Carboxyl-functionalized Graphene Research Articles

Highly Sensitive Electrochemiluminescence Biosensing Method for SARS-CoV-2 N Protein Incorporating the Micelle Probes of Quantum Dots and Dibenzoyl Peroxide Using the Screen-Printed Carbon Electrode Modified with a Carboxyl-Functionalized Graphene.

Obtaining stable electrochemiluminescence (ECL) emissions from a hydrophobic luminophore in aqueous solutions and designing a method without the use of an exogenous coreactant are promising for ECL biosensing. Here, a highly sensitive signal-on ECL immunoassay for the SARS-CoV-2 N protein was developed using micelles as an ECL tag. The micelles were prepared by coencapsulating the luminophore hydrophobic CdSe/ZnS quantum dots and coreactant dibenzoyl peroxide within the hydrophobic core of micelles. The ECL probe was obtained by covalently bonding a SARS-CoV-2 N protein-binding aptamer onto the micelle surface. The construction of the immunosensor was initiated by the immobilization of the anti-SARS-CoV-2 N protein antibody onto the screen-printed carbon electrode (SPCE) with a -COOH-functionalized surface. The surface functionalization of SPCEs was achieved through paste-exfoliated graphene, which was modified with a -COOH group through supramolecular-covalent scaffolds on SPCE. Upon achieving sandwich complexes on the immunosensor, an efficient ECL signal response at -1.4 V versus Ag/AgCl was obtained in phosphate buffer solution. The ECL assay was used for the sensitive determination of SARS-CoV-2 N protein with the linear range from 0.01 to 50 ng mL-1, and the detection limit was 3.0 pg mL-1. The immunosensor showed good reproducibility and stability, and the ECL immunoassay was used to determine the SARS-CoV-2 N protein in serum samples. The proposed approach to obtain micelles is versatile for the preparation of stable ECL luminophores by using hydrophobic materials, and the strategy provides an alternative for ECL bioassays based on the coreactant route.

Molecular Dynamics Simulation and Experimental Study of the Mechanical and Tribological Properties of GNS-COOH/PEEK/PTFE Composites.

Molecular dynamics (MD) simulations were first employed to achieve the optimal sintering temperature of carboxyl-functionalized graphene (GNS-COOH)-modified polyether ether ketone (PEEK)/polytetrafluoroethylene (PTFE) composites. A model of GNS-COOH/PEEK/PTFE composites was constructed to simulate the effects of different sintering temperatures on the mechanical and tribological properties, as well as their underlying atomic mechanisms. Samples of PTFE composites were prepared and characterized through experimental methods. Results revealed that the sintering temperature significantly affects the intermolecular forces, mechanical properties, and tribological characteristics of the composites. The agglomeration of the PEEK/PTFE composite matrix was effectively mitigated by introducing GNS-COOH. When the sintering temperature was controlled at 360 °C, the compressive strength of GNS-COOH/PEEK/PTFE composites was improved compared to GNS/PEEK/PTFE composites, albeit with a slight reduction in wear resistance. This study provides a theoretical reference for the preparation process and performance evaluation of new materials.

Dynamics of h-shape narrow bandwidth dissipative soliton in Yb-doped fiber laser

We demonstrate a narrow bandwidth mode-locked ytterbium-doped fiber laser based on the carboxyl-functionalized graphene oxide (GO-COOH). In the combination of GO-COOH and intracavity filtering effects, the narrow bandwidth spectrum exhibits an h-shape at 1060.76 nm central wavelength with a 3-dB bandwidth of 0.47 nm. Furthermore, the 3-dB bandwidth can be compressed to 0.049 nm by adjusting the polarization controller. The formation of h-shape dissipative soliton has been investigated by applying the dispersive Fourier transformation and numerical simulation. The h-shape narrow bandwidth dissipative soliton we demonstrated provides a new insight for investigating the evolution dynamics of solitons with special shapes.

Carboxyl-functionalized graphene oxide/cellulose nanofiber as adsorbents toward methylene blue

An efficient adsorbent for eliminating methylene blue (MB) from water solutions was created by combining carboxyl-functionalized graphene oxide (GO-COOH) with cellulose nanofiber. The GO-COOH was prepared using a malonic acid-choline chloride deep eutectic solvent, resulting in a carboxyl group ratio of 5.3 % and a C/O ratio of 2.15. This novel approach addresses the issue of partial reduction of GO-COOH observed in traditional preparation methods, thereby enhancing the adsorption capacity of the adsorbent for MB (611.44 mg g−1). In general, this method provides the opportunity for producing cellulose-based adsorbents for dye wastewater on a large scale, while being environmentally friendly.

Developing a versatile and resilient PVDF/CeO2@GO-COOH photocatalytic membrane for efficient treatment of antibiotic-contaminated wastewater

This study focuses on enhancing the performance of PVDF membranes by incorporating CeO2 photocatalyst in combination with carboxyl-functionalized graphene oxide (GO-COOH). The carboxyl groups of GO-COOH serve a dual purpose: providing anchoring sites for CeO2 and enhancing the interfacial interaction with the polymer. The PVDF/CeO2@GO-COOH membranes were fabricated using sequence of physical blending and phase inversion processes, resulting in significantly improved internal structure with an average pore size diameter of 1.20–1.35 nm. Moreover, the CeO2@GO-COOH photocatalyst exhibited superior compatibility with PVDF. The as-prepared PVDF/CeO2@GO-COOH photocatalytic membranes (PMs) demonstrated remarkable photocatalytic activity, outperforming PVDF/CeO2, achieving degradation efficiencies of 85.55 % for ciprofloxacin and 84.82 % for sulfanilamide (both at 20 mg/L) under UV irradiation for 150 min. Photo-filtration experiments confirmed the synergistic effect of molecular separation and photodegradation, resulting in the removal of 99.5 % of ciprofloxacin and 79.5 % of sulfanilamide, coupled with a relatively high pure water flux of 115.44 L.m−2.h−1. The PM also exhibited excellent stability, self-cleaning properties, and reusability, with a flux recovery rate (FRR) of 97.5 % after five cycles of use. Finally, the PVDF/CeO2@GO-COOH membrane holds great promise for the treatment of pharmaceutical industry wastewater, offering a comprehensive solution that combines efficient pollutant degradation, high permeate flux, stability, and reusability.

Label-free electrochemical aptasensor for ultrasensitive thrombin detection using graphene nanoplatelets and carbon nano onion-based nanocomposite

Thrombin (TB) is a protease enzyme functioning in the blood coagulation cascade. It plays an important function in a number of diseases, including thromboembolic disease, Alzheimer's disease, and cancer.Therefore, precise, and sensitive detection of TB in clinical samples is of utmost importance. In this work, we have first synthesized a nanocomposite comprised of carboxyl-functionalized graphene nanoplatelets (GNPs), carbon nano-onions (CNOs), and chitosan (CS), which was used to develop an electrochemical aptasensor for selective detection of TB. This nanocomposite modified GCE exhibited a remarkable electrochemical response and a greater surface area (216 %) than the bare GCE. The morphology of the nanomaterials and nanocomposite were characterized using FESEM, TEM, and Energy-Dispersive X-ray Spectroscopy (EDS). The Layer-by-layer fabrication of the aptasensor was studied using the CV and DPV in Fe[CN]6]3/4− redox probeat pH 7.4. The designed aptasensor displayed sensitive detection of TB from 26.74 pM to 26.74 fM with a LOD of 8.61fM. Finally, this aptasensor showed promising potential in the quantitative determination of TB in human serum. This proposed aptasensor displayed excellent sensitivity, high specificity, and satisfactory reproducibility and can be useful in biomedical applications as well as for clinical purposes.

CoVSense: Ultrasensitive Nucleocapsid Antigen Immunosensor for Rapid Clinical Detection of Wildtype and Variant SARS-CoV-2.

The widespread accessibility of commercial/clinically-viable electrochemical diagnostic systems for rapid quantification of viral proteins demands translational/preclinical investigations. Here, Covid-Sense (CoVSense) antigen testing platform; an all-in-one electrochemical nano-immunosensor for sample-to-result, self-validated, and accurate quantification of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N)-proteins in clinical examinations is developed. The platform's sensing strips benefit from a highly-sensitive, nanostructured surface, created through the incorporation of carboxyl-functionalized graphene nanosheets, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) conductive polymers, enhancing the overall conductivity of the system. The nanoengineered surface chemistry allows for compatible direct assembly of bioreceptor molecules. CoVSense offers an inexpensive (<$2 kit) and fast/digital response (<10min), measured using a customized hand-held reader (<$25), enabling data-driven outbreak management. The sensor shows 95% clinical sensitivity and 100% specificity (Ct<25), and overall sensitivity of 91% for combined symptomatic/asymptomatic cohort with wildtype SARS-CoV-2 or B.1.1.7 variant (N = 105, nasal/throat samples). The sensor correlates the N-protein levels to viral load, detecting high Ct values of ≈35, with no sample preparation steps, while outperforming the commercial rapid antigen tests. The current translational technology fills the gap in the workflow of rapid, point-of-care, and accurate diagnosis of COVID-19.

Nonlinear optical properties of carboxyl-functionalized graphene oxide for dissipative soliton resonance pulse generation

Here, we investigated the nonlinear optical (NLO) characteristics of carboxyl-functionalized graphene oxide (GO-COOH) in the near-infrared (NIR) region. The results revealed that GO-COOH samples exhibit strong saturable absorption at low pump levels and a gradual transition to reverse saturable absorption (RSA) with increasing pump power. Then the saturable absorber (SA) by depositing the GO-COOH on the side-polished fiber (SPF) was employed in Yb- and Er-doped fiber lasers. Stable ultrashort pulses operating in the dissipative soliton (DS) and conventional soliton (CS) regimes were obtained with pulse widths of 26.6 ps and 968 fs, respectively. Besides, the dissipative soliton resonance (DSR) phenomenon caused by the RSA of GO-COOH was also observed with increasing pump power. The high-stable DSR mode-locked pulses with the maximum pulse energy of 1.91 nJ and 0.74 nJ were obtained in YDFL and EDFL respectively. These results not only reveal the potentiality of GO-COOH in ultrafast photonics applications but also open a new avenue to explore high-pulse-energy laser sources based on two-dimensional materials.

Self-Assembled Nanofibrous Membranes by Electrospinning as Efficient Dye Photocatalysts for Wastewater Treatment.

Water pollution has become a leading problem due to industrial development and the resulting waste, which causes water contamination. Different materials and techniques have been developed to treat wastewater. Due to their self-assembly and photocatalytic behavior, membranes based on graphene oxide (GO) are ideal composite materials for wastewater treatment. We fabricated composite membranes from polylactic acid (PLA) and carboxylic methyl cellulose (CMC)/carboxyl-functionalized graphene oxide (GO-f-COOH) using the electrospinning technique and the thermal method. Then, a nanofibrous membrane (PLA/CMC/GO-f-COOH@Ag) was produced by loading with silver nanoparticles (Ag-NPs) to study its photocatalytic behavior. These membranes were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) in order to investigate the behavior of the fabricated membranes. The degradation kinetics studies were conducted using mathematical models, such as the pseudo first- and second-order models, by calculating their regression coefficients (R2). These membranes exhibited exceptional dye degradation kinetics. The R2 values for pseudo first order were PCGC = 0.983581, PCGC@Ag = 0.992917, and the R2 values for pseudo second order were PCGC = 0.978329, PCGC@Ag = 0.989839 for methylene blue. The degradation kinetics of Rh-B showed R2 values of PCGC = 0.973594, PCGC@Ag = 0.989832 for pseudo first order and R2 values of PCGC = 0.994392, PCGC@Ag = 0.998738 for pseudo second order. The fabricated nanofibrous membranes exhibited a strong π-π electrostatic interaction, thus providing a large surface area, and demonstrated efficient photocatalytic behavior for treating organic dyes present in wastewater. The fabricated PLA/CMC/GO-f-COOH@Ag membrane presents exceptional photocatalytic properties for the catalytic degradation of methylene blue (MB) dye. Hence, the fabricated nanofibrous membrane would be an eco-friendly system for wastewater treatment under catalytic reaction.

Introduction of a new dichlorophen electrochemical sensor relying on the modified glassy carbon electrode (GCE) with carboxyl-functionalized graphene oxide/poly (L-arginine)

Introduction of a new dichlorophen electrochemical sensor relying on the modified glassy carbon electrode (GCE) with carboxyl-functionalized graphene oxide/poly (L-arginine)

Removal Efficiency of Sulfapyridine from Contaminated Surface Water by Carboxylated Graphene Oxide Blended PVDF Composite Ultrafiltration Membrane with Activated Carbon.

In this study, sulfapyridine (SPY), an antibiotic that is less commonly treated by membrane filtration techniques but is frequently detected in the aqueous environment and at higher concentrations than other detected antibiotics, was selected for investigation. A composite ultrafiltration membrane for the removal of sulfapyridine (SPY) antibiotics from water was fabricated using polyvinylidene fluoride (PVDF), polyvinylpyrrolidone (PVP), and carboxyl-functionalized graphene oxide (CFGO) as additives. The changes in retention rate and pure water flux of sulfapyridine by the composite ultrafiltration membrane were investigated by changing the ratios of the prepared ultrafiltration membrane materials under the conditions of low-pressure operation to explore the optimal experimental conditions. The results showed that the addition of PVP and CFGO significantly increased the number of membrane pores and their pore size. The addition of CFGO in the membrane significantly improved the hydrophilicity of the membrane. The contact angle decreased from 83.7 to 31.6°. Compared to ordinary PVDF ultrafiltration membranes, the membrane's pure water flux increased nearly three times to 2612.95 L/(m2·h). The removal rate of SPY was 56.26% under the optimal conditions. When the composite ultrafiltration membrane was combined with activated carbon, the removal rate of SPY was 92.67%, which was nine times higher than that of activated carbon alone. At this time, the flux of the composite membrane was 2610.23 L/(m2·h). This study proposes a simple, efficient, and low production cost solution for the removal of sulfapyridine from water.

On-site detection of fish furunculosis by combining DNAzyme and carboxyl-functionalized graphene.

Furunculosis, which is caused by Aeromonas salmonicida, can induce septicemia, leading to the rapid death of fishes belonging to Salmonidae, Cyprinidae, and Fuscheridae, and lamprey. Targeting A. salmonicida, five DNAzyme sequences with the highest enrichment rates were selected through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX). The enrichment rates were 34.78, 23.60, 8.91, 2.89, and 2.34%, respectively. The DNAzyme with the highest activity, named D-AS-2, showed specificity and sensitivity. D-AS-2 was combined with carboxyl-functionalized graphene to construct a biosensor, which showed good fluorescence response to scabies lesion samples. The diagnostic procedure was completed in <2min and can be used for the on-site diagnosis of fish diseases. A low-cost, rapid, simple, and highly specific biosensor for the diagnosis of furunculosis was established based on DNAzyme and carboxyl-functionalized graphene.

Carboxyl-functionalized graphene reinforced aromatic polyamide nanocomposites

Carboxyl-functionalized graphene (CG)reinforced aromatic polyamide (PA) nanocomposites (CGPA) were prepared with CG nanofillers (1, 3 and 5 wt.%) by the delamination/adsorption method. PA was synthesized by 2,6-pyridine dicarboxylic acid with aromatic diamine via direct polycondensation reaction. The prepared CGPA nanocomposites were evaluated through Fourier transform infrared techniques (FTIR), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), differential scanning calorimetric (DSC) and thermogravimetric analysis (TGA). The results showed that the melting temperatures (Tm) of CGPA nanocomposites were significantly increased from 289°C to 359°C. The thermal decomposition temperature was improved by ∼13°C with the incorporation of CG nanofiller. CG nanofillers play a significant role in improving the thermal properties of CGPA nanocomposites.

Efficient Eradication of Bacterial Biofilms with Highly Specific Graphene-Based Nanocomposite Sheets.

Bacterial biofilms are usually resistant to antibiotics, thus powerful methods are required for removal. Nanomaterial involving a combination of treatment modalities recently has been recognized as an effective alternative to combat biofilm. However, its targeted and controlled release in bacterial infection is still a major challenge. Here, we present an intelligent phototherapeutic nanoplatform consisting of an aptamer (Apt), indocyanine green (ICG), and carboxyl-functionalized graphene oxide (GO-COOH), namely, ICG@GO-Apt, for targeted treatment of the biofilm formed by Salmonella Typhimurium. Since Apt-conjugated nanosheets (NSs) can specifically accumulate near abscess caused by the pathogens, they enhance greatly the local drug molecule concentration and promote their precise delivery. They can simultaneously generate heat and reactive oxygen species under near-infrared irradiation for photothermal/photodynamic therapy, thereby significantly enhancing biofilm elimination. The phototherapeutic ICG@GO-Apt also displays a good biocompatibility. More importantly, the multifunction phototherapeutic platform shows an efficient biofilm elimination with an efficiency of greater than 99.99% in an abscess formation model. Therefore, ICG@GO-Apt NSs with bacteria-targeting capability provide a reliable tool for clinical bacterial infection that circumvents antibiotic resistance.

Ultrasensitive photoelectrochemical microcystin-LR immunosensor using carboxyl-functionalized graphene oxide enhanced gold nanoclusters for signal amplification

An ultrasensitive photoelectrochemical (PEC) immunosensor based on gold nanoclusters (AuNCs) with 11-mercaptoundecanoic acid (MUA) ligands was fabricated for determination of microcystin-LR (MC-LR). The PEC immunosensor was developed by loading the monoclonal MC-LR antibody (Ab) to the MUA-AuNCs modified gold electrodes. After different measurement conditions being optimized, silver nanoparticles (AgNPs), gold nanorods (AuNRs), graphene oxide (GO) and carboxyl-functionalized graphene oxide (cGO) were introduced into MUA-AuNCs to enhance the sensing properties. The experimental result revealed that the sensitivity of PEC immunosensors was enhanced by both their photoelectrochemical properties and antibody loading properties with dependent relationship, which was different from the enhancement strategy of PEC sensors based on redox reactions. Among different hybrid nanocomposites, MUA-AuNCs/cGO not only improved the photoelectrochemical properties, but also loaded more antibodies for sensing, which resulted in best sensing performance. Thus, a universal method was proposed to enhance the sensing performance of PEC immunosensors based on impedance changes. Finally, MUA-AuNCs/cGO based PEC immunosensors exhibited a wide linear range of 0.001 nM–1000 nM with low detection limit of 0.011 pM (S/N = 3) for MC-LR determination. Meanwhile, the designed PEC immunosensors showed high selectivity, reproducibility and specificity, which provided the promising applications in aquatic environment.

Ultraflat Langmuir–Blodgett assembled graphene oxide saturable-absorber films for pulsed near-infrared laser generation

Large-scale production of ultraflat broadband saturable-absorber films is highly desired for passive mode-locked solid-state lasers. However, the current vapour deposition and spin coating routes for fabricating saturable absorbers (SAs) are suffering from the limited flexibility in substrate choice and complexity of mass production processes. Here, we demonstrate an ultraflat carboxyl-functionalized graphene oxide (GO-COOH) SA film via Langmuir–Blodgett (LB) assembly for solid state laser mode-locking. Hydrophilic carboxyl groups from GO sheets weaken the aggregation effect thus contribute to the uniform and stable dispersion of GO sheets in water. Such GO suspensions are made into an ultrathin large-area graphene-based SA film by a LB assembly process ensuring high surface uniformity. The room-temperature and highly repeated operation for GO LB films avoids the thermal damage of GO sheets and improves the membrane repeatability. Consequently, the ultrathin GO-COOH SA shows the modulation depth (2.3%) and low saturation intensity (24.7 KW cm−2) under 1064 nm laser irradiation. By inserting the GO SA into a Nd:GdVO4 laser, both passive Q-switched (QS) and passive Q-switched mode-locked (QML) operations are also attained. The slope efficiency of QS laser is up to 35.6% and the maximum single pulse energy is 1.48 μJ. In particular, the QML pulses can be achieved stably and repeatedly with an average output power of 1.33 W and a pulse energy of 13.2 nJ. Our strategy provides a new concept for improving the modulation stability of graphene-based SAs and promoting their industrial application in pulsed solid-state lasers.

Amide-functionalized graphene-assembled monoliths with high adsorption capacity of Cd2+

Three-dimensional graphene-assembled monoliths (GAs) are emerging materials used in supercapacitors, catalysis, etc. However, GAs prepared by mainstream reduction methods (reduced GAs, RGAs) have fewer functional groups and display poor adsorption capacity of heavy metals. In this paper, we developed a new method of preparing amide-functionalized GAs (AGAs) with high degree of modification by the reaction of carboxyl-functionalized graphene oxides and ethylenediamine. AGAs contained multiple functional groups and exhibited dendritic structure at micron scale. Benefiting from these properties, the maximum adsorption capacities Cd 2 + on AGAs at T = 303 K were about 56.6 mg/g, which was twice that of RGAs and higher than that of graphene ( ∼ 10 mg/g) and biochar ( ∼ 18 mg/g) at the same conditions. By calculating the Gibbs free energies ( Δ G), the adsorption of Cd 2 + on AGAs was proved a spontaneous process, while the adsorption of Cd 2 + on RGAs was not spontaneous X-ray photoelectron spectroscopy analysis demonstrated that AGAs contained more adsorption sites and Cd 2 + adsorbed on AGAs through coordination bond. Thus, AGAs exhibited good application potentials as adsorbents for the removal of Cd 2 + from contaminated water. • GAs with rich functional groups were successfully prepared. • The three-dimensional structure was constructed by forming amide groups. • Compared with RGAs, AGAs had more potential adsorption sites for heavy metals. • Compared with RGAs, AGAs had higher adsorption capacity for Cd 2+ at 30 °C. • The improved synthesis method makes the adsorption of Cd 2+ by AGAs spontaneous.

Glucose detection by gold modified carboxyl-functionalized graphene quantum dots-based surface plasmon resonance

In this work, a graphene quantum dots composite thin film-based surface plasmon resonance (SPR) sensor was developed and experimentally demonstrated for glucose detection. The proposed work incorporates the modification of SPR gold film with carboxyl-functionalized graphene quantum dots-nanocrystalline cellulose (CGQDs-NCC) to improve the detection sensitivity of glucose. The sensing performances of gold/CGQDs-NCC thin film as a function of the sensitivity and binding affinity were analysed. The experimental results show that the linear response of the gold/CGQDs-NCC thin film were 13.296° μM−1, 0.13983° μM−1 and 0.00753° μM−1 for the 0 μM to 0.03 μM, 0.03 μM to 0.5 μM and 0.5 μM–10 μM of glucose concentrations, respectively. The binding affinity has been analyzed using Langmuir and Sips model where it revealed that gold/CGQDs-NCC thin film has higher affinity constant as compared to unmodified gold film. All in all, this paper gives the idea that the introduction of gold-modified CGQDs-NCC thin film in SPR has good potential for detecting glucose solution.

Switchable single- and dual-wavelength femtosecond mode-locked Er-doped fiber laser based on carboxyl-functionalized graphene oxide saturable absorber

In this Letter, we demonstrated the switchable single- and dual-wavelength femtosecond soliton generation in single-mode Er-doped fiber lasers with the usage of carboxyl-functionalized graphene oxide (GO-COOH) saturable absorbers (SAs) for the first time, to the best of our knowledge. The fiber laser generated a stable single-wavelength conventional soliton at 1560.1 nm with a pulse duration of 548.1 fs. The dual-wavelength solitons centered at 1531.9 nm and 1555.2 nm with a spacing of approximately 23 nm can be obtained by adjusting the pump power of the cavity. Our experimental results indicated the GO-COOH has great potential to be used in ultrafast fiber lasers as broadband SAs.

Clinical Application for Screening Down's Syndrome by Using Carboxylated Graphene Oxide-Based Surface Plasmon Resonance Aptasensors.

BackgroundAdvanced medical detection technology requires high sensitivity and accuracy to increase the disease detection rate. We showed that carboxyl-functionalized graphene oxide (carboxyl-GO) biosensing materials are capable of accurate detection.MethodsWe developed a carboxylated GO-based surface plasmon resonance (SPR) aptasensor suitable for screening Down’s syndrome in clinical serum. This biosensing material could rapidly and accurately detect hCG protein with a low concentration to identify fetal Down’s syndrome. The developed carboxyl-GO-based SPR aptasensor showed excellent sensitivity and limit of detection without the use of antibodies and without any specific preference.ResultshCG protein detection limits of 1 pM in buffer samples and 1.9 pM in clinical serum samples were achieved. The results showed that the carboxyl-GO-based chip could detect hCG well below the normal physiological level of serum protein (5.0 mIU/mL). High affinity, sensitivity, and better detection limit were obtained in the range of 1.9 pM to 135 pM. The results showed a 5k-fold dilution factor, and that an SPR angle shift of more than 20 millidegrees (mo) was associated with a significant risk of fetal Down’s syndrome compared to normal pregnant women. The results clearly showed that the detection of hCG protein in serum samples from pregnant women at 12–19 weeks could be used to screen Down’s syndrome with high selectivity and sensitivity.ConclusionOur findings suggest the potential application of carboxyl-GO film in proof-of-concept studies for serum assays as a new type of SPR material. In addition, peptide and carboxyl-GO films may be conducive to the development of future point of care testing and rapid diagnostic devices for other diseases such as cancer.