosheets for delivery of chemotherapeutics and biological drugs

Graphene-based nanosheets (GNS), including graphenes, graphene oxides and reduced graphene oxides, have properties suitable for delivery of various molecules. With their two-dimensional structures, GNS provide relatively high surface areas and capacity for non-covalent π-π stacking and hydrophobic interactions with various drug molecules. Currently, GNS-based delivery applications extend to chemotherapeutics as well as biological drugs, including nucleic acid drugs, proteins, and peptides. Surfaces of GNS have been modified with various polymers, such as polyethylene glycol and biopolymers, which enhance biocompatibility and increase drug loading. Anticancer drugs are prominent among chemotherapeutic agents tested, and have been loaded onto GNS with relatively high loading capacities compared with other nanocarriers. For enhanced distribution to specific tissues, GNS have been covalently or non-covalently modified with targeting ligands, including folic acid, transferrins, and others. In this review, we cover the current status of GNS for delivery of anticancer chemotherapeutics and biological drugs, with a focus on nucleic acid drugs. Remaining challenges for the application of GNS for drug-delivery systems and future perspectives are also addressed.

Targeted Near-Infrared Fluorescent Turn-on Nanoprobe for Activatable Imaging and Effective Phototherapy of Cancer Cells

A novel and green multifunctional nanoplatform as a nanocarrier for drug delivery, cell imaging, and phototherapy has been engineered. The nanoplatform is composed of stabilized carbon spheres (CSs) as cores, a coated polydopamine (PDA) shell, targeted folic acid (FA), and the loaded anticancer drug indocyanine green (ICG), obtaining CSs@PDA-FA@ICG nanocomposites (NCs). The biocompatible PDA shell provided a high fluorescence quenching efficiency and a surface rich in functional groups for anchoring FA for targeting cancer cells. Aromatic ICG could be effectively loaded into the CSs@PDA-FA system via hydrophobic interactions and π-π stacking with a loading efficiency of 58.9%. Notably, the activated NIR fluorescence in an intracellular environment made CSs@PDA-FA@ICG a sensitive "OFF" to "ON" nanoprobe that can be used for NIR imaging. Moreover, compared to ICG alone, the CSs@PDA-FA@ICG NCs could induce efficient photoconversion for simultaneous synergetic photodynamic therapy (PDT) and photothermal therapy (PTT) under a single NIR laser irradiation. The results demonstrated that CSs@PDA-FA@ICG NCs as a targeted and activated nanoplatform provide new opportunities to facilitate the accurate diagnosis of cancer and enhanced treatment efficacy. This work stimulates more interest in the design of the facile surface functionalization strategy to construct other multifunctional nanocomposites, such as nanotubes and nanorods.

Hybridization of graphene sheets with polyethylene terephthalate through the process of in situ polymerization aided by ultrasound

A new methodology to prepare hybrid graphene–polyethylenterephthalate nanocomposites by ultrasonication is reported.

Potentiating effect of graphene nanomaterials on aromatic environmental pollutant-induced cytochrome P450 1A expression in the topminnow fish hepatoma cell line PLHC-1

Graphene and its derivatives are an emerging class of carbon nanomaterial with great potential for a broad range of industrial and consumer applications. However, their increasing production and use is expected to result in release of nano-sized graphene platelets into the environment, where they may interact with chemical pollutants modifying their fate and toxic potential. The objective of this study was to assess whether graphene nanoplatelets can act as vector for aromatic environmental pollutants increasing their cellular uptake and associated hazardous effects in vitro. For this purpose, cell cultures of the topminnow fish (Poeciliopsis lucida) hepatoma cell line PLHC-1 were simultaneously (and successively) exposed to graphene nanoplatelets (graphene oxide (GO) or carboxyl graphene (CXYG)) and an aryl hydrocarbon receptor (AhR) agonist (β-naphthoflavone (β-NF), benzo(k)fluoranthene (BkF) or 3,3',4,4',5,5'-hexachlorobiphenyl (PCB169)). Following exposure cytochrome P450 1A (Cyp1A) induction was assessed by measuring cyp1A mRNA expression levels using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and Cyp1A-dependent ethoxyresorufin-O-deethylase (EROD) activity. It was observed that pre- and co-exposure of cells to GO and CXYG nanoplatelets had a potentiating effect on β-NF, BkF, and PCB169-dependent Cyp1A induction suggesting that graphene nanoplatelets increase the effective concentration of AhR agonists by facilitating their passive diffusion into the cells by damaging the cells' plasma membrane and/or by transporting them over the plasma membrane via a Trojan horse-like mechanism. The results demonstrate the existence of combination effects between nanomaterials and environmental pollutants and stress the importance of considering these effects when evaluating their respective hazard.