Recent Advances in the Synthesis of Graphene-Based Nanomaterials for Controlled Drug Delivery

A Narrative Review on the Promising Potential of Graphene in Vaccine Design: Evaluating the Benefits and Drawbacks of Carbon Nanoplates in Nanovaccine Production

Graphene, a two-dimensional material consisting of a single layer of carbon atoms arranged in a honeycomb lattice, has shown great potential in various fields, including biomedicine. When it comes to vaccine development, graphene can offer several advantages due to its unique properties. Potential applications of graphene in vaccine development include improved vaccine delivery, adjuvant properties, improved vaccine stability, improved immune response, and biosensing capabilities. Although graphene offers many potential benefits in vaccine development, there are also some drawbacks and challenges associated with its use. Although graphene shows promising potential for vaccine development, overcoming the challenges and limitations associated with its use is critical to realizing its full potential in the field of immunization. Further research and development efforts are needed to overcome these drawbacks and take advantage of graphene for improved vaccine formulations. In this review, we focus on the advantages and disadvantages of graphene for vaccine development.

Unveiling the contemporary progress of graphene-based nanomaterials with a particular focus on the removal of contaminants from water: a comprehensive review

Water scarcity and pollution pose significant challenges to global environmental sustainability and public health. As these concerns intensify, the quest for innovative and efficient water treatment technologies becomes paramount. In recent years, graphene-based nanomaterials have emerged as frontrunners in this pursuit, showcasing exceptional properties that hold immense promise for addressing water contamination issues. Graphene, a single layer of carbon atoms arranged in a hexagonal lattice, exhibits extraordinary mechanical, electrical, and chemical properties. These inherent characteristics have led to a surge of interest in leveraging graphene derivatives, such as graphene oxide (GO), reduced graphene oxide and functionalized graphene, for water treatment applications. The ability of graphene-based nanomaterials to adsorb, catalyze, and photocatalyze contaminants makes them highly versatile in addressing diverse pollutants present in water sources. This review will delve into the synthesis methods employed for graphene-based nanomaterials and explore the structural modifications and functionalization strategies implemented to increase their pollutant removal performance in water treatment. By offering a critical analysis of existing literature and highlighting recent innovations, it will guide future research toward the rational design and optimization of graphene-based nanomaterials for water decontamination. The exploration of interdisciplinary approaches and cutting-edge technologies underscores the evolving landscape of graphene-based water treatment, fostering a path toward sustainable and scalable solutions. Overall, the authors believe that this review will serve as a valuable resource for researchers, engineers, and policymakers working toward sustainable and effective solutions for water purification.

Role of graphene in scavenging methyl cations: a DFT study

CONTEXT

It is known that methylating agents methylate DNA by transferring a methyl cation (CH3+) to the nucleophilic sites in DNA bases and DNA methylation is implicated in cancer and other pathological conditions. Therefore, it is important to scavenge CH3+ ion in order to protect DNA from methylation. Graphene is considered to be a versatile material for use in a wide variety of fields including sensors, antioxidants, drug delivery and DNA sequencing. In this work, we have theoretically investigated the interaction of CH3+ ions with graphene surface with an aim to understand if pristine graphene can be used as a substrate to adsorb CH3+ cations generated from harmful methylating agents. The computed adsorption energies show that adsorption of one, two and three CH3+ ions on graphene is favourable as the adducts thus formed are found to be substantially stable in both gas phase and aqueous media. The Bader charge transfer analysis and density of states (DOS) calculation also indicate a strong interaction between graphene and CH3+ ions. Thus, our results show that pristine graphene can be used as a substrate to scavenge CH3+ ions.

METHODS

The spin polarised density functional theory (DFT) calculations employing PBE functional, ultrasoft pseudopotentials and plane wave basis set having kinetic energy cut-offs of 40 Ry and 400 Ry, respectively, for wave functions and charge densities were carried out to study the adsorption of CH3+ ion(s) on the pristine graphene surface. The Grimme's DFT-D2 method was used for the estimation of van der Waals interactions. The 'dipole correction' along z-direction was also applied for adsorption study. The Marzari-Vanderbilt smearing and Monkhorst-Pack k-point grid were employed for the Brillouin zone sampling. A 6 × 6 graphene supercell with a vertical cell dimension of 18 Å was considered for the adsorption study. The charge transfer between the CH3+ ion(s) and graphene was estimated using Bader charge analysis. The implicit solvation model (SCCS) was used to estimate the solvent effect of aqueous media. All the calculations were performed using QUANTUM ESPRESSO package.

Cytotoxicity of Carbon Nanotubes, Graphene, Fullerenes, and Dots

The cytotoxicity of carbon nanomaterials is a very important issue for microorganisms, animals, and humans. Here, we discuss the issues of cytotoxicity of carbon nanomaterials, carbon nanotubes, graphene, fullerene, and dots. Cytotoxicity issues, such as cell viability and drug release, are considered. The main part of the review is dedicated to important cell viability issues. They are presented for A549 human melanoma, E. coli, osteosarcoma, U2-OS, SAOS-2, MG63, U87, and U118 cell lines. Then, important drug release issues are discussed. Bioimaging results are shown here to illustrate the use of carbon derivatives as markers in any type of imaging used in vivo/in vitro. Finally, perspectives of the field are presented. The important issue is single-cell viability. It can allow a correlation of the functionality of organelles of single cells with the development of cancer. Such organelles are mitochondria, nuclei, vacuoles, and reticulum. It allows for finding biochemical evidence of cancer prevention in single cells. The development of investigation methods for single-cell level detection of viability stimulates the cytotoxicity investigative field. The development of single-cell microscopy is needed to improve the resolution and accuracy of investigations. The importance of cytotoxicity is drug release. It is important to control the amount of drug that is released. This is performed with pH, temperature, and electric stimulation. Further development of drug loading and bioimaging is important to decrease the cytotoxicity of carbon nanomaterials. We hope that this review is useful for researchers from all disciplines across the world.

Graphene-based nanomaterials for stimuli-sensitive controlled delivery of therapeutic molecules

Stimuli-responsive drug delivery has attracted tremendous attention in the past decades. It provides a spatial- and temporal-controlled release in response to different triggers, thus enabling highly efficient drug delivery and minimizing drug side effects. Graphene-based nanomaterials have been broadly explored, and they show great potential in smart drug delivery due to their stimuli-responsive behavior and high loading capacity for an extended range of drug molecules. These characteristics are a result of high surface area, mechanical stability and chemical stability, and excellent optical, electrical, and thermal properties. Their great and infinite functionalization potential also allows them to be integrated into several types of polymers, macromolecules, or other nanoparticles, leading to the fabrication of novel nanocarriers with enhanced biocompatibility and trigger-sensitive properties. Thus, numerous studies have been dedicated to graphene modification and functionalization. In the current review, we introduce graphene derivatives and different graphene-based nanomaterials utilized in drug delivery and discuss the most important advances in their functionalization and modification. Also, their potential and progress in an intelligent drug release in response to different types of stimuli either endogenous (pH, redox conditions, and reactive oxygen species (ROS)) or exogenous (temperature, near-infrared (NIR) radiation, and electric field) will be debated.

Recent Advances in Metal-Organic Framework (MOF) Asymmetric Membranes/Composites for Biomedical Applications

Metal-organic frameworks (MOFs) are a new class of porous crystalline materials composed of metal and organic material. MOFs have fascinating properties, such as fine tunability, large specific surface area, and high porosity. MOFs are widely used for environmental protection, biosensors, regenerative medicine, medical engineering, cell therapy, catalysts, and drug delivery. Recent studies have reported various significant properties of MOFs for biomedical applications, such as drug detection and delivery. In contrast, MOFs have limitations such as low stability and low specificity in binding to the target. MOF-based membranes improve the stability and specificity of conventional MOFs by increasing the surface area and developing the possibility of MOF-ligand binding, while conjugated membranes dramatically increase the area of active functional groups. This special property makes them attractive for drug and biosensor fabrication, as both the spreading and solubility components of the porosity can be changed. Asymmetric membranes are a structure with high potential in the biomedical field, due to the different characteristics on its two surfaces, the possibility of adjusting various properties such as the size of porosity, transfer rate and selectivity, and surface properties such as hydrophilicity and hydrophobicity. MOF assisted asymmetric membranes can provide a platform with different properties and characteristics in the biomedical field. The latest version of MOF materials/membranes has several potential applications, especially in medical engineering, cell therapy, drug delivery, and regenerative medicine, which will be discussed in this review, along with their advantages, disadvantages, and challenges.

Robust FDTD Modeling of Graphene-Based Conductive Materials with Transient Features for Advanced Antenna Applications

The accurate modeling of frequency-dispersive materials is a challenging task, especially when a scheme with a transient nature is utilized, as it is the case of the finite-difference time-domain method. In this work, a novel implementation for the modeling of graphene-oriented dispersive materials via the piecewise linear recursive convolution scheme, is introduced, while the time-varying conductivity feature is, additionally, launched. The proposed algorithm is employed to design a reduced graphene-oxide antenna operating at 6 GHz. The transient response to graphene's conductivity variations is thoroughly studied and a strategy to enhance the antenna performance by exploiting the time-varying graphene oxide is proposed. Finally, the use of the featured antenna for modern sensing applications is demonstrated through the real-time monitoring of voltage variation.

An Update on Graphene Oxide: Applications and Toxicity

Graphene oxide (GO) has attracted much attention in the past few years because of its interesting and promising electrical, thermal, mechanical, and structural properties. These properties can be altered, as GO can be readily functionalized. Brodie synthesized the GO in 1859 by reacting graphite with KClO3 in the presence of fuming HNO3; the reaction took 3-4 days to complete at 333 K. Since then, various schemes have been developed to reduce the reaction time, increase the yield, and minimize the release of toxic byproducts (NO2 and N2O4). The modified Hummers method has been widely accepted to produce GO in bulk. Due to its versatile characteristics, GO has a wide range of applications in different fields like tissue engineering, photocatalysis, catalysis, and biomedical applications. Its porous structure is considered appropriate for tissue and organ regeneration. Various branches of tissue engineering are being extensively explored, such as bone, neural, dentistry, cartilage, and skin tissue engineering. The band gap of GO can be easily tuned, and therefore it has a wide range of photocatalytic applications as well: the degradation of organic contaminants, hydrogen generation, and CO2 reduction, etc. GO could be a potential nanocarrier in drug delivery systems, gene delivery, biological sensing, and antibacterial nanocomposites due to its large surface area and high density, as it is highly functionalized with oxygen-containing functional groups. GO or its composites are found to be toxic to various biological species and as also discussed in this review. It has been observed that superoxide dismutase (SOD) and reactive oxygen species (ROS) levels gradually increase over a period after GO is introduced in the biological systems. Hence, GO at specific concentrations is toxic for various species like earthworms, Chironomus riparius, Zebrafish, etc.

Enhanced aqueous dissolution of hydrophobic apixaban via direct incorporation of hydrophilic nanographene oxide

In this study, we have directly incorporated nanographene oxide (nGO) into a hydrophobic drug for enhanced dissolution performance through an antisolvent technique. Apixaban (APX) drug composites were synthesized with nGO incorporation ranging from 0.8% to 2.0% concentration. It was observed that the nGO was successfully embedded without any changes to the original drug crystal structure or physical properties. Dissolution of the drug composites was evaluated using US Pharmacopeia Paddle Method (USP 42). The time needed to reach a 50% release (T₅₀) reduced from 106 min to 24 min with the integration of 1.96% nGO in APX and the T₈₀ also dropped accordingly. Alternatively, dissolution rate showed promising performance with increase in nGO concentration. Initial dissolution rate increased dramatically from 74 µg/min to 540 µg/min. Further, work done in intestinal media revealed T₅₀ went from not dissolving to 79.0 min. Decreased lipophilicity or logP value and increased aqueous solubility are both accredited to hydrophilic nGO water dispersion, producing a hydrophilic channel into the drug crystal surfaces through intermolecular interaction. Additionally, physical, and chemical characterizations confirm that hydrophobic apixaban was successfully transformed into a hydrophilic composite, showing potential for this technology to improve dissolution rate of a model hydrophobic compound.

Drug Release Kinetics of DOX-Loaded Graphene-Based Nanocarriers for Ovarian and Breast Cancer Therapeutics

Cancer remains one of the leading causes of death worldwide despite extensive efforts at developing curative treatments. Chemotherapy, one of the most common forms of treatment, lacks specificity and can induce collateral damages to healthy surrounding tissues/cells and elicit off-target toxic side effects. The carbon-based nanomaterial graphene, can load aromatic drugs with high efficiency, has good biocompatibility, and can be easily functionalised with targeting ligands, antibodies, and biomolecules to increase the accuracy of targeting specific areas; graphene has therefore been explored as a nanocarrier for classical chemotherapy drugs. In this work, seventeen publications that report the release of doxorubicin (DOX) from 2D graphene-based nanohybrids (graphene oxide and reduced graphene oxide) for the treatment of breast and ovarian cancers have been identified based on a range of inclusion and exclusion criteria. To aid in the clinical translation of proof-of-concept studies, this work identifies the pre-clinical experimental protocols and analyses the release kinetics of these publications. Fifteen of the papers utilised a change in pH as the stimulus for drug release, and two utilised either near infrared (NIR) or ultrasound as the stimulus. The extracted drug release data from these publications were fit to four known kinetic models. It was found that the majority of these data best fit the Weibull kinetic model. The agreement between the kinetic data in previously published literature provides a predictable estimation of DOX release from graphene-based nanocarriers. This study demonstrates the potential conjugation of graphene and DOX in drug delivery applications, and this knowledge can help improve to the design and formulation of future graphene-based nanocarriers. In addition, the use of further experimental testing and the standardisation of experimental protocols will be beneficial for future work. The incorporation of computational modelling prior to pre-clinical testing will also aid in the development of controlled and sustained DOX release systems that offer efficient and efficacious results.

Hepatotoxicity of graphene oxide in Wistar rats

Graphene oxide (GO) has a multitude of applications in areas of nanomedicine, electronics, textile, water purification, and catalysis among others. GO is relatively easier to manufacture and customize as compared with other carbon-based nanomaterials. In the present work, GO was administered intraperitoneally to adult Wistar rats in four incremental doses, i.e., 0.0 mg/kg (control), 0.4 mg/kg (low dose), 2.0 mg/kg (mid-dose), and 10.0 mg/kg (high dose). After 15 repeated doses over a period of 30 days, biochemical assays for alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), catalase (CAT), and malondialdehyde (MDA) were carried out. Histopathological and morphometric analyses of liver and kidney were also performed. Results demonstrated dose-dependent toxicity of GO. General behavior and liver indices remained unaffected in the study. Serum levels of ALT, ALP, and AST were altered significantly in high-dose treated animals. Changes were found insignificant in the low- and mid-dose groups. Catalase activity in liver tissue homogenates was decreased in the high-dose group. MDA levels were found elevated in treated rats. Unlike control and low dose, mid- and high-dose treated rats exhibited varying degrees of histopathological changes like inflammation around the central vein and portal veins, vacuolations, hepatocytic injury, and near normal to abnormal hepatic sinusoids. These findings show that GO has considerable toxic potential to mammalian liver and thorough toxicity studies are needed before these nanosheets are used in biomedicine.

In situ reduced graphene-based aerogels embedded with gold nanoparticles for real-time humidity sensing and toxic dyes elimination

Hybrid aerogels are promising candidates for energy storage, biosensing, and medical applications, but the conventional fabrication methods, being time-consuming and complex, limit their widespread utilization. The critical issues affecting their functionality include the un-controllable particle dispersity, loading of active materials, and the porosity. We report a simple and efficient method to synthesize in situ reduced Au nanoparticles@graphene (Au@graphene) hybrid aerogel using near-infrared radiation (NIR), resulting the uniform loading of well-dispersed Au nanoparticles (Au-NPs) as well as in situ reduction of graphene oxide (GO) with enhanced conductivity. The concentration of iso-propylacrylamide and GO can be adjusted to control the aerogel pore size during the freeze-drying process. Reduction of HAuCl₄ and GO to high extent under NIR light was confirmed with advanced characterization techniques. Density functional theory based calculations with generalized gradient-corrected functional (GGA/PW91) in the hybrid aerogel system, and dnd basis sets are used for the confirmation of possible interactions between the GO, Au-NPs, and the polymer. The as-designed highly porous and conductive aerogel shows an excellent humidity response (30-97%) and successfully removes the methylene blue pollutant from the aqueous solution to a high extent (90%). Therefore, Au@graphene hybrid aerogel is potentially an exciting candidate for a wide range of applications in the humidity sensing and biomedical disease detection.

Electrospun Composites Made of Reduced Graphene Oxide and Polyacrylonitrile-Based Activated Carbon Nanofibers (rGO/ACNF) for Enhanced CO2 Adsorption

In this work, we report the preparation of polyacrylonitrile (PAN)-based activated carbon nanofibers composited with different concentrations of reduced graphene oxide (rGO/ACNF) (1%, 5%, and 10% relative to PAN weight) by a simple electrospinning method. The electrospun nanofibers (NFs) were carbonized and physically activated to obtain activated carbon nanofibers (ACNFs). Texture, surface and elemental properties of the pristine ACNFs and composites were characterized using various techniques. In comparison to pristine ACNF, the incorporation of rGO led to changes in surface and textural characteristics such as specific surface area (S_BET), total pore volume (V_total), and micropore volume (V_micro) of 373 m²/g, 0.22 cm³/g, and 0.15 cm³/g, respectively, which is much higher than the pristine ACNFs (e.g., S_BET = 139 m²/g). The structural and morphological properties of the pristine ACNFs and their composites were studied by Raman spectroscopy and X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) respectively. Carbon dioxide (CO₂) adsorption on the pristine ACNFs and rGO/ACNF composites was evaluated at different pressures (5, 10, and 15 bars) based on static volumetric adsorption. At 15 bar, the composite with 10% of rGO (rGO/ACNF0.1) that had the highest S_BET, V_total, and V_micro, as confirmed with BET model, exhibited the highest CO₂ uptake of 58 mmol/g. These results point out that both surface and texture have a strong influence on the performance of CO₂ adsorption. Interestingly, at p < 10 bar, the adsorption process of CO₂ was found to be quite well fitted by pseudo-second order model (i.e., the chemisorption), whilst at 15 bar, physisorption prevailed, which was explained by the pseudo-first order model.

Modulation of virulence in Enterococcus faecalis cells surviving antimicrobial photodynamic inactivation with reduced graphene oxide-curcumin: An ex vivo biofilm model

BACKGROUND

Enterococcus faecalis, as a major microorganism in persistent/secondary infections of endodontically treated teeth, is less likely to be eliminated during endodontic therapy. In this study, the effect of root canal disinfection and anti-virulence activities of photodynamic inactivation (PDI) of E. faecalis utilizing reduced graphene oxide-curcumin (rGO-Cur) as a photosensitizing agent following irradiation with light-emitting diode (LED), as well as intracellular ROS production were evaluated on ex vivo biofilms of E. faecalis in comparison with sodium hypochlorite (NaOCl) as the traditional endodontic irrigation solution.

MATERIALS AND METHODS

After formulation and confirmation of synthesized rGO-Cur using scanning electron microscopy (SEM), Fourier transformation infrared (FT-IR), UV-Vis spectra, dynamic light scattering (DLS), and Zeta potential, the minimum biofilm inhibitory concentrations (MBICs) and in vitro anti-biofilm activity of rGO-Cur, light-emitting diode (LED) at the wavelength of 435 ± 20 nm, and rGO-Cur-PDI were determined against 4-week-old pre-formed biofilms of E. faecalis. After preparation of ex vivo biofilm model in root canals, the ex-vivo anti-biofilm potential of rGO-Cur, LED, and rGO-Cur-PDI against E. faecalis were analyzed using the XTT assay and scanning electron microscopy (SEM) in comparison with NaOCl. The effects of sub-MBIC of rGO-Cur and NaOCl, sub-lethal dose of LED, and sub-significant inhibitory (SSI) potential of rGO-Cur-PDI for E. faecalis biofilms on virulence genes (efa, esp, gel, and fsr) expression of E. faecalis were analyzed using real-time polymerase chain reaction (qRT-PCR) assay. Intracellular reactive oxygen species (ROS) level was measured in rGO-Cur-PDI-treated bacterial cells compared to control cells with 2',7'-dichlorfluorescein-diacetate (DCFH-DA) fluorescent probe.

RESULTS

The FTIR, DLS, Zeta potential, SEM, and UV-Vis spectra analysis indicated the successful synthesis of rGO-Cur. The MBIC of rGO-Cur was 250 μg/ml, which inhibited the growth ofE. faecalis. LED showed insignificant anti-biofilm activity against E. faecalis even after treating for a long irradiation time (300 s). According to checkerboard assay, the MBIC value of rGO-Cur-PDI was reduced noticeably compared to the individual MBIC values of rGO-Cur and LED for E. faecalis. The expression levels of efa, esp, gel, and fsr genes in pre-formed E. faecalis biofilms were markedly reduced after rGO-Cur, rGO-Cur-PDI, and NaOCl treatment in comparison with the control group. Conversely, LED revealed no significant change in the expression of the virulence genes. The intracellular ROS assay showed a significant increase (8.3-fold) in rGO-Cur-PDI when compared to the control.

CONCLUSION

Our data support that rGO-Cur-PDI showed dual inhibitory effects on biofilm formation ability and virulence activity of E. faecalis with potential clinical applications for infection control in endodontics.

Fullerene C60 containing porphyrin-like metal center as drug delivery system for ibuprofen drug

Today, drug delivery systems based on nanostructures have become the most efficient to be studied. Recent studies revealed that the fullerenes can be used as drug carriers and transport drugs in a target cell. The aim of the present work is to study the interaction of C60 fullerene containing porphyrin-like transition metal-N4 clusters (TMN4C55, TM = Fe, Co, and Ni) with a non-steroidal anti-inflammatory drug (ibuprofen (Ibp)) by employing the method of the density functional theory. Results showed that the C60 fullerene with TMN4 clusters could significantly enhance the tendency of C60 for adsorption of ibuprofen drug. Also, our ultraviolet-visible results show that the electronic spectra of Ibp/TMN4C55 complexes exhibit a blue shift toward lower wavelengths (higher energies). It was found that the NiN4C55 fullerene had high chemical reactivity, which was important for binding of the drug onto the carrier surface. In order to gain insight into the binding features of Ibp/TMN4C55 complexes, the atoms in molecules analysis was also performed. Our results exhibit the electrostatic features of the Ibp/TMN4C55 bonding. Consequently, this study demonstrated that the TMN4C55 fullerenes could be used as potential carriers for delivery of Ibp drug in the nanomedicine domain. Graphical Abstract The TMN4C55 (TM=Fe, Co, and Ni) fullerenes could be used as potential carriers for delivery of ibuprofen drug in the nanomedicine domain.

Sustainable Drug Delivery of Famotidine Using Chitosan-Functionalized Graphene Oxide as Nanocarrier

This work mainly focuses on the graphene oxide (GO)-assisted sustainable drug delivery of famotidine (FMT) drug. Famotidine is loaded onto GO and encapsulated by chitosan (CH). UV-visible spectroscopy, field emission scan electron microscopy, and atomic force microscopy confirm the loading of FMT on GO. An interaction of FMT with GO and CH through amine functionalities is confirmed by Fourier-transform infrared spectroscopy. Differential scanning calorimetric and cyclic voltammetric investigations confirm the compatibility of FMT and its retaining activity within chitosan-functionalized graphene oxide (CHGO) composite. Encapsulation efficiency of FMT is determined for various CHGO-FMT combinations and found to be higher at 1:9 ratio. The in vitro drug release profile is studied using a dissolution test apparatus in 0.1 m phosphate buffer medium (pH = 4.5), which shows sustainable drug release up to 12 h, which is greater than the market product (Complete release within 2 h). Comparative study of drug encapsulated with CH and without GO elucidates that GO is responsible for the sustainable release. The "n" value obtained from slope using Korsmeyer-Peppas model suggests the super case-II transport mechanism.

Synthesis of Three-Dimensional Graphene-Based Hybrid Materials for Water Purification: A Review

Graphene-based nanostructures and nanomaterials have been widely used for the applications in materials science, biomedicine, tissue engineering, sensors, energy, catalysis, and environmental science due to their unique physical, chemical, and electronic properties. Compared to two-dimensional (2D) graphene materials, three-dimensional (3D) graphene-based hybrid materials (GBHMs) exhibited higher surface area and special porous structure, making them excellent candidates for practical applications in water purification. In this work, we present recent advances in the synthesis and water remediation applications of 3D GBHMs. More details on the synthesis strategies of GBHMs, the water treatment techniques, and the adsorption/removal of various pollutants from water systems with GBHMs are demonstrated and discussed. It is expected that this work will attract wide interests on the structural design and facile synthesis of novel 3D GBHMs, and promote the advanced applications of 3D GBHMs in energy and environmental fields.

A Study on Technology Competition of Graphene Biomedical Technology Based on Patent Analysis

Graphene, with high biocompatibility, physiological solubility and stability, has been reported as an emerging material for biomedical applications such as biosensors, drug delivery, and tissue engineering. Recently, identifying the technological competition (TC) of graphene biomedical technology has received worldwide attention from stakeholders. However, few studies have attached great importance to review the TC of this field by the analysis of patents. The main objective of this study is to develop a new and comprehensive method to investigate TC in a given technology field by conducting a patent review and then employing a patent roadmap to dig out the technology opportunity. The effectiveness of the approach is verified with the case study on graphene biomedical technology. Compared to previous research, this study makes the following important contributions. First, this study provides a new and systematic framework for the dynamic analysis of TC in a given technology field. It also extends the research perspectives of TC for industry, assignees, and technology, employs a patent roadmap to dig out technology opportunities, and enables stakeholders to understand TC from a dynamic perspective. Second, this study integrates patent analysis with a patent roadmap that has not appeared in existing methodologies of patent review. Third, it first introduces indicators (e.g., high value patent and competition position of top assignees) to the previous patent roadmap and provides a new methodology for patent roadmaps from a country level and assignee level. Finally, this study provides useful information for stakeholders interested in graphene biomedical technology, helps them to find new technology opportunities in this field, encourages them to determine the direction of future research, and has important significance for its application to diverse other emerging technologies.

Graphene-Based Smart Platforms for Combined Cancer Therapy

The extensive research of graphene and its derivatives in biomedical applications during the past few years has witnessed its significance in the field of nanomedicine. Starting from simple drug delivery systems, the application of graphene and its derivatives has been extended to a versatile platform of multiple therapeutic modalities, including photothermal therapy, photodynamic therapy, magnetic hyperthermia therapy, and sonodynamic therapy. In addition to monotherapy, graphene-based materials are widely applied in combined therapies for enhanced anticancer activity and reduced side effects. In particular, graphene-based materials are often designed and fabricated as "smart" platforms for stimuli-responsive nanocarriers, whose therapeutic effects can be activated by the tumor microenvironment, such as acidic pH and elevated glutathione (termed as "endogenous stimuli"), or light, magnetic, or ultrasonic stimuli (termed as "exogenous stimuli"). Herein, the recent advances of smart graphene platforms for combined therapy applications are presented, starting with the principle for the design of graphene-based smart platforms in combined therapy applications. Next, recent advances of combined therapies contributed by graphene-based materials, including chemotherapy-based, photothermal-therapy-based, and ultrasound-therapy-based synergistic therapy, are outlined. In addition, current challenges and future prospects regarding this promising field are discussed.

Removing Metal Ions from Water with Graphene⁻Bovine Serum Albumin Hybrid Membrane

Here we report the fabrication of graphene oxide (GO)-based membranes covalently combined with bovine serum albumin (BSA) for metal ions detection. In this system, BSA acts as a transporter protein in the membrane and endows the membrane with selective recognition of Co2+, Cu2+, AuCl₄-, and Fe2+. Combining the metal-binding ability of BSA and the large surface area of GO, the hybrid membrane can be used as a water purification strategy to selectively absorb a large amount of AuCl₄- from HAuCl₄ solution. Moreover, BSA could reduce the membrane-immobilized AuCl₄- by adding sodium borohydride (NaBH₄). Interestingly, adsorption experiments on three kinds of metal ions showed that the GO⁻BSA membrane had good selective adsorption of Co2+ compared with Cu2+ and Fe2+. The morphology and composition changes of the membrane were observed with atomic force microscopy (AFM) and Raman spectroscopy, respectively. It is expected that this facile strategy for fabricating large-scale graphene-biomolecule membranes will spark inspirations in the development of functional nanomaterials and wastewater purification.

Efficient Removal of Lead Ions from Water by a Low-Cost Alginate-Melamine Hybrid Sorbent

A low-cost alginate-melamine hybrid sorbent (named as Alg-Mel) was designed and synthesized for the removal of Pb2+ from water. The as-prepared Alg-Mel sorbent exhibited high affinity and selectivity to Pb2+. The selectivity coefficients of the Alg-Mel for Pb2+/Cd2+, Pb2+/Cu2+, Pb2+/Cr3+ and Pb2+/Co2+ were all over 7. It is found that the hybrid sorbent could uptake 95.4% of Pb2+ from Pb2+-containing solutions (0.48 mM), and the maximum adsorption capacity for Pb2+ reaches 1.39 mmol/g (287.7 mg/g), which is much higher than that of most reported lead ion-sorbents. Furthermore, the Alg-Mel can be regenerated by a simple acid-washing process and used repeatedly. The results of adsorption mechanism analysis reveal that the adsorption of Pb2+ by Alg-Mel is mainly ascribed to the chemical coordination and ion exchange effects.

Nanomaterials-Based Electrochemical Sensors for In Vitro and In Vivo Analyses of Neurotransmitters

Neurotransmitters are molecules that transfer chemical signals between neurons to convey messages for any action conducted by the nervous system. All neurotransmitters are medically important; the detection and analysis of these molecules play vital roles in the diagnosis and treatment of diseases. Among analytical strategies, electrochemical techniques have been identified as simple, inexpensive, and less time-consuming processes. Electrochemical analysis is based on the redox behaviors of neurotransmitters, as well as their metabolites. A variety of electrochemical techniques are available for the detection of biomolecules. However, the development of a sensing platform with high sensitivity and selectivity is challenging, and it has been found to be a bottleneck step in the analysis of neurotransmitters. Nanomaterials-based sensor platforms are fascinating for researchers because of their ability to perform the electrochemical analysis of neurotransmitters due to their improved detection efficacy, and they have been widely reported on for their sensitive detection of epinephrine, dopamine, serotonin, glutamate, acetylcholine, nitric oxide, and purines. The advancement of electroanalytical technologies and the innovation of functional nanomaterials have been assisting greatly in in vivo and in vitro analyses of neurotransmitters, especially for point-of-care clinical applications. In this review, firstly, we focus on the most commonly employed electrochemical analysis techniques, in conjunction with their working principles and abilities for the detection of neurotransmitters. Subsequently, we concentrate on the fabrication and development of nanomaterials-based electrochemical sensors and their advantages over other detection techniques. Finally, we address the challenges and the future outlook in the development of electrochemical sensors for the efficient detection of neurotransmitters.

Graphene nanoplatelets-sericin surface-modified Gum alloy for improved biological response

In this study a “Gum Metal” titanium-based alloy, Ti-31.7Nb-6.21Zr-1.4Fe-0.16O, was synthesized by melting and characterized in order to evaluate its potential for biomedical applications. The results showed that the newly developed alloy presents a very high strength, high plasticity and a low Young's modulus relative to titanium alloys currently used in medicine. For further bone implant applications, the newly synthesized alloy was surface modified with graphene nanoplatelets (GNP), sericin (SS) and graphene nanoplatelets/sericine (GNP–SS) composite films via Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The characterization of each specimen was monitored by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA) measurements, and Fourier Transform Infrared Spectroscopy (FTIR). The materials' surface analyses suggested the successful coating of GNP, SS and GNP–SS onto the alloy surface. Additionally, the activities of pre-osteoblasts such as cell adhesion, cytoskeleton organization, cell proliferation and differentiation potentials exhibited on these substrates were investigated. Results showed that the GNP–SS-coated substrate significantly enhanced the growth and osteogenic differentiation of MC3T3-E1 cells when compared to bare and GNP-coated alloy. Collectively, the results show that GNP–SS surface-modified Gum alloy can modulate the bioactivity of the pre-osteoblasts holding promise for improved biological response in vivo.

GNP–SS functionalized Gum alloy exhibits superior bioactivity in inducing in vitro osteogenesis.