Acid Modified Graphene Oxide Research Articles

High efficiency removal of methyl blue using phytic acid modified graphene oxide and adsorption mechanism

Phytic acid modified graphene oxide (PGO) has encouraging prospect in environmental application. Herein, PGO was fabricated with a simple hydrothermal method and used as adsorbent to remove methyl blue (MB). Elaborate inspection based on the hard-soft acid-base (HSAB) principle, spectroscopic characterization, as well as batch adsorption and fitting were conducted to unravel the adsorption mechanism. Results show, PGO efficiently adsorbs 89.08 mg·g−1 of MB in 22 min. HSAB principle proposes, high electron transfer (ΔN) and energy lowering (ΔE) induce covalent bond (chemical interaction), while low ΔN and ΔE induce electrostatic effect (physical interaction). Accordingly, both the first and second strongest interaction occurs between PA moiety and MB: π electrons of MB flows towards O atom in OH and O(–O–) of PA, respectively. Yet the third strongest interaction happens between GO moiety and MB: electron of O atom in OH group of GO flows towards N atom of MB. Above top three interactions are characterized by prominent ΔN and ΔE implying the formation of covalent bond. However, other interactions yield low ΔN and ΔE, suggesting the presence of electrostatic effect. HSAB principle conclusion was substantiated by FTIR and UV–Vis analyses. These findings confirm that PA modification enhances the adsorption affinity of graphene oxide. Thereby, chemical adsorption induced by physical interaction is proposed. This work may inspire the design of efficient adsorbent based on PGO framework for environmental restoration.

Biocompatibility of graphene oxide nanosheets functionalized with various amino acids towards mesenchymal stem cells

Graphene and its derivatives have gained popularity due to their numerous applications in various fields, such as biomedicine. Recent reports have revealed the severe toxic effects of these nanomaterials on cells and organs. In general, the chemical composition and surface chemistry of nanomaterials affect their biocompatibility. Therefore, the purpose of the present study was to evaluate the cytotoxicity and genotoxicity of graphene oxide (GO) synthesized by Hummer's method and functionalized by different amino acids such as lysine, methionine, aspartate, and tyrosine. The obtained nanosheets were identified by FT-IR, EDX, RAMAN, FE-SEM, and DLS techniques. In addition, trypan blue and Alamar blue methods were used to assess the cytotoxicity of mesenchymal stem cells extracted from human embryonic umbilical cord Wharton jelly (WJ-MSCs). The annexin V staining procedure was used to determine apoptotic and necrotic death. In addition, COMET and karyotyping techniques were used to assess the extent of DNA and chromosome damage. The results of the cytotoxicity assay showed that amino acid modifications significantly reduced the concentration-dependent cytotoxicity of GO to varying degrees. The GO modified with aspartic acid had the lowest cytotoxicity. There was no evidence of chromosomal damage in the karyotyping method, but in the comet assay, the samples modified with tyrosine and lysine showed the greatest DNA damage and rate of apoptosis. Overall, the aspartic acid-modified GO caused the least cellular and genetic damage to WJ-MSCs, implying its superior biomedical applications such as cell therapy and tissue engineering over GO.

Radiation synthesis of boronic acid modified graphene oxide for enhance the neutron shielding property of silicone rubber

In this study, poly(3-acrylaminophenylboronic acid) modified graphene oxide (GO-PAAPBA) has been prepared by polymerization of 3-acrylaminophenylboronic acid (AAPBA) on the surface of GO. The –O· free radical was formed by γ-ray radiation, which initiated the polymerization of AAPBA. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were employed to characterize the structure of GO-PAAPBA. The grafting density of poly(3-acrylaminophenylboronic acid) is increased with increasing of the absorbed dose. The GO-PAAPBA was added into vinyl-terminated polydimethylsiloxane (Vi-PDMS) to prepare room temperature cured silicon rubber composites (SR/GO-PAAPBA). The GO-PAAPBA exhibits better dispersion performance than pure GO, which is contribute to improve thermal conductivity and mechanical properties. Significantly, with grafting density of PAAPBA increasing, the comprehensive performances of SR/GO-PAAPBA are more remarkable. SR/GO-PAAPBA-1.88 with outstanding thermal and mechanical abilities exhibits beat neutron shielding property. The neutron transmission of SR/GO-PAAPBA-1.88 is 10% lower than that of SR. The SR nanocomposite with efficient thermal conductivity and neutron shielding ability has a promising prospect to be applied as advanced flexible shielding material.

Linear maltodextrin polymer–folic acid modified graphene oxide nanoparticles for targeted delivery and pH/photothermal sensitive release of hydrophobic anticancer drugs in tumor cells

GO@LM-SP-FA was constructed by connecting linear maltodextrin polymer and folic acid to the surface of graphene oxide nanoparticles. Doxorubicin hydrochloride was loaded into GO@LM-SP-FA to form GO@LM-SP-FA/DOX, and controlled release of anticancer drugs was realized.

Stretchable and tough tannic acid-modified graphene oxide/ polyvinyl alcohol conductive hydrogels for strain and pressure sensors

With the rise of new fields such as wearable devices, human health monitoring, and artificial intelligence, flexible sensors have received extensive attention. Conductive hydrogels combine conductive fillers with the excellent properties of hydrogels, making them ideal materials for building flexible sensors. However, conductive hydrogels suffer from poor mechanical properties and low sensitivity, and designing hydrogels with high electrical conductivity and excellent mechanical properties remains a challenge. In this work, a conductive TA-RGO/PVA hydrogel was developed by incorporating TA-RGO nanocomposites into a PVA matrix. The prepared TA-RGO/PVA hydrogel exhibited excellent electrical conductivity, good elastic strain, and excellent mechanical stress. TA-RGO/PVA hydrogels can be used for stretchable strain and pressure sensors. The strain sensor based on the TA-RGO/PVA hydrogel exhibits excellent tensile strain sensitivity (1.936 78 gage factor in the 1%–280% strain region) with excellent stability. The sensor also maintains high sensitivity when used as a pressure sensor (2.2695 kPa−1 in the 0–9 kPa pressure range). These characteristics offer the TA-RGO/PVA hydrogel great potential in the application of wearable flexible strain/pressure sensors and bioelectrodes.

New material of polyacrylic acid-modified graphene oxide composite for phenol remediation from synthetic and real wastewater

In this study, new material of polyacrylic acid-modified graphene oxide (GO-PAA) composite for phenol remediation from synthetic and real wastewater was investigated. The graphene oxide (GO) and GO-PAA were physically and chemically characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), and Brunauer–Emmet–Teller (BET). The effects of various experimental factors including pH, temperature, and initial phenol concentration were examined. Results showed that the optimum adsorption occurred at pH 2 and temperature 25 °C. The adsorption capacity of GO-PAA was double of the case of un-modified GO, indicating the importance of surface modification and the introduction of (C=O) groups in the enhancement of the adsorption process. Moreover, the Langmuir adsorption isotherm was found to be the most suitable isotherm to describe the adsorption process of phenol, and thermodynamics studies confirmed the spontaneity and the exothermic nature of the adsorption process. GO-PAA was capable of removing 75% and 18% of phenol from synthetic and real wastewater, respectively under optimum conditions of pH 2 and 25 °C. These results indicate that adsorption of phenolic compounds using GO-PAA could be an effective and simple method to remediate pollution, especially in acidic conditions. • Polyacrylic acid-modified graphene oxide (GO-PAA) was investigated for phenol adsorption. • The adsorption capacity of GO-PAA was double of the case of un-modified GO. • The % removal of GO-PAA for synthetic and real wastewater was 75 and 18, respectively. • The mechanisms of phenol adsorption on both GO and GO-PAA was mainly dominated by π – π interactions.

Fabrication of self-healing magnetic nanoreceptors for glycoprotein via integrating boronate-affinity-oriented and sequential surface imprinting

Molecularly imprinted polymers (MIPs) as artificial receptors have been widely applied in various fields. However, construction of MIPs for precise recognition of glycoprotein still remains a rather challenging task. To overcome this problem, we first fabricated boronate-affinity-oriented and sequential-surface imprinting magnetic nanoparticles (BSIMN) through integrating the boronate-affinity-oriented and sequential surface imprinting. The boronate-affinity-oriented immobilization of glycoprotein template endowed the BSIMN with homogeneous imprinted cavities. In addition, the polydopamine (PDA) imprinted layer was introduced by self-polymerization of dopamine in the first imprinting process, and then the phenylboronic acid (PBA) imprinted layer was introduced by boronate-affinity interaction in the second imprinting process. Surprisingly, the PBA imprinted layer possessed self-healing property due to the presence of pH-dependent boronate-affinity interaction between two imprinted layers. Therefore, the fabricated BSIMN exhibited excellent selectivity toward glycoprotein templates. To quantitatively detect glycoproteins in biological samples, the BSIMN was linked with hydrophilic rhodamine B-loaded/boronic acid-modified graphene oxide (HRBGO), which could selectively label glycoprotein and output amplified signal. In quantitative analysis, target glycoproteins were firstly captured by BSIMN and then specifically labeled by HRBGO; subsequently, the releasing agent was added to release numerous rhodamine B from HRBGO, and the corresponding fluorescence signal was used for further quantitative analysis. The proposed strategy showed ultrahigh sensitivity for ovalbumin, carcinoembryonic antigen and alpha fetoprotein with limit of detection of 4.5 fg mL−1, 3.6 fg mL−1 and 4.2 fg mL−1, respectively, and was successfully applied in determination of these glycoproteins in serum samples.

Electrodeposition of polypyrrole coatings doped by benzenesulfonic acid-modified graphene oxide on metallic bipolar plates

Benzenesulfonic acid (BSA)-modified graphene oxide (GO) reinforced polypyrrole (PPY) coatings were electrodeposited on metallic bipolar plates for corrosion protection. The ionization of BSA groups drove the parallel stacking of graphene oxide during the anodic deposition. Meanwhile, the doping effect of BSA groups favored the electro-polymerization of pyrrole and the π-electron delocalization of PPY. The doping level of PPY in the composite coatings increased from 15.6 % to 35.2 % when the concentration of BSA-modified GO (SGO) was increased from 1.5 mg٠mL−1 to 3 mg٠mL−1, while the surface roughness of the coatings decreased from 34.3 nm to 19.3 nm. The corrosion current density under the potentiodynamic polarization test reached 0.18 μA٠cm−2, which was an order of magnitude lower than that of the GO/PPY composite coatings. The interfacial contact resistance of the SGO/PPY coatings was 85 % lower than that of GO/PPY coatings, when the electrical conductivity was increased from 6.72 × 10−3 S٠cm−1 to 13.7 S٠cm−1. The improved performance of composite coatings was attributed to the barrier effect of parallelly stacked graphene sheets, the doping effect of BSA groups grafted on GO, and the two-dimensional template effect of SGO on PPY deposition.

Enhanced mechanical property, chemical resistance and abrasion durability of waterborne polyurethane based coating by incorporating highly dispersed polyacrylic acid modified graphene oxide

The incorporation of graphene oxide (GO) into waterborne polyurethane (WPU) coating shows great potential in enhancing the performance of WPU coating. But homogeneous dispersion of GO in polymer matrix is still a challenge for the application of GO. In this paper, the polyacrylic acid modified graphene oxide (PAA-nGO) with high dispersion stability in a wide range of pH (4–11) was prepared via two step amidation reaction. Significantly, PAA-nGO can be uniformly dispersed in WPU as bifunctional additive to prepare WPU/PAA-nGO coatings with enhanced mechanical property, chemical resistance and abrasion durability. The as-prepared WPU/PAA-nGO coating exhibited improved tensile strength (18.12 MPa) and tear strength (38.07 kN/m), which were 56.1% and 51.5% higher than those of pure WPU coating, respectively. Interestingly, WPU/PAA-nGO coating showed improved chemical resistance. Notably, abrasion durability of WPU/PAA-nGO coating was significantly enhanced, and the mass loss rate was decreased by 77.1%. Overall, this work provided a potential strategy for improving the mechanical property, chemical resistance and abrasion durability of WPU based coatings by introducing PAA-nGO with well dispersion and high stable in a wide pH range.

Acid Modified Graphene Oxide from used Battery Rods Loaded with 2-{(E)-[(3-hydroxyphenyl) imino] methyl} phenol: Electrochemical Detection of Dopamine in Presence of Ascorbic Acid and Uric Acid in Aqueous Medium

The graphite rods of used batteries have been utilized as source for Graphene Oxide (GO). The Acid Modified Graphene Oxide (AMGO) is loaded with Schiff base obtained from salicylaldehyde and 3-amino phenol. Glassy Carbon Electrode (GCE) surface when modified with the Schiff base loaded AMGO acts as electrochemical sensor for Dopamine (DA) in presence of Uric Acid (UA) and Ascorbic Acid (AA). Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV) and Differential Pulse Voltammetry (DPV) shows well separated peaks for DA from UA and AA. The DA peak intensity increases in the three techniques with DA concentration. The linear range for the detection of dopamine is observed from 9.09 × 10-4 M to 1.70 × 10-3 M in presence of 1.00 × 10-1 M Ascorbic Acid and 1.00 × 10-2 M uric acid. The detection limit is estimated to be 9.38 × 10-10 M.

Fabrication of acrylic acid modified graphene oxide (AGO)/acrylate composites and their synergistic mechanisms of anticorrosion and antifouling properties

Considering the problem of corrosion and organisms fouling encountered by marine vessels during navigation. Acrylic acid modified graphene oxide (AGO)/acrylate composites were prepared through in situ radical polymerization. The chemical composition and morphology of AGO were researched by XRD, FTIR, Raman, XPS and TEM analysis. The anticorrosion performance of AGO/acrylate composites was studied via electrochemical measurements and salt spray test. Meanwhile, the hydrolysis properties of AGO/acrylate composites in the seawater were also revealed. These results manifest that acrylic acid can be grafted on the surface of graphene oxide (GO). AGO/acrylate composites possess high corrosion resistance and mechanical strength. Moreover, AGO/acrylate composites show hydrolysis properties in slightly alkaline solution. AGO/acrylate composites based paints can exhibit self-polishing antifouling performance in the natural seawater. This research will provide a novel idea for the development of primer-topcoat coatings for marine vessels.

Improvement of the dual barrier/active corrosion inhibition function of the epoxy composite filled with zinc doped-phytic acid-modified graphene oxide nanosheets

In this research, a smart epoxy coating was designed using GO sheets functionalized (non-covalently) with phytic acid (Ph) molecules and zinc (II) cations. Ultraviolet-visible spectroscopy (UV–Vis), Raman spectroscopy, X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and inductively coupled plasma (ICP) were conducted to prove the adsorption of inhibiting species on the GO surface. Alongside the electrochemical impedance spectroscopy (EIS) and polarization methods, grazing incidence XRD (GI-XRD) and FE-SEM analyses were carried out on the plates exposed to the modified GO-containing solutions. The coated samples were subjected to the EIS, salt spray test (SST), pull-off, and cathodic delamination (CD) methods. The characterization analyses confirmed the adsorption of the Zn2+ cations and Ph molecules. The adequate inhibition efficiency of the GOZn400Ph nanosheets in the saline solution was verified by the electrochemical techniques. The GOZnPh/EP coating exhibited the highest low-frequency impedance value after 49 days (~109 Ω cm2). In addition to the superior barrier protection properties, the GOZnPh nanosheets promoted active protection ability. The inclusion of the GOZnPh increased the dry adhesion strength and reduced the adhesion loss.

Hydrophilic rhodamine B-loaded / boronic acid-modified graphene oxide nanocomposite as a substitute of enzyme-labeled second antibody for ultrasensitive detection of antibodies

Enzyme-labeled secondary antibody is often used to amplify the output signal in the process of antibody detection. However, its preparation process is complex and time-consuming. Herein, we fabricated an innovative hydrophilic rhodamine B-loaded / boronic acid-modified graphene oxide (HRBGO) nanocomposite, used as a substitute of enzyme-labeled second antibody. The synthetic HRBGO was loaded with generous rhodamine B and modified with boronic acid. Therefore, the HRBGO could selectively label the carbohydrate chains of Fc fragment of primary antibody through specific boronate affinity recognition, and then perform signal output and amplification by releasing rhodamine B. To verify the practicability of HRBGO, trastuzumab as a humanized monoclonal antibody targeting human epidermal growth factor receptor-2 (HER2) was selected as model antibody. A glycosylation site-blocked / HER2-immobilized magnetic nanoparticles (GHMN) was also prepared for selectively capturing trastuzumab from complex samples via specific immunoaffinity. Because the glycosylation sites of HER2 can also be labeled with the HRBGO by boronate affinity recognition, these sites were blocked by a masking agent to minimize the background signal. For specific and ultrasensitive detection of trastuzumab, the integration of GHMN and HRBGO was proposed and optimized in detail. Trastuzumab detection based on HRBGO consisted of three steps: specific capture, selective labeling, and output signal. The proposed strategy provided ultrahigh sensitivity with limit of detection of 0.35 fg mL-1 and was successfully applied in the detection of trastuzumab in spiked serum sample with recovery and relative standard deviation in the range of 98.7–103.8% and 3.8–6.0%, respectively. To assess universal applicability, the HRBGO was also successfully used for the determination of anti-SARS-COV2 RBD antibody in human serum sample.

Improving the performance of water-based drilling fluid using amino acid-modified graphene oxide nanocomposite as a promising additive

It is possible to take advantage of nanomaterials' properties to improve water-based drilling fluids' flux and physical properties. In this paper, glycine methyl ester hydrochloride was synthesized, and the chemical structure was verified to be used as a surface modifier of graphene oxide. At the same time, graphene oxide was prepared from graphite and chlorinated with thionyl chloride, and a nucleophilic substitution reaction was performed to increase the hydrophilicity of graphene oxide. FTIR, Raman, HRTEM, and XRD techniques have identified the prepared and obtained materials from chlorinated graphene oxide's reaction with glycine methyl ester hydrochloride. The glycine-modified graphene oxide (GO) was evaluated as drilling-fluid additives at different concentrations (2.66%, 5.32%, and 10.64%) to enhancement the thermal stability of water-based drilling fluid and reducing the filtration loss. The obtained results confirmed that the successful glycine-modified graphene oxide/bentonite to enhance both thermal stability (up to 350 °F) and filtration loss.

Amino acid modified graphene oxide for assembly of nanoparticles for wastewater treatment

The surface modifications of graphene oxide (GO) by biomolecules are widely used to increase the biocompatibility, change the hydrophobicity, solubility and surface properties of GO, and provide GO with selectivity to specific molecules. A simple, biocompatible and reproducible way to decorate GO was introduced with the help of ε-poly-L-lysine (ε-PL). The GO/PL composite showed good water dispersibility and high biocompatibility, provided multiple functional amino groups, and afforded GO with reducing property, which in turn offered an ideal platform for the deposition of metal and metal oxide nanoparticles. The as-formed GO/PL/Fe2O3 composite showed catalytic ability and adsorption capacity, along with good performance for protein interaction and immobilization. The low cost, large-scale preparation, along with the easy processability provided the GO/PL/Fe2O3 composites with variety of potential practical applications.

Nacre-like graphene oxide paper bonded with boric acid for fire early-warning sensor

Boric acid-modified graphene oxide (GO-BA) paper is prepared by a green and facile water evaporation-induced self-assembly method, and its application as an early fire-alarm sensor is investigated. The nacre structure is constructed by assembling graphene oxide (GO) and boric acid (BA) as brick and mortar, respectively. Compared with pure GO paper, improved thermal-oxidative stability is obtained for GO-BA. GO nanosheets are bonded with BA molecules by forming hydrogen bonds between hydroxyl in BA and the rich oxygen-containing functional groups on GO. Notably, the insulating GO-BA paper can be rapidly thermally reduced to conductive reduced graphene oxide under flame exposure, thus providing an ideal fire-alarm response with a quick flame-detection time of ∼0.8 s. In addition, boron oxide formed under flame attack covers the surface of GO, inhibiting further oxidation of GO paper, and effectively extending the duration time of GO-BA under combustion. These results indicate that the GO-BA paper prepared has a broad prospect in the field of fire early-alarm.

Synthesis and characterization of poly 2‐ N ‐acrylamido‐2‐methyl−1‐propane sulfonic acid functionalized graphene oxide embedded electrolyte membrane using DOE for PEMFC

A novel proton exchange membrane consisting of 2-N-acrylamido-2-methyl−1-propane sulfonic acid modified graphene oxide nanocomposite (PAMPS-mGO), carboxylated poly(vinyl chloride) (CPVC), and poly 2-N-acrylamido-2-methyl−1-propane sulfonic acid (PAMPS) has been successfully prepared by simple and scalable polymer blending methodology. Different compositions of PEM in terms of its constituting precursors such as PAMPS-mGO, CPVC, and PAMPS were optimized by Placket Burman Design and their ion exchange capacity (IEC), oxidative stability, water uptake percentage, mechanical stability, and proton conductivity were evaluated. The amounts of significant precursors were further optimized by Central Composite Design. The membrane with excellent performance in PEMFC was obtained when appropriate proportions of CPVC (10%), PAMPS (20%), and PAMPS-mGO (20%) were blended. Among all membrane with mentioned composition exhibited IEC 1.3 mmol/g, oxidative stability 97.2%, WU 40.8%, proton conductivity 151 S/cm, water content 17.43, current density 1537 mA/cm2 at 120°C, power density 566.5 mW/cm2 at 120°C, Young modulus 797 MPa, tensile strength 16.8 MPa, and elongation at break % of 2.7 MPa. These results are in good comparison with PEM based on Nafion. Thus, the CPVC, PAMPS, and PAMPS-mGO-based composite PEM is a good candidate for PEMFC at elevated temperature under anhydrous conditions.

Water-based polyurethane composite anticorrosive barrier coating via enhanced dispersion of functionalized graphene oxide in the presence of acidified multi-walled carbon nanotubes

Organic films and coatings, specifically those incorporating graphene oxide, offer many advantages as corrosion barriers due to the excellent shielding and tailorable characteristics of graphene oxide. A simple method was used to prepare a composite coating with polyurethane (PU) as a polymer matrix; gallic acid modified graphene oxide (FGO) flakes and acidified multi-walled carbon nanotubes (FMWCNTs) acted as nanoscale reinforcement. The presence of FMWCNTs improved the dispersion of FGO in PU, and the composite coating exhibited nearly no defects. The one-dimensional FMWCNTs and two-dimensional graphene oxide sheets attract each other to form a relatively stable layered structure, such that the graphene oxide sheets form a large shielding layer. The anticorrosion properties of the pristine PU and composite coatings were investigated by electrochemical impedance spectroscopy tests for 96 h. The composite coating reinforced by two carbon nanomaterials simultaneously underwent no corrosion after immersion for 96 h, and the corrosion resistance was better than that of the other coatings. The enhanced anticorrosion properties of the FMWCNT-FGO/PU composite coating are attributed to the fully exploited reinforcement effect from the network of FGO and FMWCNTs that is enabled via enhanced dispersion.

Chemical functionalization graphene oxide for the adsorption behavior of Bismarck Brown dye from aqueous solutions

The adsorption behaviour of cationic dye Bismarck brown BB onto graphene oxide GO, graphene oxide derivatives 3,3ˊ-Diaminobenzidine GODAB, and Ethylene diamine tetraacetic acid-modified graphene oxide GODABE as adsorbents from aqueous solutions were investigated and characterized by various techniques, like Fourier transform infrared spectroscopy, Field Emission Scanning Electron Microscopy, and X-ray diffraction spectroscopy. Adsorption of BB dye on modified graphene oxide was explored in a series of batch experiments under various conditions. The data were analyzed using Langmuir and Freundlich, models. The Langmuir model was found to be more suitable for the experimental data than other adsorption models. The maximum adsorption capacities were 714.28, 1428.5, and 1111.1 mg/g for GO, GODAB, and GODABE at optimum pH 3 for GO and GODAB, 5 for GODABE and the optimum agitation time were chosen as 45min for GO and 30min for both adsorbents GODAB and GODABE. Kinetic studies revealed that the pseudo-second-order model showed the best fitting to the experimental data. The thermodynamic parameters imply that the adsorption process was spontaneous and endothermic.

Glycyrrhetinic acid-modified graphene oxide mediated siRNA delivery for enhanced liver-cancer targeting therapy

Graphene oxide (GO) has attracted huge attention in biomedical field in recent years. However, limited attempts have been invested in utilizing GO on active targeted delivery for gene therapy in liver cancer treatments. Glycyrrhetinic acid (GA) has been reported to be widely used as a targeting ligand to functionalize nanomaterials to treat hepatocellular carcinoma. In this article, GA is employed as a liver targeting ligand to construct GA, polyethylene glycol (PEG), polyamidoamine dendrimer (Dendrimer) and nano-graphene oxide (NGO) conjugate (GA-PEG-NGO-Dendrimer, GPND) for siRNA delivery for the first time. As we expected, GPND exhibited excellent stability, low toxicity, negligible hemolytic activity and remarkably high transfection efficiency in vitro. We also found effective VEGFa gene silencing in both mRNA and protein level in HepG2 cells. Notably, siRNA efficiently gathered in liver tumor tissues by the delivery of GPND, and eventually the growth of tumor tissues were inhibited with enhanced targeting capability and no obvious pathological changes. Moreover, histopathological results preliminarily support the high in vivo safety of GPND/anti-VEGFa siRNA nanocomplex. Collectively, GPND/siRNA nanocomplex, with high safety, targeting and transfection as well as prolonged half-life, is a promising nanomedicine and may provide a new direction for highly-specific targeted gene therapy.